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Table of Contents - GHSport Reference Center

1. sse enne enne nnns 10 Setting the Project Name sss enne nnn einen ensis in nrte entente sns 10 The Project Folder System sss entere nnne trennen enn 11 Thie Phas 6s of a Project ui n ppt EHE ee MR dat 11 Geometry Organization Understanding the Model sse 12 Interpreting Shapes i t spettatore sit Entente e 13 The Purpose of the Hierarehy sisiran nE EEE 13 The Vessel Coordinate System ssssssssssssssees ener 14 Waterplane Coordinates esses esent nennen nnne sn nennt snnt nnns 15 Model Building Creating the Geomeetry sse 16 Starting Section Editors tsetse en a peor Maden La EE ecce ee dre c Yea 17 A Section Editor Ex rcise 2 x canta eae cde d de eo redeo 17 About Names of Parts Components and Shapes ssssssssseeennes 18 About Units in Section Editor 5 1 rodar tee aee epe eoe a rg t e 19 Entering Offsets with Section Editor eene 19 Saving Your Work Writing the Geometry File 20 The Arc Command 12 i Ri b ERU ERE ROT dune Pie ccr e epa er Eod cvv De deities 20 How Many Stations Zisis naina redibat deed eese do at Per ani dee uud 20 Making the Sail 2 3 needed er RR heel en hel aslo 20 Other SE Commands gap ae ERE Ee Pp HERD Pa EUR IE RUE dd E ue cad 21 Model Converter Importing and Exporting Geometry 24 A Model Converter
2. closes the file User generated reports and plots are also controlled through Message commands This is covered in one of the Advanced Training sessions 74 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Tank Characteristics The TC command produces tank tables and plots suitable for design work or inclusion ina T amp S book There are several options for what is to be included in the tables The default option gives tables like this TANK CHARACTERISTICS No Trim No Heel Tank HOLD1 C Contents SALT WATER at 1 025 Specific Gravity FORWARD HOLD Weight Center of Gravity FSM Ref Ht Load LONG TONS CG TCG VCG GML GMT FL LT 4 7 100 8 57 9 57 0 00 4 29 65 0 16 8 144 1 5 60 200 17 13 9 57f 0 00 4 73 32 5 8 4 144 1 6 48 300 25 70 9 57f 0 00 5 16 21 7 5 6 144 1 1 35 400 34 26 9 57f 0 00 5 60 16 2 4 2 144 1 8 23 500 42 8 9 57f 0 00 6 04 13 0 3 4 144 1 9 11 600 51 40 9 57 0 00 6 48 10 8 2 8 144 1 9 98 700 9 96 g 57 0 00 6 92 9 3 2 4 144 1 10 86 800 68 53 9 57f 0 00 7 35 B l 2 1 144 1 11 73 900 71 09 9 57f 0 00 7 79 7 2 1 9 144 1 1 000 85 66 9 65f 0 00 8 23 ego hot ci cloma i aio vo 06 06 e RR im ai s i Distances In EBET eene n nm ttr ree ai ro ias HOLD1 C Reference Point Long 0 00 Trans 0 00 Vert 0 00 Output includes Reference Point height load fraction contents weight CG and free surface information Other display options are possible
3. Output without page numbers and footer with logo With page numbers and boxed in color 03 16 09 12 24 08 Glenn Bauer Page 3 03 16 09 12 15 37 Glenn Bauer Pago 3 of 3 Gus 11 50 95 FISHING VESSEL REPORTS GHS 11 50 55 FISHING VESSEL REPORTS Bb Graphs at one pixel thickness Graph at THICK 4 and page count in effect 73 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Special Message Commands Certain special messages are recognized by the program and cause it to display information about your computer operating system and program settings ME PATH paths to certain folders used by GHS ME EXPIRE expiration time of limited or roaming licenses Other special Message commands provide for changing certain program settings ME DATEFORMAT Year Month Day sets date formatting ME ERRB T EP ON OFF turns beep on errors on or off ME REPFONT enhances NOTE font in fancy reports ME REPFONT OFF turns off enhanced NOTE font See Help MESSAGE for all of the special messages You can switch Message output that would normally go to the screen to go to a text file instead ME REPORT filespec opens the file to receive the message output Of course you would not use this if filespec is already open The APPEND parameter is available for adding to an existing file ME REPORT OFF
4. append to an existing file preview an opened file close the report file with or without printing it Parameters that you can use when opening a report allow you to control whether graphs are to be included page numbering lines per page useful for paper other than 11 long whether to use footers Three levels of visual enhancements are also available BOX boxes are drawn around tables BOX BW enhanced fancy boxes and fonts BOX COLOR adds background colors in tables Some of the features you might want to include in your reports must be specified in the printer setup which can be done either through the Report pull down menu or through the PRINT command You can select a font footer logo thickness of graphs shading left margin and more You can email report files by means of PRINT EMAIL The recipient will need to have GHS or the free GHS Public Print Utility available from the Downloads link at www ghsport com support 72 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com 23 16 09 12 04 39 less Mauer 3 16 08 12 15 37 M risar veest MEIONT and DISPLACEMENT FTATUS Basellse draft 6 178 Origin Tem Fed 3 41 deg Meeks pere Wak ght LE Lee i n 15 04 3e cer 20 308 6 4 iu Lr 3920 ae HET beer inn P TEEEERTE Egd2itieesensl TILUEEPPTTIT SEUESSTEIESS yi E I deesssirtsskrrrd Total Weighe 4 z
5. HULL HULL C DECKEDG FIXUP FV1 GF E 23 2 Another Model Converter Exercise Convert BARGE DXF into a GF file We will use the resulting Geometry File later for the for the Part Maker Exercise 41 NOFILL In this case BARGE DXF happens to be a 3D drawing with axis assignments such that we need the parameter 3D XYZ Here are the commands to put on your run file MKBARGE RF PROJECT MKBARGE IMPORT BARGE DXF BARGE GF NEWGF 3D XYZ DISPLAY 26 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com The second part of this exercise is to add parameters to the IMPORT command line to orient station O at the head log with the hull positioned aft to the left as viewed in profile plan The SCALE parameter on the IMPORT command will be useful for this You can use a negative scale factor to reverse the longitudinal coordinates Getting Into Part Maker To enter the Part Maker environment the command is ENTER PM which you can issue either from the GHS command prompt or from a Run File but not from the Executive dialog The basic layout of any session begins with ENTER PM and ends with QUIT PM All of the commands between these two will be processed by Part Maker You can include your Part Maker command sequence in any Run File The Part Maker command that creates geometry is the CREATE command This is a multi line command i e it always takes more
6. Text Editor Setup In the File menu there is a Setup Paths selection and under it the Editor Program selection allows you to specify any text editor for editing your run files Notepad is the default editor and it is quite adequate We recommend that you do not use a full featured editor since GHS only recognizes basic ASCII text The User Library Folder As you become more familiar with the power of the GHS command language you may want to have some of your Run Files easily available to you regardless of which working folder you are using Such files would be general purpose Run Files that you would reference in other Run Files In this case they would be called Library Files and would use the file name extension LF however the command structure and everything else about the file is the same as any other Run File A User Library folder can be established in which GHS will automatically look for your Library Files when needed Under the File menu Setup Paths you will find the User Library function which allows you to establish the location of your User Library folder The Executive Dialog Box Normally exceptions discussed below there will appear at program start up a GHS Executive dialog box positioned at the bottom of the GHS main screen This is also known as the Executive Wizard This is a handy helper for managing files and it has a 8 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com b
7. it in the Light Ship category within the Wizard menu About Wizards Several wizards are provided with GHS They are software extensions that make use of GHS to perform specific tasks If you have used or attempted to use wizards in other software environments you will find that GHS wizards are a little different Rather than leading you through a linear sequence of steps the GHS wizards present an interface that helps you establish the parameters of your problem then goes ahead and generates the solution complete with a report in many cases Also GHS wizards usually save your inputs so that you never have to redo things that you are not changing Some of the more elaborate wizards write run files and launch separate sessions of GHS All wizards are designed to be self explanatory All necessary documentation is built in or at least that is the intention There are no manuals or separate documents for wizards If you open a wizard file in a text viewer you will see that it is actually a Run File Some wizards use coded files that are not viewable because the programming in them is complex and we do not want to have to support versions that users have modified However you are free to write your own wizards for your own use or even to share with others All that is needed is some experience using macros variables and templates see the TEMPLATE command Some of the wizards that are distributed with GHS are updated frequently and they
8. 0 017 LOAD WT3 0 05 LOAD LUBE HYDR FW 0 10 82 9 0f 4 0f 1l 15 0 SYM 14 0 TIGHT 14 0 TIGHT NOWARN NOWARN MAX 12 0 NOWARN Creative Systems Inc www ghsport com GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com MACRO COND6 COND5 SUBTITLE Arrival no catch LOAD HOLD 0 MACRO CONDS 1 condition number 2 command to execute CONDZ1 PAGE 2 MACRO SHOW SOLVE STATUS GHS DISPLAY STATUS PROFILE PLAN MACRO DOCRIT LIMITS OFF HMMT OFF CRIT 1 IF S 2 lt gt THEN ALLCONDS CALC ELSE PAGE CALC MACRO ALLCONDS CONDS 651 wg SIM MACRO BYCRIT ALLCONDS SHOW DOCRIT NCRITS 1 1 ALL MACRO BYCOND ALLCONDS SHOW DOCRIT NCRITS 1 1 END Intact Stability with Three Criteria PROJECT INSTAB1 RUN FVSTAB LF CALL REPORT BOX BW Training Class Exercise Intact Stability VARIABLE NCRITS 3 MACRO CRITI LIMIT TITLE 170 173 UNITS LT LIMIT GM UPRIGHT gt 0 49 LIMIT RA AT ABS 30 OR MAX gt 0 66 LIMIT ABS ANGLE AT MAX gt 25 LIMIT AREA FROM ABS 0 TO ABS 30 gt 10 3 LIMIT AREA FROM ABS 0 TO ABS 40 OR FLD gt 16 9 LIMIT AREA FROM ABS 30 TO ABS 40 OR FLD gt 5 6 MACRO CALC SOLVE AN H ra L zi ca RA LIM ATT RUN C170170 LIB CALL MACRO CRIT2 UNITS LT SET P 0 005 MACRO CALC 170 170 MACRO CRIT3 UNITS LT WIND PRESSURE 0 005 ROLL IMO
9. Here are some things to observe 1 The reason we need to specify the Part and Component names is that the DXF does not carry this information 2 the 3D parameter must match that in the EXPORT command exactly i e it must accurately indicate the form in which the drawing portrays the 3D model and 3 the NOFILL parameter tells Model Converter to not bother with filling in extra stations since we know that it already had enough Finally add the second IMPORT command Of course if the drawing had contained other elements they could be similarly imported as additional Components of the hull as Sail class Parts and even as tank Parts but in most cases Part Maker is the best way to put tanks into the model After importing the geometry you will want to mark the deck edge Section Editor and Part Maker can do that as well but we will show how you can use Model Converter through the FIXUP command to accomplish this as well The command to mark the deck edge on HULL C would be FIXUP FV1 GF HULL HULL C DECKEDGE Your completed run file could look something like the following but without the SHELL command which is shown here to demonstrate what you could do if you had Rhino or some other CAD program on your computer and wanted to automate the step of examining a DXF before importing it PROJ MKHULL READ FV GF EXPORT HULLMHULL C HULL DXF 3D XYZ NOWAIT SHELL OPEN HULL DXF SPAWN 25 GHS Trainin
10. It is important that you understand the significance of having a separate working folder for each project Not only does it help to keep your files organized it also avoids having to specify paths with your file names The GHS Main Screen The various elements found on the GHS main screen are shown below Window bar program name and Project name if defined otherwise Geometry File name Menu bar pull down menus Title bar GHS Version Title as defined in Geometry File Project name Header with data box showing this data box can be turned off using the View menu Logo screen background shows the GHS logo can be changed via the View menu Display Command Area configurable via the View menu Status bar shows the working folder report file units setting Function Keys footer buttons Configurable via the KEY command TITLE if defined MENU BAR File Report View Project Macro Wizard Help PROJECT if defined GHS VERSION 7 BE NUMBER HEADER Values in equilibrium are in green Values not in equilibrium are in red LOGO defined by Fixed values are in magenta de SCREEN LOGOffilename DISPLAY area COMMAND area defaultis 5 lines Selected UNITS F NGHS Training Basi KEY assignments WORKING FOLDER H amp P SAVE wv EDI RUN F4 through F10 Pull Down Menus At the top of the GHS screen are several pull down menus Almost all of the activities that
11. a Definition Digitizer al m 5 Non GHS File m T Appendage a and Tank Run File rf o Definition Geometry Verification o 9 q Computations Run File rf z lt d O O Final Report Programs Or Or PM Part Maker DISPLAY Model Displays GHS FL LS etc Hydrostatic Computations Report Generator 11 SE Section Editor Hull Design Body Plan MC Model Converter Geometry File gf Stage 2 Intermediate Files Printed Output Geometry File gf Stage 1 Printed Lines and Offsets Finished Report GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Geometry Organization Understanding the Model Whether creating a GHS geometry file by importing an existing file or building one from scratch an understanding of the model hierarchy is required The essentials of the GHS geometry data structure are shown below in outline form it is fully described in an appendix of the GHS manual Note that there are three levels in the hierarchy At the highest level are the Parts Each Part has an unique name and belongs to one of three classes Displacer Parts providing the upward or buoyant forces Tank Parts providing downward forces Sail parts contributing only to wind heeling moments and not to buoyancy or weight Additional attributes of Parts are as shown below in the outline
12. apply to various aspects of these curves establishing metrics that relate to stability and safety There are several types of Limits and each type is designed to examine a certain quantity such as area or range of heel angles In most cases it is intervals between significant heel angles that are of interest The GHS keywords for some of the significant angles are EQU angle of stable equilibrium RAO angle of the second intercept or unstable equilibrium FLD angle of downflooding MAX angle at maximum righting arm ROLL angle after rolling to windward PRE angle before rolling to windward DI angle of deck immersion For the complete list see Help Limit The types of Limits are Angle limits these apply directly to significant angle ranges or values Area and Area Ratio these require some minimum area or ratio of areas Arm Arm Ratio and Arm Rise limits these look at righting arm levels at certain angles Gm limits these require minimum GM values 54 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com The RAH Command This command produces the righting arm curve in a particular load condition It is essential to almost all stability work If you accept the defaults and simply issue the RA command with no parameters you will get a reasonable result But if you have established a stability criterion with Limit commands you will need to include th
13. area curves derived from the sections are considered to be linear between the sections so the sections need to be spaced closely enough that the errors due to the linear approximations are negligible here as well You can experiment with point and section spacings observing the slight differences in results In most cases 25 35 sections gives acceptable accuracy Typically there is little if anything gained by using more than about 40 sections GHS enforces a maximum station spacing of 1 20 of the overall length Interpreting Shapes Note what the Component does It gives a particular interpretation to the points that comprise the Shape It also sets their final location on the vessel By this we mean the final curve you get from the points in a section will depend on the Side and Vector attributes of the Component If the Side is Starboard the points remain unchanged The last point connects to the first making a closed curve If the Side is Port the points are seen in their mirror image i e the transverse coordinates are negated and the order is reversed If the Side is Centerline the points are taken first to last then again from last to first with the transverse coordinates negated Thus the same Shape can serve both port and starboard Components and only half of a Centerline Component needs to be given The Purpose of the Hierarchy If you want to experience the full power of model building in GHS and avoid a lot of trouble
14. may require the latest versions of GHS At www ghsport com support downloads htm you will find links to the latest wizards for downloading them 53 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Most wizards involve more than one Run File There may be one or more library Run Files as well as the WIZxx file In any case when you get the file package copy all files into your GHS program folder User Variables and the SET Command User variables are similar to system variables But rather than providing information from inside the GHS program they hold information that you put there by means of the SET command This doesn t sound useful until you see what the SET command can do With it you can perform arithmetic calculations There are trig functions and many other handy functions that you can use to prepare parameters for other commands More on Limits and Stability Criteria GHS does not provide preset stability criterion options However using the LIMIT command you can define a stability criterion to be considered when performing an analysis The proper set of Limit commands will address known regulations But there are possible variations and interpretations of the regulations that are left up to the user s discretion Basically the Limits are about the righting arm curve the heeling arm curve and the residual righting arm curve which is the difference between the first two curves They
15. At the next level are the Components Components belong to Parts In other words each Part is the collection of its Components Since each Component belongs to only one Part Component names need be unique only within the Part Therefore when you refer to a particular Component it is helpful to mention the Part to which it belongs A complete Component reference is written as Parti Component Notice the back slash between the Part name and the Component name Part name optional description class substance Reference Point Sounding tube Definition optional for tanks only Component name side effectiveness or permeability factor adding vs deducting shape factor optional for sail or displacer parts only translation Vector margins optional Shape name shell thickness optional Section longitudinal coordinate and number of points Point transverse coordinate vertical coordinate longitudinal line code optional At the lowest level in the hierarchy are the Shapes This is where the bulk of the data resides The Shape is a 3 D solid model represented by sections where each section or station is a closed 2 D curve represented by a series of points The lines between points are straight therefore curves need to be represented using enough 12 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com points to make the errors in the linear approximations negligible Likewise the
16. BERE ded 50 Deadwelght 5 EE Db nobi coiere hieme teach ise tein 50 More on the Structure of Commands ssssssssssseseseeee eene nennen 51 Light Ship sinet 51 Adding Other Fixed Weights ccc ccceeceeseeeeeeeeeeeeeeeceeeeecaaeeeeaaeseeeeeseaeeesaaeeeeaaeseeeeeeenaaees 52 Finding Equilibrium sees ener nnne enne 52 Load Editor and LEW ecenin aniren N E E EA nennen nennen nenne nnne ener nennen 52 Iren EE 53 About Wizards oc aee Ire ce depe elit die eee envio elec Deae 53 User Variables and the SET Command ssssssssssseeeeeeeen nennen 54 More on Limits and Stability Criteria esses 54 The RAH Commandin elie ie dates DU obi eerie d Ee 55 Heeling MOmento 56 Wind Fleelirig 1 2 eiee N aE aN E EE a e Dea DE a N dde 56 Severe Wind and Rolling Calculations sssssssesseeeeeeeeen nennen 57 More about FSM dci inet oep anteire ep Ere tials Heec irte Edge etait tela 59 An Intact Stability Exercise essessseessseseseeeeseess einen entente nn nant Ea TE nnn nnns 60 Longitudinal Strengths ia certet eit ee rni ee ia tte doa n tr exhi dana 68 An L S EX6ICISO ectetur eee eom etin t odia Relies iG 69 Floodable b engtlis in emen geehrte n Ble ates 70 Report Optioris hoe e hom ete eben eet de tdmen 71 Special Message Commands sse
17. Departing fishing grounds good catch Stores 4 0 14f 0 15 0 WT2 0 05 LUBE S 0 33 HYDR P 0 33 FW 0 33 HOLD 1 0 Depart fishing grounds no catch holds empty Arrival good catch Stores 0 2 l4f 0 15 0 WT3 0 05 LUBE S 0 10 HYDR P 0 10 FW 0 1 0 HOLD 1 0 Arrival no catch holds empty 61 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Intact Stability Exercise specification continued The CFR 170 173 criterion requires several Limit commands See the highlighted portion of the regulation text Reference HELP LIMIT for the Limit commands This criterion is easily addressed with a simple RA LIM starting from upright heel The CFR 170 170 weather criterion appears to have been formulated as a simplification of a criterion that limits the angle of wind heeling by requiring a minimum GM There is a discussion of this in the GHS User Bulletin WEATHER HTM which is on ghsport com A way to address the criterion is presented there but it does not meet the letter of the law Therefore it is recommended that the C170170 macro library be used Here are the steps after setting up the load condition RUN C170170 LIB CALL SET P 0 005 170 170 For all three criteria Calculations to be performed using CG shifts Report to include subtitles Status with GM amp Critical Point heights and righting arm data with evaluation of each stability criterion with grap
18. Exercise ssssssssssssess esent ensis tette nnns 24 Deck Edge Considerations ttt eet e eter ete de dense 26 Another Model Converter Exercise sssssssssssssseeeeeene enne enne nnns 26 Getting Into Part Maker te rete eee et eet ete denda 27 A Part Maker Exercise rie nett eer ei eet le te e ent 28 Generating Report Sade nitear eee ep e dte ente e abend 30 The Basic Run File Structure for Reports ssssssseeeneenenneneenns 30 Annotating RuttiFHles ccce e etit na eel nt ede 30 Printing Out the Geomllry ined n teen eee teile de 30 Annotatirigi REDS s cte de io el ae dee bt eer dl etg o re ru adc 31 The MESSAGE GComtrriand ttt ete Getae edu ttd 31 System Variables te Eee ere ek whi aie elcid 31 Two Kinds of Cale lati ris i tree e te pe nt Eee 32 Parts and Components in the Calculations essssseeeneeeneneen ns 32 Reference Points of Parts eeeesssseseiseseseseeee ennemi nenn tren nennen entren 32 The G rrent Parts EISE iid tere iege PD p ade flc Pe eite 33 Heel Angles and Trim Angles sssssssssseeeeennenenen mener nne 33 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Origin Depthr vs Drafti isien ec oett t a edd nce eb exe rei be nd nee ine e 34 P AP and EBB ie i eae pe tete ea pda eec te prie bett i tins 35 Trim Angle vs Trim DIStare9 exiit p De
19. LIMIT TITLE IMO SWR LIMIT RES RATIO FROM ROLL TO ABS 50 OR FLD gt 1 83 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com LIMIT ABS ANGLE AT PRE 16 LIMIT ANGLE FROM PRE TO 80 DIO gt 0 MACRO CALC HMMT OFF SOLVE ANGLES HMMT WIND CONST GUST 1 5 TRIMALLOW HMMT SOLVE HEEL ROLL RA LIM ATT GRAPH CLEAN PE BYCRIT All conditions for each criterion BYCOND All criteria for each condition REPORT PREVIEW REPORT OFF END Damage Stability PROJECT DASTAB1 RUN FVSTAB LF CALL REPORT BOX BW fraining Class Exercises Damage Stability VARIABLE NCRITS 1 MACRO CRITI LIMIT TITLE DAMAGE STABILITY UNITS LT LIMIT ABS ANGLE AT EQU lt 7 LIMIT ANGLE FROM EQU TO DI gt 0 LIMIT AREA FROM EQU TO ABS 30 OR FLD gt 10 0 MACRO CALC SOLVE ANGLES HEEL 0 LIM ATT MACRO DODAM TYPE INTACT QUIET TYPE 1 FLOOD BYCRIT All conditions for each criterion BYCOND All criteria for each condition DODAM ENGRM C LUBE S FODAY S DODAM WT2 S DB1 S REPORT PREVIEW REPORT OFF END 84
20. The surface attitude in a loaded tank automatically follows the heel and trim angles of the external waterplane so that the center of gravity is recalculated each time the inclination changes This is how GHS represents free surface It is something like a moment of transference method We call it simply CG shifts in tanks and it gives similar results As in the TYPE command presented earlier tankname in the LOAD command can be a list of tanks and the asterisk wildcard can appear at the end of any of those names Coefficients of Form Wetted Surface and Sectional Area Curves These calculations all apply to single Components and therefore come under the COMPONENT command They differ from the COMPONENT commands covered earlier in that they are based on current waterplanes If the Component belongs to a Hull or Sail class part or a tank in flooded mode its waterplane is the external waterplane of the vessel If the Component belongs to an intact tank its waterplane is the surface of the liquid in the tank COMP FORM produces coefficients of form for Parts in the Current Part list or if the Current Part list is empty it does it for all Components of all Parts including tanks COMP HULL HULL C FORM produces the coefficients of form for the HULL HULL C component COMP HULL HULL C SECTIONS produces station section properties COMP HULL HULL C WETTED is like FORM wit
21. and confusion then take the time to understand the Part Component Shape hierarchy There are good reasons for this structure When you finally produce a report showing vessel loading conditions the report will list the Parts only This is a great feature because it allows you to build up a complex hull or tank compartment using many Components yet the report will show only the summation of all Components belonging to the Part So the purpose in having Components within Parts is to make the construction of the model easier without having unnecessary detail in the final report Then why have an additional level for Shapes Because you can use a Shape in more than one place How is that possible if two objects are not to be occupying the same space What makes it possible is the translation Vector at the Component level Each Component points to or we might say it is used by one and only one Shape But a Shape can be used by any number of Components since a Component can vector the Shape to a position that is suitable to its own purposes The most common use of this is where symmetrical port and starboard Tank Parts have Components that share the same Shape In this case the translation Vector is not even needed since the 13 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Component can also use the Shape as its mirror image simply by designating its Side as Port or Starboard as noted above It is w
22. component shape information on lt off CTRL P part toggle entire part lt gt single component Zoom CTRL F9 centers cursor on selected point F9 restore normal view entire part fills screen F10 zoom in Z ZOOM zoom by a sets the zoom factor default is 1 0 which doesn t change the scale but does center the cursor on selected point Change selected part SPACE cycles through parts PAGE DOWN selects next part PAGE UP selects previous part Change selected component down arrow selects next component in present part 1 up arrow selects previous component in present part Change selected station F7 more to next station aft in shape F8 move to previous station forward in shape CTRL F7 move to last station is shape CTRL F8 move to first station in shape Change selected point F5 move to prior point on station F6 move to next point on station CTRL F5 move to first point on station CTRL F6 move to last point on station See following page for SE Editing Commands 22 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Section Editor Only Editing Commands Note Section Editor uses only the first letter of a command Once the first letter is typed the command becomes active Additional letters typed are perceived by the program as input to the command See HELP SE REF for more details about Section Editor commands and functions Input Mode Keys F
23. dummy parameter since it simply reserves the place where the real parameter will be substituted when the macro is executed In this example the macro T is executed three times In the first execution the TRIM command becomes TRIMz1f In other words it sets the trim to 1 0 LBP forward Up to nine different dummy parameters can be used i e 1 962 etc Nested Run Files Another way to encapsulate a series of commands to be used later is to have them reside on a separate Run File At some point in your master Run File you would use the RUN command to run the separate file The command processor then begins taking commands from that file until it comes to its end or encounters the END command Then it may or may not revert to the next command in your master Run File depending on the form of the Run command For example if you have within your Run File the commands RUN MORE RF MESSAGE Back from More and continuing it will process the commands from MORE RF but will not return to process the Message command The way to make it return and keep going is to include the parameter CALL with the RUN command For example RUN MORE RF CALL MESSAGE Back from More and continuing will return and continue processing the Message command If you develop a general purpose Run File the place to put it would be in your User Library folder so that it becomes easily accessible from any working folder A word
24. eene nennen nnns nennen 73 Tank Characteristics ae eine e edt Abas Dresd ata da eee 74 Tank Characteristics ExXerCiS Ginie is mesara aa aa entrent eene enne 74 Tank Sounding Tables etm red cet emendet p e eur ere een 74 Damage Stabllity 1 cite mb teet e icri i n patte Ada tts 75 A Damage Stability EXerci Se mieness eani aaea a aa esee entente entree 75 Tonnage Calculations e ane an ean eaa rene tee te eb e ie en er aa e fee 75 SKIN ALCAS oendaa ee tedden HE e Doe i tere Ep eet eee gad see eet aes 75 Important WIZards erret eee ied ad e Ete ee gens pcr ee EE Ree 76 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Introduction The GHS software is primarily for ship stability and strength in view of regulatory standards But it is also well suited to simulating the behavior of any body floating or not where ground reactions and other forces may be present It is often used in simulation oriented settings such as salvage crane ships and heavy lift operations to name a few It also has an on board configuration known variously as GHS Load Monitor GHS LM or simply GLM where it becomes an efficient electronic stability book that naval architects provide for their clients augmenting the traditional paper T amp S books GHS derives nearly all of its results directly from 3 dimensional geometry models of the ship hull and its interior arrangements This is unlike some competing softwar
25. expect that locations refer to an origin they are familiar with The origin appears as a blue crosshair in Section Editor Display and the vessel graphic when it is displayed in the background of the GHS main screen 14 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Waterplane Coordinates The following illustration emphasizes that the vessel coordinate system is attached to the ship Centers of gravity and centers of buoyancy are always with respect to the ship coordinate system However the direction of buoyant and weight forces is perpendicular to the waterplane which is only parallel to the baseplane when the ship is upright At equilibrium the CB center of buoyancy and the CG center of gravity are on a line perpendicular to the waterplane If heel or trim are present this line will not be vertical in the vessel coordinate system Therefore you can expect to see a difference in the longitudinal and transverse coordinates of the CB and the CG even at equilibrium This is illustrated in the bottom diagram Coordinate System Diagrams Positive Upward om ae oa Positive Coordinates Aft Negative Coordinates Forward The Longitudinal and Vertical Axes Profile View Positive Upward Origin Point Baseline Negative to Port Positive to Starboard The Transverse and Vertical Axes Body View Looking Forward Note All dimension
26. for intact stability apply to damage stability as well The only difference is that one or more tanks compartments will have TYPE FLOODED This is the only tank type that is used in regular damage stability work TYPE DAMAGED is reserved for special simulations since it requires a specific point of damage A Damage Stability Exercise For the loading used in the intact stability exercise determine if the fishing vessel meets the following criterion Angle at equilibrium less than 7 degrees No deck immersion Can the margin line be immersed DI vs DIO Righting energy to the lesser of 30 degree or flood is greater than 10 ft deg Check these two damage cases Engine room starboard LUBE and starboard FODAY tanks flooded Starboard WT2 and DB1 tanks flooded Tonnage Calculations A report that is useful for International Tonnage is available through the COMPONENT command COMPONENT TONNAGE Skin Areas Skin Area of any component is now available beginning with GHS version 12 28 through COMPONENT SKIN This calculation was previously available in the optional SA module and is now included in the main program Skin areas are useful for estimating hull materials plating weight and CG and areas for painting 76 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Important Wizards Some areas of GHS application are best done with wizards because the sophistication of the Run Files require
27. get the bare bones version that is still fully capable of editing loads both in tanks and your added weights 52 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Inclining Setting up for an inclining calculation is much like the setup we did for the light ship solving earlier Of course in that case we somehow knew the VCG In the inclining calculation we re trying to find the VCG as well as light ship weight and the other components of its CG However setting up the waterplane setting any tank loads and other loads such as inclining weights that are aboard and not to be included in light ship is all the same No doubt the DRAFT command will be more elaborate more like what we saw earlier when the DRAFT command was first introduced listing several drafts taken at different locations and expecting it to result in some deflection Having done all that the final step is to use the GMTMMT command which takes as a parameter the GM moment This is the slope of the righting moment curve that you derive during the inclining experiment Help GMTMMT has an example which if it has a WAVE command and does not include the DRAFT command with more than two drafts is dated When you provide at least three drafts you do not need to simulate deflection with a WAVE command However in other respects it is a useful example The easy way to do the inclining calculations is to use the Incline wizard You will find
28. iso body mode Shift Tab will toggle between the profile and plan views or the iso and body views To go from Part to Part press the Page Up and Page Down keys It cycles back to the first part after the last part To go from Component to Component within the same Part use the Up arrow and Down arrow keys Note that on the left side of the screen there is a vertical array of Function Key reminders Pressing F1 on the keyboard not the screen will bring up the complete Section Editor usage information Go to the end of it and you will find a handy alphabetical list of the SE commands Commands in SE all begin with different letters of the alphabet When you type the first letter of a command the rest of the command word appears automatically This action is unique to Section Editor and its derivative DISPLAY A Section Editor Exercise As an exercise try to create the geometry model shown below using Section Editor The finished Geometry File will have two Parts a Hull class Part and a Sail class Part in this case the Sail Part is actually a sail If you are now in Section Editor and there is some geometry showing give the command Read clear to get ready to create the new model When there is no geometry in Section Editor it goes directly to the body view screen so that you can begin entering points immediately You can declare the name of the Part and Component now or you can do it later Let s do it now We will be naming the hull 1
29. measurements The rolling period TR in s is calculated as follows where The symbols in the tables and formula for the rolling period are defined as follows LW Length in m of the ship at the waterline T1 Mean moulded draught in m of the ship AK Total overall area in m2 of bilge keels or area of the lateral projection of the bar keel or sum of these areas or area of the lateral projection of any hull appendages generating added mass during ship roll GM Metacentric height in m corrected for free surface effect 4 Effects of free surfaces of liquids in tanks 4 1 General 66 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com 4 1 1 For all loading conditions the initial metacentric height and the righting lever curve are to be corrected for the effect of free surfaces of liquids in tanks 4 2 Consideration of free surface effects 4 2 1 Free surface effects are to be considered whenever the filling level in a tank is less than 9876 of full condition Free surface effects need not be considered where a tank is nominally full i e filling level is 9876 or above Free surface effects for small tanks may be ignored under the condition in 4 9 1 4 2 2 For ships having cargo tanks with a breadth greater than 60 of the ship s maximum beam the free surface effects when the tanks are filled at 98 or above may not be neglected 4 3 Categories of tanks 4 3 1 Tanks which are taken i
30. more than a simple sequential list For example there is the IF command which enables you to execute some commands and not others under certain conditions These special commands are powerful and they allow you to do many things that you might not expect would be possible in this type of program In fact GHS can be used as a general purpose programming platform There is even a special version called GHSOS for GHS Operating System that includes the command language without the ship stability functions The Complete GHS Optional Modules During the training course you will have access to the complete set of GHS modules But since some of these modules are optional it is possible that you will not find all of them in your own particular GHS configuration All GHS systems include the essential model building tools Section Editor SE Model Converter MC and Part Maker PM and the essential set of calculations with their reports including both intact and damage stability The optional modules are Condition Graphics CG displays vessel and tank loads graphically on screen and in reports highly recommended Load Editor LE and Load Editor with windows LEw for interactive load management Longitudinal Strength LS computes shear bending deflection and torque curves Floodable Lengths FL produces floodable length curves Tank Soundings TS computes and prints special tank sounding tables
31. of structure and loads that have fixed magnitudes and positions on the ship Therefore we divide the weight items into Fixed weights and Tank weights meaning the the weights and centers of tank contents which implies that Tank weights are variable at least in the locations of their centers Here is the issue Fixed weights including light ship weight and its center are represented in Commands that reside in Run Files So we have two kinds of files Geometry Files and Run Files Talking to GHS Commands Run Files and Reports GHS is a command oriented program All of the input data all of the information you provide that is not in the Geometry File is in the form of commands A command as we have already noted can provide such things as Fixed weight items Commands also instruct the program about what you want to do with the model A fundamental and important concept is that commands are processed as sequential steps and the order in which commands are given can be very significant The program processes commands one at a time Every time a command is processed the program takes some action and in many cases the state of the program is changed as a result This is actually a very familiar paradigm that we see all around us everything and everyone reacts to sequential inputs and at any given moment is the result of the history of those inputs Many people today have trouble understanding sequential processing because of the
32. overall model length Section Editor will write a geometry file even if the station spacing is too large in which case a Station spacing too great error will appear when trying to read the file into GHS main memory If this happens you can immediately give the main program s FILL command and it will send the Geometry File through Model Converter FIXUP to fill in the missing stations But we can easily generate the missing stations with the Fill command in SE before we leave Note that this filling operation whether done by SE or MC uses nonlinear interpolation It will detect obvious abrupt changes in the original and use linear interpolation in such cases However it is not a bad idea to put closely spaced stations at any discontinuity before Filling In the case at hand the Fill operation should respect the knuckle and give reasonable results from just the three original stations Making the Sail To complete the model in this exercise Enter the Name command again and instead of accepting the default prompt HULL enter Name sail rigNsail c The SAIL prefix tells SE that it is to be a Sail class Part It will come back asking Want to create part RIG This is to guard against accidentally starting a new Part when you 20 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com only wanted to switch to an existing Part In this case we do want to start a new Part so the answer is Yes The r
33. reports Similarly nearly all of the commands in the GHS main program deal with whole Parts For the most part the user need not be aware of the Components within the Parts The exception to this is the COMPONENT command This is the only command that produces reports based on individual Components There are three uses for this One is to get component properties coefficients of form curves of form wetted surface and skin surface area The second use is setting those component parameters that are adjustable permeability effectiveness and shape factor The third use is delving into the Component level to investigate how individual Components contribute to the properties of Parts This can be carried even further down to the section level examining section properties and sectional area curves Reference Points of Parts One of the attributes of a Part is its Reference Point Each Part has a Reference Point attached to it which can be set and reset at any time This point is used for various purposes Usually it marks some special point on the Part However the initial default setting of Reference Points on all Parts is 0 0 0 i e the same as the origin of the coordinate system Any Reference Point can be set to any location by means of a statement in Part Maker at the time the Part is created and that setting is kept in the Geometry File Reference points can also be changed at any time in the main program by means of the REFPT command F
34. respect to the current heel angle if the vessel is inclined be sure to set heel before draft Draft Surveys Deadweight surveys inclining surveys and salvage surveys all depend on being able to model a waterplane that accurately represents the survey condition Heel angle is straightforward If the heel is not great the multi point drafts could be used to establish 46 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com both the trim and the origin depth Of course freeboards would have to be converted to drafts before they could be used If the heel angle is large such as in a salvage situation it might be more convenient to set the trim as an angle and set the origin depth indirectly through the HEIGHT command The HEIGHT command references a particular critical point You would set up a critical point at some convenient point then take a plumb line measurement to the water surface from there This would be the height of that point above the waterplane The command to reference critical point 21 where the height is 5 43 would be HEIGHT 21 5 43 Tank Loads In order to make use of your tank geometry tanks can be loaded up to specified levels The LOAD command is used for this For example LOAD tankname 0 98 sets the surface in the tank such that the volume is at 98 of the tank s capacity There are many other ways to specify tank loads via soundings and ullages for example
35. standard conditions of loading as set out in Ch 3 App 2 1 2 Figure 1 Severe wind and rolling Angle of heel 3 2 2 Criteria Under the assumptions of 3 2 1 the following criteria are to be complied with the area b is to be equal to or greater than area a where a Area above the GZ curve and below w2 between OR and the intersection of w2 with the GZ curve b Area above the heeling lever w2 and below the GZ curve between the intersection of w2 with the GZ curve and 02 the angle of heel under action of steady wind 00 is to be limited to 16 or 80 of the angle of deck edge immersion whichever is less 3 2 3 Heeling levers The wind heeling levers w1 and w2 in m referred to in 3 2 2 are constant values at all angles of inclination and are to be calculated as follows EAE WB 1000gA and Pus 1 5 05 65 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com where P 504 N m2 for unrestricted navigation notation The value of P used for ships with restricted navigation notation may be reduced subject to the approval of the Society A Projected lateral area in m2 of the portion of the ship and deck cargo above the waterline Z Vertical distance in m from the center of A to the center of the underwater lateral area or approximately to a point at one half the draught A Displacement in t 79 81 m s2 3 2 4 Angles of heel For the purpos
36. such as tank volumes and sounding ullages See Help TC for the full range of options Tank Characteristics Exercise Starting with the Run File listed below add statements to produce additional tank characteristics reports for DBO S and DB1 S giving volume in gallons and no surface information WT1 S and WT2 S using tank soundings and no load fractions PROJECT TC1 READ FV GF REPORT TC HOLD1 C 1 2 1 NOREF VOLUME GA TC WT2 S SO 0 25 12 NOREF REPORT PREVIEW REPORT OFF Tank Sounding Tables The TS command produces several formats of detailed tank soundings tables that are designed for everyday shipboard use Included are the following 1 Volume vs Sounding arranged four columns per row default 2 Volume vs Sounding amp Ullage in Ft amp Inches or M amp Decimeters 3 Volume Cu Ft M Center amp Moments vs Sounding 4 Volume Cu Ft M Center Trim Corr amp Transverse Moment vs Sounding 75 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com 5 Cu Ft M Volume amp Weight vs Sounding amp Ullage 6 Volume Cu Ft M Weight Center amp FSM vs Sounding A report file must be open since these reports have no screen only counterparts Example ROJECT TSOUND EAD FV GF EPORT S WT1 S FORMAT 1 EPORT PREVIEW EPORT OFF eU ori uu Damage Stability All of the commands and methods used
37. the IMO criterion for severe wind and rolling If the PRE angle keyword appears in a Limit it refers to the heel angle which was current immediately prior to ROLL For example LIMIT ANGL E FROM PR E TO ABS 16 OR 80 DI0 gt 0 expresses the limitation on the angle of heel under the action of steady wind from the IMO criterion for severe wind and rolling In this case a SOLVE must preceed the windward roll in order to ensure that PRE refers to equilibrium with the non gust heeling moment When you want to run the righting arm curve either to port or starboard depending on the vessel s initial non wind list things get a little more complicated The MAXVCG 58 GHS Training Book Standard Course Rev 07 15 Creative Systems Inc www ghsport com process handles this automatically but when you are doing an individual righting arm curve you have to make sure that certain commands are in the correct order The procedure is as follows 1 With the heeling moment off solve for the equilibrium heel angle 2 Set the ANGLES direction accordingly 3 Set the heeling moment 4 Set the HMMT direction according to the heel angle 5 Solve for the equilibrium heel with steady wind 6 Apply the roll 7 Do the RA LIM command Here is an example MMT OFF LVE GLES no UH MT IL h I 3 a iV EEL ROLL A LIM o More about FSM O N MMT WIND CONS
38. 2 edit mode toggle insert replace move CTRL F2 toggle key edit mode o insert replace mode see K command below Commands for editing geometry A Arc converts present point to an arc of specified radius F3 duplicate present point F4 delete present point CTRL F4 delete present station D Delete delete component if only one component deletes the part also E Edit edit the component vector effectiveness factor or margin F Fill interpolate stations on the present shape to fill gaps larger than given interval K Keyedit toggle keyedit mode enabling arrow keys to nudge selected point ARROW keys ft nudge point by 0 010 CTRL ARROW moves larger increments 0 100 L Location move present station can be used lengthen or shorten vessel N Name select create new or rename a part component S Station new station copy present station or interpolate new station X Xlate toggles translate mode moving a single point moves entire station CTRL D construct deck edge CTRL Z deconstruct deck edge CTRL U Undo CTRL R Redo Other commands F1 help window Q Quit to exit section editor will prompt to save changes R Read read a geometry file if already read in GHS will be read automatically T Title to add a title to the geometry file U Units to set units for input and display W Write saves the current geometry to a file 23 GHS Training Book Creative
39. 5 www ghsport com The STATUS DEADWEIGHT report shows Deadweight Loaded which is simply the sum of added weight items and tank loads above light ship You can get this report without the displacement information STATUS WEIGHT DEADWEIGHT More on the Structure of Commands As we get into writing more extensive run files it will be helpful to revisit the topic of command structure and to carry it farther Let s look at two examples ADD Crew and effects 12 34 425 f 0 0 15 5 LOAD FO STATUS ULLAGE VOLUME BB The primary parameters appear immediately after the command name and sometimes their order is important If the first parameter is optional it is enclosed in parentheses to make sure that the program has no trouble determining whether or not it is present After the primary parameters there may be slash parameters that are almost always optional and have no particular order requirement A parameter might have one or more sub parameters In the example above BB is a sub parameter As you can see in the above examples parameters are often numbers Sometimes they are strings of characters enclosed in quotation marks And sometimes they are keywords When a command line ends in either a comma or a semicolon it is considered to be incomplete and the next line is appended to it For example ADD Deck cargo 0 23 20f 0 67 10f 0 67 Q 8f 00 L7 5 This is considered to be all one command You
40. 7 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Part HULL and its single Component will be HULL C the C meaning it will be a Centerline component so that we will only need to create the starboard half to get the complete symmetrical hull Enter Name hul1 hul11 c to provide this information Actually HULL HULL C is the default and you only needed to press N then the Enter key Notice these names appearing at the top of the screen You will also notice that the Shape has been named automatically as HULL About Names of Parts Components and Shapes Part and Component names look about the same Both are limited to 14 characters and must have no embedded spaces Component names carry a Side designation by means of the suffix S P or C Tank Part names generally carry a side designation in the same way but other Part names do not Hull class and Sail class parts do not have this side suffix Although the side suffix is available on Tank Part names it is the Components that actually determine how each Shape is interpreted and whether it goes on the port or starboard side as explained previously Shape names are limited to eight characters and obviously do not need side designations since that information is provided at the Component level Most of the time you will not be concerned with Shape names since the system will assign them
41. GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Table of Contents WTOC UCTIO Ne n beh bey 3 The P rpose ofthis Docume ssni eenaa eie idet e tut ht na 3 First the Geomelry File tette eh ehe haa eh eo e ko E RR ER ERRANT EE RENE AERE RE 4 The Rest of the Model Fixed Weights vs Tank Loads see 4 Talking to GHS Commands Run Files and Reports sse 4 The GHS Command Language sse enne en nennen nsns 5 The Complete GHS Optional Modules sssssssssesseeeneneeeen nnne 5 Installation and Setup ssssssssssssseseee enne enne tnn nnn rentes nensi nnns entre ada nns 6 Starting Up the Program ssssssssssssseseeeee eene enne nensi nnn intres en res nnns nennen 6 The GHS Main Screen sssssssssssssssssssss eene n nennen entree nennen nsns sn nnne nn nenas 7 PulEDown Men s nerit ie eie idit 7 celo 8 Text efo ogest iU jo 8 The User Library Folder erogate ea ean NIKA ARA TAAA KANAA RAE nennen rA ia ARANETA tenen entere nnns 8 The Executive Dialog BOX rrara riidt arapo vaaia neika AAA aE EAR AAK EA Pait A Reak AATda R banda RiT KAARE 8 Automatic Start up Run Files sess en nennen nnne 9 DirecbCommarnd ETntty esie ttt os ust Lon uA Er 9 The Structure of Commands asise ra aa a aa a enini nennen nennen 9 Changing the Working Folder
42. If there happens to be a TIGHT point that is submerged as the vessel sits at equilibrium the stability is considered to be failing in that case also Curves of Maximum VCG The MAXVCG command produces these curves and the independent parameter is draft or displacement weight just like we saw in the GHS and CC commands In addition the MAXVCG command will take a list of trims or LCG values so that you can get a family of curves where each curve represents the highest VCG that meets the current Limits at each given initial trim or LCG There must have been one or more Limit commands issued to establish a stability criterion before the MAXVCG command is issued The process which GHS uses to find maximum VCG values involves generating righting arm curves and evaluating their characteristics according to the Limits in effect The VCG is experimentally elevated until it reaches the point where one of the Limits is exceeded The report that is generated shows the result of evaluating each of the Limits at the maximum VCG These are shown as margins relative to the Limit value If everything goes well at least one of the margins will be zero and the others positive The Limit with the zero margin is the one that limited the VCG at that displacement If the program finds that no matter how low it makes the VCG one or more of the Limits are still negative it will not show a maximum VCG result in that case The most common cause of this is early downfl
43. L CONVERTER FROM BARGE DXF COMM TANKS ADDED PER TANK DWG REATE HULLNTUNNEL C DEDUCT C FIT HULL CREATE HULL SKEG C ENDS 34 39 TOP 4 BOT 0 IN 4 OUT 5 FIT HULL CREATE REMAINING TANKS PER SKETCH Q REATE TANK SNC1 S ENDS 13 16 N 1 OUT 3 TOP 4 FIT HULL COMP LOCUS 19 1 1 FIT HULL JOIN C1 S CREATE TANK P C1 P ENDS 13 19 N 1 OUT 7 TOP 4 FIT HULL DEDUCT C2 P ENDS 13 16 N 3 OUT 7 TOP 4 BOT 0 SPACING 1 EDUCT C3 P ENDS 16 19 IN 5 OUT 7 TOP 4 BOT 2 SPACING 1 I Q REATE VOID1 S ENDS 0 10 XL I2 8 0 2 5 8 8 2 5 2 LOCUS 16 1 1 7 1 7 2 5 2 7 2 5 2 80 Creative Systems Inc www ghsport com GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com FIT HULL CREATE VOID1 P OPP VOID1 S A CREATE VOID2 S ENDS 10 21 FIT HULL DEDUCT SHAPE TANK S C1 S CREATE VOID2 P ENDS 10 21 FIT HULL DEDUCT SHAPE TANK P C1 P COMP SHAPE TANK P C2 P COMP SHAPE TANK P C3 P CREATE VOID3 S CREATE VOID3 P CREATE VOID4 S ENDS 32 40 FIT HULL CREATE VOID4 P OPP VOID4 S CREATE WELL P ENDS 26 32 INB 2 OUT 4 FIT HULL mS NITS M RITE BARGE GF1 ISPLAY CHO OFF ESSAGE Except for VOID3 P amp S volumes should match AIT UIT PM SMAHUaG D z A ca O Composite Max VCG PROJ MAXVCG2 READ FV GF REPOR
44. Mi i H i d EET wt S we QR ge ra L4 3 9 Perspective CREATE THE TANKS IN THE SAMPLE BARGE USING ADDING OR DEDUCTING COMPONENTS USE BOTH METHODS IF TIME PERMITS CREATE CHAMFER BY FIT TO HULL HOW MANY COMPONENTS ARE REQUIRED FOR EACH METHOD WHAT EFFECT DOES JOINING THE COMPONENTS HAVE CAN THE LOCUS COMMAND BE USED TO CREATE THESE TANKS IF SO HOW MANY LOCUS STATMENTS ARE NEEDED 29 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Generating Reports In order to generate a report you need to open a report file to receive information The REPORT filename command is used for this From the time GHS receives the REPORT command to open a file until the time it gets a REPORT OFF command to close the report file you will be capturing a record of anything displayable that issues from your commands At any time while a report is open the command PRINT PREVIEW or REPORT PREVIEW will bring up a window allowing you to see the report as it would look if it were printed The preferred and default file name extension for report files is PF Through the Report menu you can View text only and Preview text and graphics report files The Basic Run File Structure for Reports So far we have made Run Files that are oriented toward creating geometry From this point on we will be using the geometry that was created previously and our Run Files will be structured accordi
45. OMPOSITE parameter In all other respects the MAXVCG commands must be identical Sounds like a good place to use a macro Oh yes there is another thing When doing composites at more than one initial trim use the LCG option rather than giving trims directly The reason for this requirement is that the internal organization of the maximum VCG data uses LCG and displacement Trim depends on the VCG itself while LCG does not A Exercise in Composite Max VCG For the same range as above create composite Maximum VCG curves based on the two criteria shown above The plan of this Run File would be Project Read Define critical point 2 Report Criterion 1 Maxvcg Criterion 2 Maxvcg COMPOSITE WRITE MAXVCG MAXVCG DAT Preview Report off This is only a plan for the run file not actual commands except the WRITE command which can appear exactly as it is written What it does is write a special Run File that contains all of the maximum VCG information that was being held within the program at that point This will save you from having to rerun the original MAXVCG calculations when you want to make use of these particular max VCG curves 44 GHS Training Book Standard Course Rev 07 15 Creative Systems Inc www ghsport com When you get this exercise up and running you will notice that it appears that the second MAXVCG report is independent of the first one Each one is reporting the results of the particular crit
46. Systems Inc Standard Course Rev 07 15 www ghsport com Model Converter Importing and Exporting Geometry Model Converter is used when you import or export geometry data The IMPORT and EXPORT commands are most useful for these operations and when you use these commands you are actually using Model Converter indirectly The DXF drawing file is one source of geometry data that the IMPORT command recognizes For example if you have a CAD drawing and can export the hull sections as a DXF you can then import the data from the DXF into a GHS Geometry File It is recommended that the data in the DXF be in the form of a 3D drawing Model Converter will also handle 2D drawings but it becomes more complicated since section locations have to be communicated explicitly Model Converter offers you several ways to do this such as using layer numbers or names to represent the longitudinal location of the section on that layer Since the DXF file fundamentally represents a drawing there is no guarantee that a coherent model can be extracted from it For example there is nothing to prevent the DXF from having lines that are coincident Model Converter must piece together line segments polylines and arcs from the DXF in order to make a 3D solid model suitable for the GHS Geometry File The DXF file format does not require that these drawing elements be in any particular order even if it is a 3D drawing A Model Converter Exercise For this exercise we
47. T CRTPT 2 Focsle door 23f 8 0 14 0 UNITS LT LIMIT 1 AREA FROM 0 TO 30 gt 10 3 LIMIT 2 AREA FROM 0 TO 40 OR FLD gt 16 9 LIMIT 3 AREA FROM 30 TO 40 OR FLD 5 6 81 GHS Training Book Standard Course Rev 07 15 MACRO MV MAXVCG DISPL 50 100 250 LCG MV LIMIT 1 GM UPRIGHT 0 49 LIMIT 2 RA AT 30 OR MAX 0 66 LIMIT 3 ANGLE AT MAX 25 MV COMPOSITE WRITE MAXVCG MAXVCG DAT MV LOOKUP REPORT PREVIEW REPORT OFF END Load Condition Setup Library File FVSTAB LF FV Stability Load Condition Setup Library READ FV GF UNITS LT WEIGHT 156 0 0 56f CRTPT 1 ER VENTS CRTPT 2 PORT CABIN DOOR CRTPT 3 STBD CABIN DOOR 0 10 56 22 8 10 0 5 0a 7 0s 9 0p 9 0Ss MACRO COND1 SUBTITLE Departure UNITS LT ADD Crew effects ADD Stores ADD Net on deck LOAD O QUIET LOAD WT FODAY LUBE HYDR 0 LOAD FW 0 98 LOAD HOLD 0 0 MACRO COND2 COND1 SUBTITLE Arrival at fishing grounds LOAD Stores 0 66 LOAD WT1 0 05 LOAD LUBE HYDR FW MACRO COND3 COND2 SUBTITLE Departing fishing grounds good catch LOAD Stores 0 33 LOAD WT2 0 05 LOAD LUBE HYDR FW LOAD HOLD 1 0 MACRO COND4 COND3 SUBTITLE Depart fishing grounds no catch LOAD HOLD O0 25 0 15 0 13 0 2 0 25 12 0 14f 5 0 20a 95 0 66 0 33 MACRO COND5 COND3 SUBTITLE Arrival good catch LOAD Stores
48. T GUST 1 5 TRIMALLOW M O The only way to prevent GHS from recalculating the centers of gravity in tanks is to Freeze the tanks contents TYP E FROZI EN However you can have it temporarily suspend the CG shifting during righting arm curve calculations by including the FSM parameter with the RA command That causes it to temporarily freeze the tanks and to compensate by elevating the overall center of gravity according to a free surface moment After we have decided what the total FSM number is in a given load condition the next thing is to decide when to freeze the tanks 1 at zero heel and trim 2 at zero heel and equilibrium trim 3 at equilibrium with the CG elevated 4 at normal equilibrium 5 at equilibrium before or after wind heeling Communicating your choice here is intended to be a natural result of your preparation before the RA command Finally we have to decide in which direction to move the CG If it is elevated at some angle other than equilibrium it will change the angle of equilibrium Should it be elevated at the same heel and trim at which the tanks are frozen This can make a substantial difference in the stability results Generally if you do your equilibrium solving using the form SOLVE FSM UPRIGHT things will work out in a reasonable way with the CG elevation being done at zero heel If you want to use FSM rather then CG shifts in a Severe Wind and Rolling
49. acro is executed You might be tempted to ask whether this doesn t violate the rule about sequential processing that we learned early in the course The answer is no commands are always processed in the order in which they are presented to the command processor The Macro command is processed like any other command when it comes up in the sequence It does its thing which is simply to store its body in the program s memory The Macro command doesn t care what is in those lines Later when the command to execute the macro is encountered the lines from the body of the macro are retrieved from memory and fed to the processor one by one in sequence If you remember that everything is done sequentially you will have no trouble getting into macros with parameters macros executing other macros macros defining macros and macro loops and you will begin to utilize the full power of macros to organize and shorten your run files and most importantly to automate your work An important feature that is provided with macros is the ability to modify the commands within the macro at the time the macro is executed There are several ways of doing this using variables and macro redefinitions but the primary method is through macro parameters Here is an example MACRO T TRIM 1 GES 340 5 3 5 v y 9 0 TUNES SEO 39 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com T la The 961 is called a
50. all other weights that may be present If you try this with a nonzero trim as in the example above you will find that the LCG does not exactly equal the LCB Why is that Adding Other Fixed Weights The ADD command is used to add either point loads or distributed fixed weights An example is in the section above on the structure of commands You can change an ADDed weight by repeating the command with the same description Also the weight of an ADDed weight item can be adjusted relative to the declared MAX value with the LOAD command These weight items can be deleted with the DELETE WEIGHT command Finding Equilibrium Suppose you have your light ship and then you change the load configuration Now you want to see how the draft trim and heel have responded and to get some hydrostatic properties Simply issue the SOLVE command without parameters then use any of the commands discussed above under Hydrostatic Properties Load Editor and LEw The LOAD command addresses the loading of tanks or produces a report of tank loads as we saw with the LOAD STATUS command Instead of LOAD tanklist value you can say LOAD tanklist EDIT in which case you bring up a spreadsheet like interactive tool called the Load Editor or LE There are two versions of the Load Editor LE and LEw LEw is the more advanced version and gives you loads of options If LEw is installed on your computer that is what you get with the LOAD EDIT command If not you
51. ary sailing vessel the vessel must be assumed 1 To be under bare poles or 2 Ifthe vessel has no auxiliary propulsion to have storm sales set and trimmed flat d The criterion specified in this section is generally limited in application to flush deck mechanically powered vessels of ordinary proportions and form that carry cargo below the main deck On other types of vessels the Coast Guard Marine Safety Center or the ABS requires calculations in addition to those in paragraph a of this section On a mechanically powered vessel under 328 feet 100 meters in length other than a tugboat or a towboat the requirements of 8170 173 are applied 64 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Severe wind and rolling criterion weather criterion 3 2 1 Assumptions The ability of a ship to withstand the combined effects of beam wind and rolling is to be demonstrated for each standard condition of loading with reference to Fig 1 as follows the ship is subjected to a steady wind pressure acting perpendicular to the ship s centerline which results in a steady wind heeling lever w1 from the resultant angle of equilibrium 00 the ship is assumed to roll owing to wave action to an angle of roll 01 to windward the ship is then subjected to a gust wind pressure which results in a gust wind heeling lever w2 free surface effects as described in 4 are to be accounted for in the
52. asured perpendicular to the base plane of the ship s coordinate system while origin depth is measured on a line that is perpendicular to the waterplane 2 Draft requires additional qualification viz the location along the length of the vessel at which the draft is taken draft at the FP draft at the AP LCF draft etc and 3 Draft can reference some line other than the base line keel draft for example A certain form of the DRAFT command is used to change the draft reference line For example DRAFT Keel 0 04 50f 1 04 50a defines a sloping draft line that is below the base line After this command has been issued all drafts in the reports will be referenced to this Keel draft line and all draft inputs will assume this line as well To revert to baseline drafts the command is simply DRAFT BASELINE When the ship is upright or nearly so draft is often used because it relates to markings on the hull of the actual ship As the inclination becomes greater draft becomes less useful At 90 degrees heel draft is undefined GHS will allow draft to be used only at inclination angles less than 45 degrees Origin depth is always usable regardless of the inclination We will defer the discussion about how to set drafts until we get to setting up specific load conditions 34 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com FP AP and LBP GHS does not derive the locations of
53. ations may be determined in accordance with the filling level in each tank at the stage of the transfer operation 4 7 GM0 and GZ curve corrections 4 7 1 The corrections to the initial metacentric height and to the righting lever curve are to be addressed separately as indicated in 4 7 2 and 4 7 3 4 7 2 In determining the correction to the initial metacentric height the transverse moments of inertia of the tanks are to be calculated at 0 degrees angle of heel according to the categories indicated in 4 3 1 4 7 3 The righting lever curve may be corrected by any of the following methods Correction based on the actual moment of fluid transfer for each angle of heel calculated corrections may be calculated according to the categories indicated in 4 3 1 67 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Correction based on the moment of inertia calculated at 0 degrees angle of heel modified at each angle of heel calculated corrections may be calculated according to the categories indicated in 4 3 1 Correction based on the summation of Mfs values for all tanks taken into consideration as specified in 4 8 1 4 7 4 Whichever method is selected for correcting the righting lever curve only that method is to be presented in the ship s trim and stability booklet However where an alternative method is described for use in manually calculated loading conditions an explanation of the di
54. automatically When you refer to a particular Shape you can always do it through a Component since all Shapes are referenced by at least one Component 18 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com About Units in Section Editor Section Editor allows you to work in any convenient units and even to switch between units The Units command will change the displayed units Use the arrow keys to scroll through the options You can also enter units different from the displayed units by including the appropriate forms of the numbers To see what those forms are simply try different display units and note how the coordinates are shown Entering Offsets with Section Editor Now we re ready to enter points for the first section or shall we call it a station The terms are interchangeable in this context A prompt to enter the longitudinal location of the first station appears automatically This is the Station command which you can give any time you want to add a new station Decide where you want the origin to be then enter the station s location relative to the origin Stations can be entered in any order To delete a station hit Ctr F4 You can always go back and edit a station if necessary After you give the section location start entering its points The Insert command will automatically appear waiting for you to enter the transverse and vertical coordinates of the first point A comma or a space
55. calculation it gets a little more complicated than what was shown in the previous section 59 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com There are some choices to make about when and how to apply the FSM Here is the recommended sequence ROLL IMO FSM MMT OFF OLVE FSM UPRIGHT NGLES MMT WIND M O Hop MT VE FSM UPRIGHT EEL ROLL A LIM FSM LH H o 60 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com An Intact Stability Exercise Find out whether FV GF complies with these intact criteria described more fully on the following pages 46 CFR 170 173 Paragraph B Vessels of Unusual Proportion and Form 46 CFR 170 170 GMWeather Criterion MO Severe Wind and Roll Assume the following Light Ship 156 0 Long Tons at 0 56f 0 10 56 Downflooding points 1 ER VENTS 22 8f 7 0s 15 0 SYM 2 PORT CABIN DOOR 10 0f 9 0p 14 0 TIGHT 3 STBD CABIN DOOR 5 0a 9 0s 14 0 TIGHT Load sequence changes only Fixed loads Tank loads Departure Crew amp effects 2 0 25f 0 25 0 WT1 0 95 Stores 12 0 14f 0 15 0 WT2 0 95 Net on deck 5 0 20a 0 13 0 WT3 0 95 FODAY 0 95 LUBE S 0 95 HYDR P 0 95 FW 0 98 HOLD 0 0 Arrival at fishing grounds Stores 8 0 14f 0 15 0 WT1l 0 05 LUBE S 0 66 HYDR P 0 66 FW 0 66
56. can be used as a delimiter between these two numbers Let the first point be at the centerline on the bottom of the hull So the first number will be zero followed by the height above baseline Assuming you are making a station in the full beam portion of the vessel the offsets would be Point 1 0 0 0 0 Point2 4 0 0 0 Point3 4 0 2 5 Points always proceed in the counterclockwise direction Normally you start at the keel and go around and up to the deck edge Since we are dealing with a centerline Component you can stop at the deck edge The other side is implied What about the top of the section from the deck edge to the centerline It too is implied Since all sections are closed curves by definition there is no such thing as an open top For this simple hull you need only three points per station At the stem you can use small transverse offsets slightly greater than zero for the second and third points If a point is entered incorrectly move to that point using the F5 and F6 keys to bring the cursor to the point Then press F2 to switch from Insert mode to Replace mode then retype or edit the numbers to the correct values Alternatively pressing K puts it in Key Editing Mode where the arrow keys can be used to move the point to the correct location Pressing K again or F2 will return to insert mode Another way to insert and edit points is by means of the right mouse button It will insert after the current point or replace t
57. can do the opposite also More than one command can go on one line when you separate the commands with the vertical bar character P For an example see the next section Light Ship Weight If you know the light ship weight and its center of gravity use the WEIGHT command to enter this information DELETE ALL WEIGHTS WEIGHT weight lcg tcg vcg The reason for the DELETE ALL WEIGHTS is to make sure you do not have any added fixed weights in effect Normally you would give the WEIGHT command before any ADD commands see the next section so the DELETE command here would not be necessary You see the WEIGHT command actually sets the total Fixed Weight including all ADDed weights that might be present It does that by setting the Light Ship weight to the difference 51 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Another way to get a light ship weight is to derive it from a given waterplane Set up the waterplane then solve for the required light ship at that waterplane Here is an example exercise HEEL 0 TRIM la DRAFT 5 5 VCG 6 5 SOLVE WEIGHT LCG TCG STATUS After setting up the waterplane we specified the VCG then solved for the displacement weight LCG and TCG to make the weights equal the buoyancy and the centers be in alignment perpendicular to the waterplane It does that by changing the Light Ship weight preserving
58. d is beyond what most users would have the time or desire to develop There are two classes of wizards Major wizards are complete application programs for specific purposes Other wizards can be integrated with your Run Files Typically they involve library files having the same name as the wizard with the LIB extension that are used by the wizard and are also usable directly in your Run File To get information about using such a library file directly execute the LIBINFO macro For example RUN FLDINTER LIB FI LIBINFO RIG Wizard This is a major wizard essential for MODUs and any other vessels where least stability is not necessarily in the transverse direction or where trim becomes large when heeling transversely The RIG wizard finds the weakest or critical axis and produces composite maximum VCG curves including intact and damage It can import wind heeling moment files to take advantage of wind tunnel tests or it will derive wind heeling moments from the geometry in any direction and as a function of heel This is a flexible and powerful wizard with years of real world experience It produces complete reports and is easy to use Condition Graphics is highly recommended but not essential DAMSTAB2 Wizard The new probabilistic damage regulations are so complex that this major wizard is virtually essential It greatly simplifies the task of defining subdivisions and takes over every aspect of setting up and producing damage stabi
59. dd delete or move sections and points Filling between sections by interpolation is also possible 16 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Deck edge definitions used for deck immersion criteria and margin line assignments can be added and edited SE can also be used to create hull Parts from a table of offsets or by digitizing body plans using digitizing tablets For viewing the geometry without an editing capability it can be used in DISPLAY mode DISPLAY commana Starting Section Editor If a Geometry File is in main memory the same file is automatically read by SE when started If no geometry file was in memory you can use the Read command while in SE In order to become familiar with Section Editor do the following 1 With the command prompt is showing in the GHS main program first make sure there is no Geometry File currently in memory use the CLEAR command if necessary 2 Type READ FV GF which will read the fishing vessel model that comes with GHS 3 Give the command SE to bring up Section Editor Now you should be looking at the Section Editor s main screen showing profile and plan views of this simple fishing vessel model Here are some things to explore Use the Tab Shift Tab and Enter to display different views of the geometry Tab will cycle through the profile plan isonometric body views The Enter key toggles between the profile plan mode and the
60. e LIM parameter RA LIM There are two ways to specify the range of angles that the RA command will use One way is to list the angles on the command itself RA 0 55 2562 0 A better way is to manipulate the ANGLES list This list is held in the program s memory and is what the RA process uses when you do not give angles with the command Initially this list is 0 5 60 Changing it involves the ANGLES command For example ANGLES 0 2 10 15 90 establishes the angles at 2 degree increments up to 10 degrees then 5 degree increments to 90 degrees If you want the heel angles to progress to port instead of to the starboard side use negative angles If you want the direction to go in whichever direction the vessel is heeling initially the commands would be SOLVE ANGLES This looks at the present heel angle and reverses the direction of the existing angles list if necessary in order to make it go in that same direction It is important to know that RA normally starts the curve at the present heel angle In other words the angles whether given directly with the command or through the ANGLES list are relative to the heel angle at the time the RA command is issued This is useful if you want to start the curve at equilibrium SOLVE ANGLES RA But if you want to start at zero heel use a HEEL command before RA SOLVE ANGLES HEEL 0 RA Normally the RA process perfor
61. e of calculating the criteria of 3 2 2 the angles in Fig 1 are defined as follows 00 Angle of heel in degrees under action of steady wind 01 Angle of roll in degrees to windward due to wave action calculated as follows 0 109kX X rs 02 Angle of downflooding 0f in degrees or 50 or Oc whichever is less Of Angle of heel in degrees at which openings in the hull superstructures or deckhouses which cannot be closed weathertight immerse In applying this criterion small openings through which progressive flooding cannot take place need not be considered as open 0c Angle in degrees of second intercept between wind heeling lever w2 and GZ curves OR 00 01 X1 Coefficient defined in Tab 1 X2 Coefficient defined in Tab 2 k Coefficient equal to k 1 0 for a round bilged ship having no bilge or bar keels k 0 7 for a ship having sharp bilge For a ship having no bilge keels a bar keel or both k is defined in Tab 3 r 0 73 0 6 OG T1 OG Distance in m between the center of gravity and the waterline positive if center of gravity is above the waterline negative if it is below T1 Mean moulded draught in m of the ship s Factor defined in Tab 4 Note 1 The angle of roll 01 for ships with anti rolling devices is to be determined without taking into account the operations of these devices Note 2 The angle of roll 01 may be obtained in lieu of the above formula from model tests or full scale
62. e that use intermediate tables for the sake of efficiency Because GHS has a highly efficient calculating engine it performs the essential volume integrations very quickly and so is able to provide both speed and the accuracy inherent in using the first principles approach The Purpose of this Document This document serves as text for the standard 3 day introductory GHS training course It assumes no initial familiarity with GHS It does assume familiarity with personal computers under the Windows operating system The important concepts and principles upon which GHS is built are presented in some detail but in other respects this is not a complete user s guide to the program The GHS User s Manual is the complete reference document Most of the User s Manual is conveniently accessible through the Help menu in the GHS program Topics are presented in a particular order that builds on material presented previously Sometimes the explanation of a program feature is split to provide necessary prerequisite information only where it is needed while avoiding information overload before it is needed Therefore this should be read in its natural order not at random By the time you finish going through this document you will know how to get useful work done with GHS and you will be oriented well enough to make good use of the User s Manual to extend your knowledge No attempt is being made here to cover every detail of GHS The emphasis is on simp
63. e waterplane This is used primarily for longitudinal strength calculations but the wave profile will be recognized in all other calculations as long as it is there The WAVE command is used to establish the wave The three primary wave parameters are Phase Length and Amplitude By default the Length is the same as the LBP and the Amplitude is 1 20 of the length But the Phase must always be specified If you think of a periodic wave being based on angles running from 0 to 360 degrees Phase is the angle of the crest relative to the origin Suppose the origin is at the mid section and the wave length is LBP Then when the peak of the wave is midship the Phase is zero WAVE 0 and when peaks are at the end perpendiculars the phase is 180 degrees WAVE 180 If the LBP is not defined or you want some other wave length a second parameter must be 36 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com included giving the Length to be used Pull down the Help menu and look at the WAVE command document to see all of its available parameters To turn off a wave and revert to the flat waterplane the command is WAVE OFF Curves of Hydrostatic Properties Here we deal with the properties of the entire vessel at a series of waterplane levels All Parts that are subject to the waterplane are included even flooded tanks and any Wave that may have been specified is taken into account There are two sorts of hydrostat
64. eed cross curves they are available there should be little need for them in the modern world The command is CC and like the GHS command the independent parameter is either displacement or draft For example CC 2 0 2 5 8 0 MARK DECK computes the righting arms for the range of drafts specified and includes a line at deck immersion Another example CC DISPL 50 100 300 MARK FLOOD 38 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com computes the righting arms for the given range of displacements including a line at downflooding Cross curves can be run with fixed or variable trim and with the assumed VCG at any value If you want to fix the trim the command is FIX TRIM and to restore free trim the command is VARY TRIM Macros A macro is simply one or more commands that have been stored under a certain name so they can be conveniently executed by giving that name It is easy to define a new macro For example MACRO ST STATUS WEIGHT DISPLACEMENT FREEBD Now we can execute that rather lengthy STATUS command simply by saying EXECUTE ST or even more simply by POI where the dot is the short way of saying EXECUTE Note that the MACRO command is a multi line command where all of the lines between the word MACRO and the final slash are stored under the name that appears on the first line No processing of these lines takes place until the m
65. erion it is dealing with However there remains in the program s memory a record of the composite maximum VCG data This is the data that the WRITE command put out MAXVCG LOOKUP After the MAXVCG command completes the information that appeared in the tabular report is held in the main program s memory as we have said One way to utilize this information is to use the MAXVCG command in LOOKUP mode In this mode it does not actually compute or generate any new max VCG information It merely goes to the information stored in its memory If the MAXVCG command issued in LOOKUP mode has all the same parameters as the one that originally generated the information its job is easy since it will be simply retrieving information at the same points But if different drafts or displacements appear in the LOOKUP mode it will be doing interpolations within the stored data A MAXVCG LOOKUP Exercise Perhaps you really wanted your composite maximum VCG curves to be at constant trim not constant LCG This can be done in LOOKUP mode since the MAXVCG LOOKUP command parameters do not have to match those used originally For this exercise write a new run file that picks up your MAXVCG DAT file and produces a separate report of the composite curves where each curve is at a certain trim value Of course if the parameters you supply with this MAXVCG command cause it to look outside of the data previously computed it will return not
66. est is similar to what we did to make the hull Give it some slight transverse offset not simply zero For example Point 1 0 0 4 0 Point 2 0 01 4 0 Point 3 0 01 15 0 For the last aft most point out at the clew still use three points and make the third point slightly higher than the second rather than having two points at the same location Two stations are sufficient but you will still have to Fill If you want to make the mast as an additional Component create the second Component again with the Name command Name rigNmast c Tab to the Body view if you are not there already and go ahead with the first station on the mast Note that the SAIL C component is still showing since it is within the same Part If you want to have only one Component showing press Ctr P Two stations will suffice for the mast and no filling is necessary since the spacing is already close enough Supposing you accidentally made the mast Component such that it overlaps the sail Component and you want to move the sail aft a bit You may remember the mention of Component Vectors previously and you will have noticed that the Section Editor screen shows the Vector of the current Component You can change this vector through the Edit command First make sure you are looking at the Component whose vector you want to change using the Up Down arrow keys if necessary In this case while highlighting the RIG SAIL C enter the command Edit vector 0 5 0 0 This
67. ews the calculation of a righting arm as a process that must include a correction in order to produce a realistic result But this is not true GHS has always starting with version 1 00 produced realistic righting arms without applying any corrections The term moment of transfer implies an alternative to free surface moment Technically GHS does not use moment of transfer though the results are the same if the moment of transfer is done rigorously and in all directions not simply transversely A different subject is GM The calculation of GM from the waterplanes does not involve any CG shifts and it is incorrect to talk about moment of transference in that context More about GM later If that were the end of this subject FSM would not seem too difficult to apply But there is more and it is like opening the proverbial can of worms Things get messy when you try to force artificial methods on reality But that s what the regulations do in many cases The first issue is how the FSM is derived Is it to be taken as 1 true FSM at the equilibrium angle 2 true FSM from zero heel and equilibrium trim 3 true FSM from zero heel and zero trim 4 true FSM only for tanks that are not nearly full and zero or some other value for the others 5 maximum FSM at some heel and trim for some or all tanks 6 maximum FSM regardless of the current load or zero for empty or pressed tanks 7 some reduced FSM value when the load is bel
68. fferences which may be found in the results as well as an example correction for each alternative are to be included 4 10 Remainder of liquid 4 10 1 The usual remainder of liquids in the empty tanks need not be taken into account in calculating the corrections providing the total of such residual liquids does not constitute a significant free surface effect 68 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Longitudinal Strength Prerequisite to any Longitudinal Strength calculation is establishing a longitudinal weight distribution for light ship and any other fixed weights aboard that extend over a significant length Weights from tank loads are distributed automatically Both the WEIGHT and the ADD commands will take multiple weight density curves in lieu of point weights Getting a light ship distributed weight curve to exactly match the known total light ship weight and LCG is made easier by a feature where GHS scales its magnitudes and shifts its locations to match the known values For example WEIGHT 6 0 Q097 57 f 14 0 885 05f 19 6 885 04f 22 8 5 03f 20 0 5 03f 21 2 2 90a 5 5 12 0f 3 3 0 0 WEIGHT 2981 257 48 419f 0 000 6 503 The first WEIGHT command establishes the light ship weight distribution giving weights in tons meter at several locations Note that there are actually two curves the second being separated from the first by a semicolon The progra
69. for onboard use Advance Features AF probabilistic damage and oil outflow also submarine stability GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Crane CR vessel mounting crane calculations including Crane Operator Output Tables Enhanced by LEw and CG modules Grain Shift GS volumetric heeling moments of bulk cargo in general holds e Multi Body MB interactions between two or more floating bodies Hull Maker HM barge shaped GF file generation based on input parameters such as principal dimensions sheer rake deadrise bilge radius etc Being an optional module does not necessarily mean that additional software files are involved though in some cases it does In all cases access to these modules is through the GHS main program Installation and Setup The organization of shortcuts data files and folders on your computer and or network is a matter of personal preference and company policy so it will not be addressed here However in any installation all GHS program files must reside in a single directory folder For the purpose of this training it is recommended you make a new folder in which to install your training version of GHS keeping it separate from your permanent GHS program folder GHS uses various devices for copy protection The most common is a USB dongle When doing a new installation do not insert the dongle unti
70. g Book Standard Course Rev 07 15 Creative Systems Inc www ghsport com NFOCSLE C FOCSLE DXF 3D XYZ NOWAIT EXPORT HUL CLEAR IMPORT HULL DXF HULL HULL C FV1 GF 3D XYZ NOFILL IMPORT FOCS FIXUP FV1 GF HULL HULL C DE FIXUP FV1 GF HULL FOCSLE C D DISPLAY Deck Edge Cons E DXF HULL FOCS E C FV1 GF 3D XYZ NOFILL CKEDGE iderations NOFILL ECKEDGE NOFILL If you bring up DISPLAY or SE and you have marked the deck edge on both HULL C and FOCSLE C you will notice brown lines in the iso view showing where Model Converter put the deck edge Now here is a problem Does this represent reality In this case the answer would be no since the FOCSLE C Component is a watertight structure that covers the main deck forward We would like to remove the deck edge marks from HULL C where it is covered by FOCSLE C It is not difficult to do this using Section Editor If you move the point marker to the point at the deck edge you will see DK following the point s coordinates Simply deleting the DK removes the deck edge mark on that station You could do this for all of the stations on HULL C that are in way of FOCSLE C But you can also do it with the FIXUP command By adding a range of locations to the DECKEDGE parameter we can specify the length over which the deck edge is to be marked
71. gth curves at various values of assumed permeabilities A list of tentative bulkhead locations can be given on the same command line by means of the BHD parameter Here is an example where the NC parameter specifies how many adjacent compartments are to be included when the tepees are drawn ROJECT FL1 EAD TANKER GF EPORT RAFT 5 6 E WEIGHT LCG 0 7 0 8 0 9 BHD 85 70 60 40 25 10 0 NC 2 RT PREVIEW PORT OFF O lt A B E FJ Fg O E OL ce Ce am Q gt wt iw 71 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Report Options The following Run File illustrates some of the options available for reports project reports read fv gf draft 5 veg 7 solve weight lcg add crew amp effects 0 5 25 0 25 add stores 1 14 0 15 add net on deck 2 20 0 13 load wt fo lu fw 0 95 print configure nofoot print configure font courier foot footfoot txt logo minilogo bmp report nofoot report nographs report box classic report box bw report box color report p 0 report p 45 solve status page ra report preview thick 4 count report off As you know by now REPORT filename opens an output file for the reports using the specified file name If no name is given the project name is used with the PF extension The REPORT command also has other modes and options in which it can
72. h wetted surface area included 47 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Free Surface and Free Surface Moments A misconception we encounter frequently is that free surface is described by its free surface moment FSM This is only partially true Free surface is the surfaces of liquids in tanks which causes the centers of gravity in such tanks to shift depending on the heel and trim of the ship FSM indicates how much the center of gravity will shift with a small change of heel or trim at a particular heel and trim FSM is like GM it gives you the initial slope but does not tell you anything about what happens at greater angles GHS always takes free surface into account unless you deliberately shut it off by explicitly freezing tank contents in which case you no longer have free surface Normally it does so by constantly recalculating the locations of the CGs in the tanks whenever the ship s heel or trim changes As mentioned before this is sometimes called the moments of transference method We call it simply CG shifts and that is why we consider tank weights to be variable and non liquid weights to be Fixed The phrase free surface correction often appears in stability regulations Even when actual CG shifts are allowed it is described as a correction based on the actual moment of transfer This language implies that there is something deficient that needs to be corrected It vi
73. have in the rakes of a barge The reason for this has to do with the waterplane properties that depend on the plane that is obtained by cutting through the stations At the ends of this plane there can be a severe lack of definition particularly when its ends fall between stations If the station bottoms are V shaped the waterplane endings will be fine and this problem is usually 37 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com insignificant But where the stations are broad on their bottoms the waterplane endings will also be wide and blunt and their exact shapes will be difficult to get by cutting through the existing stations GHS makes an attempt to extrapolate properties for such poorly defined waterplane endings but the results are not as accurate as they would be from closer station spacings If you get your curves of hydrostatic properties at closely spaced drafts this effect will be more apparent and it may take a large number of additional stations at the ends of the hull to yield smooth curves The displacement related curves are not affected by this to any significant degree It is only the waterplane related curves such as KM Weight to Immerse and Moment to Trim that are subject to this problem These extra stations that might be added in order to smooth the curves of hydrostatic properties will have no significant effect on the displacement or the stability calculations With the possib
74. he FSM assignments before setting the load condition When the Content of a tank is changed from one substance to another and where the densities are different the FSM also changes in proportion even if it is a fixed assigned value About GM The traditional way to calculate GM is from the waterplane moment of inertia which together with displaced volume yields BM and applying that to the CB we get the metacenter location and hence can arrive an GM All this depends on the vessel being at equilibrium otherwise we have to assume a CG location that would put it in equilibrium When slack liquid loads are present in tanks the metacenter is affected which affects the GM However the traditional approach to this is to leave the metacenter alone and correct the VCG using the FSM Obviously this is technically incorrect since the CG does not change as a result of the free surface You could freeze the tanks and have the same CG yet the GM would increase Therefore GHS always puts the free surface effect in the BM where it belongs rather than leaving it out of the BM and making a VCG correction Either way yields the same GM but the BM from GHS will not agree with the BM from a method that corrects the VCG GM can also be calculated from the the RA curve since GM equals the slope of the RA curve GHS gives you this option and it has the advantage of being less sensitive to waterplane discontinuities This GM option appears as optional
75. he RUN EXECUTIVE WIZ command appears in the start up file If both GHS SAV and GHS LF exist GHS SAV runs before GHS LF Direct Command Entry Exit the Executive Wizard dialog if it is present and you will see somewhere on the screen a blinking cursor This is the command prompt for typing a command directly For example you could type RUN EXECUTIVE WIZ to restore the Executive dialog In most cases the command name can be abbreviated The minimum abbreviation is indicated in the User s Manual by underlining A quicker way to find out the minimum abbreviation is in the Help menu where it is capitalized The Structure of Commands Commands follow certain formatting rules All commands start with the command name which as mentioned earlier usually can be abbreviated GHS Training Book Standard Course Rev 07 15 Creative Systems Inc www ghsport com After the command name there are usually parameters that help to define what you want to happen when the command is executed by the program Separators can be spaces or commas In many cases you can also separate the command name from the first parameter with an equals sign and sometimes that looks better Each command has its own syntax which is shown in detail in the User s Manual But there are certain syntax conventions that are followed throughout the program More will be presented on this later For now it is sufficient to understand that
76. he current point with coordinates derived from the present mouse pointer The left mouse button can be used to select points 19 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Since the Insert mode will always have your new point inserted after the current point how do we insert a point before the first point Go to the first point then while in Insert mode press F5 and it will say pre insert which means the point you now enter will be inserted before the first point now becoming the first point To delete the current point hit F4 Saving Your Work Writing the Geometry File Writing your work to a Geometry File is done using the Write command For example Write EX1 GF will write your current model to a Geometry File named EX1 GF You can also scroll through the GF files in the working directory using the arrow keys If an existing file is selected it is overwritten without warning It is easy and prudent to save your work often using the Write command The Arc Command Shall we add a bilge radius The Arc command makes it easy On any station go to the point at the intersection of the bottom and side then give the command Arc radius 1 0 and the original point becomes an arc How Many Stations There is no need to enter more than three stations in this simple exercise one at each end and one at the knuckle will be sufficient GHS requires station spacing no greater than 1 20 of the
77. he righting arm curve are addressed viz area area ratios minimum angles etc The Limit command does not reference any particular stability criterion rather you write Limit commands using parameters that in your judgment represent the requirements of a given criterion Several of these limits can be in effect simultaneously thereby addressing each aspect of the criterion However it is usually not possible to represent more than one stability criterion simultaneously with the same set of Limit commands For example you would treat ordinary energy stability separately from weather stability You will want to become very familiar with the Limit command in all or most of its forms The User s Manual is the best source for this information which is also available through the Help LIMIT At the end of the Limit documentation you will find some examples Limit commands will be covered in more detail when we get to righting arm curves and specific conditions For our immediate purposes here are two sets of Limit commands representing two different stability criteria UNITS LT LIMIT 1 AREA FROM 0 TO 30 gt 10 3 IMIT 2 AREA FROM 0 TO 40 OR FLD gt 16 9 LIMIT 3 AREA FROM 30 TO 40 OR FLD gt 5 6 LIMIT 1 GM UPRIGHT 0 49 LIMIT 2 RA AT 30 OR MAX 0 66 LIMIT 3 ANGLE AT MAX 25 Critical Points GHS gives you the ability to mark any point on the vessel inside or out with points that are of interest with res
78. hing and the curve will be incomplete Your run file should look something like this EAD FV GF EPORT GAA N U NITS MT MAXVCG DIS REPORT PR REPORT OFF ROJ MAXGCG3 PL EVI 50 EW UN MAXVCG DAT CALL 100 250 TRIM 45 0 Sf 0 25 1 LOOKUP GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Specific Conditions Setting Up a Waterplane Earlier we discussed the HEEL and TRIM commands which provide for the waterplane s attitude or inclination The third waterplane parameter is the origin depth which was also introduced at that time You can set the origin depth directly using the DEPTH command for example DEPTH 5 0 changes the origin depth without affecting the trim and heel angles If you define a waterplane in this manner be sure that your TRIM command comes before the DEPTH command Here s why When you change the trim by any significant amount the position but not the trim or heel of the waterplane becomes undefined GHS deliberately makes the origin depth undefined as a result of changing the trim Changing the trim alone would rotate the waterplane keeping the origin depth constant which is what happens when you change the heel angle If the origin happened to be located near midship this might be an acceptable result since the draft at one end would increase while the draft at the other end would decrease But if the origin were
79. hs Use P 0 005 for the purpose of 170 170 Do not include Reference Point data in output Questions 1 Do the results indicate the vessel meets all three criteria 2 Do you suspect any error with input information 62 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com 170 173 Criterion for vessels of unusual proportion and form a If required by the Coast Guard Marine Safety Center or the ABS each mechanically powered vessel less than 328 feet 100 meters LLL other than a tugboat or towboat must be shown by design calculations to comply with 1 Paragraph b or c of this section if the maximum righting arm occurs at an angle of heel less than or equal to 30 degrees or 2 Paragraph b of this section if the maximum righting arm occurs at an angle of heel greater than 30 degrees b Each vessel must have 1 An initial metacentric height GM of at least 0 49 feet 0 15 meters 2 A righting arm GZ of at least 0 66 feet 0 20 meters at an angle of heel equal to or greater than 30 degrees 3 A maximum righting arm that occurs at an angle of heel not less than 25 degrees 4 An area under each righting arm curve of at least 10 3 foot degrees 3 15 meter degrees up to an angle of heel of 30 degrees 5 An area under each righting arm curve of at least 16 9 foot degrees 5 15 meter degrees up to an angle of heel of 40 degrees or the downflooding angle whicheve
80. ic properties One is pure hydrostatic properties that have nothing to do with the center of gravity These are available through the HS command where origin depth is the independent variable For example HS 2 2 1 8 Hydrostatics from 2 to 8 feet 0 1 increments The other sort of hydrostatic properties recognizes the effect of the CG and therefore is able to include moments to trim The command for this is GHS and the independent parameter is displacement weight or draft In the GHS command draft is assumed to be at the the LCF by default but any other draft location can be specified For example GHS DRAFT 80 22 2 1 8 while GHS 2 2 eni o8 will assume the drafts are to be at the LCF If there is no trim it makes no difference where the drafts are taken If there is trim the location of the LCF generally depends on the draft which means that the program must do some extra work to set the LCF draft to a given value but it does so very quickly An Exercise in Curves of Hydrostatic Properties Write a run file to compute curves of hydrostatic properties including graphs using the FV GF model CLEAR READ FV GF REPORT HSTATICS PF REPORT PREVIEW More About Station Spacing In order to get nice smooth curves of hydrostatic properties you may have to add more stations to your hull geometry model near the ends especially when there is little or no deadrise in the station curves such as you would
81. ight above the waterplane is available from the WIND REPORT command Severe Wind and Rolling Calculations When wind and waves are on the beam the ship will need to have enough righting energy available to absorb the kinetic energy during a rebound from a severe roll upwind of its steady wind induced heel GHS provides a mechanism for conveniently arriving at the windward heel angle so that these energies can be compared in the righting arm curve With a heeling moment in effect the equilibrium heel angle can be found simply by issuing the SOLVE command without parameters Now if the magnitude of the initial roll is known the upwind heel angle can be set simply by giving the command HEEL r Where r is the roll angle A more convenient way of specifying the roll angle is provided by the ROLL command For example ROLL 20 HEEL ROLL does essentially the same thing except that it conveniently moves the heel angle in the direction opposite to the initial heel angle Further if the value of the Roll is not fixed but is to be calculated from the present condition according to the IMO rolling formula then the ROLL command can be given once in the form ROLL IMO and the actual roll value will be recalculated at the time it is used 57 GHS Training Book Standard Course Rev 07 15 Creative Systems Inc www ghsport com A typical sequence of commands to check the energy available to resist a
82. imply ED and the text editor will come up ready to create or edit the Run File named accordingly For example PROJ DAY1 ED Now you are ready to edit the file DAY1 RF in the current working folder The Project Folder System If you pull down the Project menu you will see that there is a complete facility for managing project folders and sub folders If you do not already have an established structure for your projects you might want to consider using this system It is optional and is explained in the manual under the PROJECT command For lack of time it will not be covered in this course The Phases of a Project The chart below depicts the steps involved in producing a report how the various divisions in the software relate to these steps and which files are involved It is worth studying this chart It will help you keep your bearings as you navigate through the process from starting to build geometry to producing the final report Note the two main phases 1 Model Building and 2 Analysis using the model Model Building here refers to the process of creating the Geometry File In one sense as noted earlier this is not the complete model since light ship weight and other non liquid weights are also essential to the overall model But we do not include them in the Model Building phase since they are provided in the Run File during the Analysis phase Inputs Keyboard 9 ni
83. ir familiarity with spreadsheets The spreadsheet appears to process its inputs simultaneously the position of an item on the page does not necessarily imply a sequence If not warned about this in advance they will look at a GHS Run File as a if they were looking at a spreadsheet They will not realize that command A must precede command B if the program is to have the benefit of command A when it processes command B GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com A Run File is simply the text file where you write your commands The preferred file name extension for Run Files is RF and they can be created and edited using the text editor that is available within the GHS program You could type your commands directly into the program but using a Run File saves you from having to repeatedly enter commands When you tell GHS to run your Run File it simply processes the commands from the file sequentially line by line Your Run File in combination with the Geometry File will produce a Report File The report could be something simple like the results of an inclining experiment or it could be an entire Trim and Stability book You could say that the purpose of this training course is to teach you how to write Run Files Almost everything including model building can be done through Run Files The GHS Command Language There are certain special commands that can be used to make your Run File into
84. ith Limits in effect there is a choice as to how the Limit evaluations are to be shown Normally the margins are shown as they are in the MAXVCG report The LIM ATTAINED parameter will cause the attained values to be shown When the special case area limit that requires two sequential limits is present see Help LIMITS the LIM ATTAINED COMBINE parameter will result in the best presentation There are many additional features of the RA command all of which are well documented in Help RAH Heeling Moments GHS provides for heeling moments with the HMMT command You can give a fixed value or function or have the heeling moment be derived from wind pressure turning or tank CG shifts A heeling moment report is available from the HMMT REPORT command It includes all of the sources that go to make up the current heeling moment Wind Heeling In order to get heeling moments from wind pressure the WIND command must precede the HMMT command Wind pressure can be given as a constant as a profile depending on height above the water or as a speed in knots referenced to 10 meters above the water with a standard profile implied In order to produce an adequate heeling moment from wind pressure the geometric model must include all elements of the superstructure and rig that are significant contributors to the wind heeling moment Two methods of extracting effective lateral plane areas for wind heeling are available 1 the traditional lateral p
85. l prompted to do so Among the files that come with GHS you will find one named INSTALL TXT lt contains complete step by step instructions for all types of installations On a stand alone computer a new GHS installation or an update goes like this 1 Insert the GHS installation CD or other medium into your computer 2 If Welcome to GHS does not appear run INSTALL EXE from the CD 3 Click through the installation procedure following any special instructions that might appear 4 If your computer is installing a USB dongle for the first time insert the dongle into a USB port and confirm any security dialogs that might appear if New Hardware Wizard starts up select the automatic option If you inserted the dongle before installing GHS see Troubleshooting in INSTALL TXT Starting Up the Program GHS can be started using a Windows shortcut A shortcut created on the desktop will default to a working folder where the GHS main program file GHS EX E is located However this should never be used as the working folder Therefore be sure to change the Start in folder to a working folder where you want to keep your data files for a particular project The working folder must never be the GHS program folder nor should it be a sub folder within the windows program files directory GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com
86. lane projection where the area is the summation of the lateral projection of all above water components of all hull and sail class Parts 2 the Band 56 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com method where areas are accumulated in horizontal bands starting at the waterplane and going up to the highest element of the model The lateral plane method ignores lateral overlaps of Components Therefore it tends to yield unrealistically large lateral areas if the calculation is done at other than zero heel However a wind heeling moment based on the lateral plane at zero heel is an accepted method and is prescribed in some regulations The Band method is able to recognize overlaps in the lateral projections and produce heeling moments that are more realistic at any heel angle However it requires much more calculating time and will significantly slow the righting arm calculations when it is in effect The command HMMT WIND causes the heeling moment to be based on the specified wind pressure and lateral area By default you get the lateral plane method The optional parameter for the Band method is BAND w where w if present specifies the width of the bands which of course are more like heights The smaller the w value the slower the calculations will be and if too small it will run very slowly with no significant improvement in accuracy A table and plot of wind pressure or speed as a function of he
87. le exception of GM stability information does not depend on waterplane calculations When free surface moments are used GHS does not normally use FSM in its treatment of free surface as will be explained later the tank waterplanes are also significant Generally if the hull is producing smooth curves of waterplane properties the tank FSMs will also be sufficiently accurate if the tanks have been FIT to the hull during their creation in Part Maker Either Model Converter or Section Editor can be used to conveniently insert additional stations into a hull model by interpolation In most cases the interpolation yields acceptable results But you should always inspect the new stations in Section Editor and make any necessary corrections Since extra stations require extra calculation time it is not productive to have more stations than necessary Closely spaced stations in the mid body contribute little to accuracy but may add significantly to the run time Choosing your Drafts Another irregularity in the plots of the curves of hydrostatic properties occurs when there is an abrupt change in the waterplane at some draft Since the curves are plotted using non linear interpolation this can result in overshooting at the draft where an abrupt change occurs It may be necessary to select closely spaced drafts on both sides of the transition in order to force the curves to change their direction abruptly Cross Curves of Stability In case you n
88. licity It is left to the user to build on this foundation as needed with the User s Manual as the main source of information possibly augmented with advice from the GHS technical support team or the online help www GHSport com support contains all the latest Training Guides Tutorials amp Wizards Bulletins Questions amp Answers Did You Know articles and sample Run Files GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com First the Geometry File GHS uses a convenient and compact geometry model of the ship that includes all of its internal tank and compartment arrangements and all of its superstructure windage elements This model is contained in a single computer file we call the Geometry File typically using the file name extension GF Since all calculations are based on geometry the first stage of any project is building the geometric model and the first sessions of this training course will teach you how to create Geometry Files The Rest of the Model Fixed Weights vs Tank Loads The Geometry File with its tank models provides for weights and centers of liquid loads but it does not provide weights of structure and other non liquid loads Consider that all of the buoyancy and weight forces derived from the geometry are variable subject to change when the vessel changes its draft heel and trim On the other side of the equation you have the fixed forces from the weight
89. light ship distribution as necessary 69 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com The example above is very simple with only two curves In real life distributed weight curves are usually much more detailed often involving several curves and many more points If you need to go beyond bending moments and get stress and or deflection you will need to provide section modulus and or section moments of inertia as well For this you would use the SMOD command Single values or curves can be specified Section moments of inertia can be given as well either in place of section modulus SMOD Z or in a ratio SMOD Z c where section modulus is given as the moment of inertia divided by the distance from neutral axis Section moduli for both keel and deck stress can be given See HELP SMOD for details If deflection is being calculated and there is no wave present the resulting waterplane with deflection remains after the LS calculation is complete However any change you make in the waterplane after that will remove the deflection You can provide shear and bending moment limits by means of the LSLIM command The limits themselves and also how the results compare to the limits will be shown in the reports If a wave profile is to be included in the LS calculation issue the WAVE command also Remember that a Condition Graphic at this point after a SOLVE will help to verify that the wave has been set u
90. lity It applies to cargo and passenger ships It required the Advanced Features module Condition Graphics and Load Editor are highly recommended GLM MAKER All GLM configurations are done by means of this wizard It offers every option that has ever appeared in any GLM and makes configuring and testing GHS Load Monitor Systems easy Condition Graphics and Load Editor with windows LEw are required If longitudinal strength is involved the LS module is also required If a GLM utilizes Multi Body operations the MB module is required If it involves complex cranes the Crane module is required CRANE Wizard Complex crane modeling including capacity tables and extensive graphics are managed with this wizard Load Editor with windows and the Crane module are required 77 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com FLDINTER Library and Wizard This library provides the essential macro for intermediate stages of flooding including blending densities of cargo and sea water Unlike the major wizards above it is designed to be embedded in the User s Run file No optional modules are required C170170 and C171050 Libraries and Wizards These libraries address GM criteria that are not well suited to the usual criteria represented by Limit commands They provide for the evaluation of load conditions and will also produce maximum VCG curves They can be utilized through their wizards or by usi
91. lues from 5 0f to 1 0a Use the first set of Limit commands shown above Your run file would look something like the Focsle door 23f 8 0 14 0 EA FROM 0 TO 30 10 3 following PROJ MAXVCG1 READ FV GF REPORT CRTPT 2 UNITS LT LIMIT 1 AR IMIT 2 AR EA FROM 0 TO 40 OR FLD gt 16 9 43 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com LIMIT 3 AREA FROM 30 TO 40 OR FLD 5 6 MAXVCG DISPL 50 100 250 LCG 5 0f 4 0f 1 0a REPORT PREVIEW REPORT OFF The Focsle door critical point was added as another flood point in order to demonstrate the effect of earlier flooding This will become significant when we do composite max VCG curves in the next exercise Composite Maximum VCG Curves Often you will need to produce a set of max VCG curves that reflects the results of more than one stability criterion In other words you want the maximum VCG at any point to be the lowest of the maximum VCGs found under two or more criteria or for several damage cases The way this is accomplished is to repeat both the set of Limits and the MAXVCG command for each criterion If you are finding the composite max VCG curve for a series of damage scenarios you would not need to change the Limits but you would be changing the flooding zone There is one more thing The second MAXVCG command and all those that follow it if there are more than two must include the C
92. m automatically combines the two curves Each curve is a series of weight density numbers their corresponding locations Note that the curve goes from point to point It is not a series of weight blocks Itis a series of weight density points If you need to input an existing weight curve that is in the form of blocks you will have to use two points for each block where the density values are the block weights divided by the block lengths The locations in the example above are shown going from forward to aft It is not necessary that the points be given in that order since the program sorts them into order of ascending locations fwd to aft Discontinuities are best represented by two weight densities at nearly the same location If two points on the same curve are at the same location it is important that the one belonging to the forward segment come before the one belonging to the aft segment A good practice is to always give the point locations in ascending order The second WEIGHT command also sets the light ship weight and CG but it does not discard the distribution that has already been defined rather it scales and shifts it as necessary so that it has the required total weight and LCG The same thing can be done with SOLVE WEIGHT For example if you have drafts in a known load condition you can set up that condition enter the light ship weight curve then give the command SOLVE WEIGHT LCG and it will scale and shift the existing
93. most cases is enclosed in parentheses If a Current Parts list exists the parenthetical list can be omitted and the Current Parts list will be used instead If neither exists the command will issue an error message An exception to this rule is the COMPONENT command where it goes ahead with all Parts in the model but the COMPONENT command is exceptional in several ways as we shall see To set a Current Parts list of tanks the command is TANKS list the trailing asterisk can be used on the tank names in list To set the list to all tanks the command would be TANKS To turn off the Current parts list i e to make it empty the command is TANKS OFF Similarly the PARTS command can be used One difference is that TANKS will only accept the names of tank Parts Another difference is that PARTS is smart when you give it the name HULL and there is no Part by that name Instead of issuing an error it defers instead to the first hull class Part in the model This is useful when you want to know the height above water of a certain part as was demonstrated in the previous section Heel Angles and Trim Angles The Heel angle is best visualized looking at a body plan keeping the body plan upright and rotating the waterplane Where the waterplane cuts a section in the body plan you have a line and the angle that line makes with the base line is the Heel angle The sense is positive or starboard if the Heel angle is at a positive rota
94. ms CG shifts in slack tanks which is the most realistic way to represent the free surface effect If you need to have it apply Free Surface Moments instead there are some FSM options FSM causes it to use the formal FSM i e whatever FSM methods have been assigned to the tanks TRUEFSM forces it to calculate true FSM for each tank regardless of the method assignments 55 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com EXTRAFSM allows the shifting of tank contents and in addition elevates the center of gravity such that the initial GM is the same as would result from using the formal FSM When FSM is being applied the report header preceding the RA table shows the FSM application showing exactly how the CG was changed In the CG shift mode this is not necessary and only the Fixed weight CG is shown in the header since the total CG is variable If GM is involved in the Limits the waterplane derived GM will be used unless a GM parameter appears There are several possibilities here for which Help RA is the best reference Several options are available for the graphs The default option is to get the full set of graphs plotting righting arms or moments area or energy and flood point heights Normally the graphs include score lines at significant angles These can be turned off with GRAPH CLEAN which is appropriate if the Limits are not of the sort that address those angles W
95. n IMO roll would be ROLL IMO NITS MT I IND PRESSURE 0 05 OLVE EEL ROLL RA AREA U W HMMT WIND CONST S H 14 in current units wt length 2 If an increase in the heeling moment due to a gust of wind occurs at the rolled angle it can be modeled by using a GUST parameter on the HMMT command The issuance of the HEEL ROLL command then automatically causes the heeling moment to be multiplied by the gust factor from then on until another HMMT command is issued For example SOLVE HEEL ROLL RA AREA HMMT WIND CONST GUST 1 5 lt The gust factor takes effect after this When using the MAXVCG process the roll angle and gust factor are automatically applied in the proper sequence Thus ROLL IMO WIND PRES SURE p HMMT WIND CONST GUST 1 5 SOLVE MAXVCG is all that is necessary Further the MAXVCG command automatically recalculates the wind moments at each new draft when they are based on the lateral plane Hence ROLL IMO HMMT WIND CONST GUST 1 5 MAXVCG produces maximum VCG curves for a stability criterion involving the ROLL angle If the ROLL angle keyword appears in a Limit it actually refers to the heel angle arrived at by ROLL For example LIMIT RESIDUAL RATIO FROM ROLL TO ABS 50 OR FLD 1 expresses the area comparison portion of
96. ndition of loading and operation GM gt PAH W tan T Where P 0 005 L 14 200 tons ft or 0 055 L 1309 metric tons m for ocean service Great Lakes winter service or service on exposed waters P 0 0033 L 14 200 tons ft or 0 036 L 1309 metric tons m for Great Lakes summer service or service on partially protected waters P 0 0025 L 14 200 tons f or 0 028 L 1309 metric tons m for service on protected waters L LBP in feet meters A projected lateral area in square feet square meters of the portion of the vessel and deck cargo above the waterline H the vertical distance in feet meters from the center of A to the center of the underwater lateral area or approximately to the one half draft point W displacement in long metric tons T either 1 the lesser of either 14 degrees heel or the angle of heel in degrees at which one half the freeboard to the deck edge in immersed or 2 fora sailing vessel T the lesser of either 14 degrees or the angle of heel in degrees to the deck edge The deck edge is to be taken as the intersection of the sideshell and the uppermost continuous deck below which the sideshell is weathertight b If approved by the Coast Guard Marine Safety Center or the ABS a larger value of T may be used for a vessel with a discontinuous weather deck or abnormal sheer c When doing the calculations required by paragraph a of this section for sailing vessel or auxili
97. near one end of the vessel the draft at the other end would show nearly all the change Of course there are other ways that the program might have been designed but causing the origin depth to go undefined avoids unnecessary complexity In many cases you will want to keep the displacement constant which is easily done with the SOLVE command as will be explained shortly If the vessel is upright or nearly so you can use the DRAFT command For example DRAFT 5 0 sets the origin depth such that the draft at the LCF is 5 0 DRAFT 20 5 0 sets the origin depth such that the draft at the origin is 5 0 Another useful form of the DRAFT command sets origin depth and trim simultaneously For example DRAFT 5 0 FP 5 5 AP sets both origin depth and trim such that the drafts at the FP and AP are as given Of course this requires that the LBP command has defined the FP and AP locations Literal locations can be used also If a DRAFT command similar to the example above is given with more than two locations it can define a nonlinear waterplane which we can use to represent hog or sag In that case GHS fits a parabola through the given drafts and reports the results showing any deviations from the parabola The draft at any location is always considered to be the average of port and starboard draft In other words it is the draft that you would find in the centerplane if you had a draft sensor at that point Since the draft measurement is taken with
98. ng libraries directly No optional modules are required WOD Water on Deck Wizard and Library New regulations for assessing the effect of water on decks of RO RO and ferry vessels are addressed in the WOD library and wizard No optional modules are required 78 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Topics for Advanced Training Tank Groups and transfers within a group Advanced Tank Types Damage Spilling Bubble WDF Flooded Plus Deck Water on deck criteria Water on deck wizard and WOD library LEw Weight categories GLM MAKER Axis heeling in all directions Rig stability Rig wizard Progressive flooding Intermediate stages of flooding FLDINTER wizard library Probabilistic damage DAMSTAB2 wizard Oil outflow Grain shift Maximum heeling moments MaxHMMT wizard and library Crane operations Crane wizard Crane criteria Ground reactions Launching Dry docking Multi Body Salvage procedures Submarine stability Advanced command language Templates Making wizards User tables User graphs Hopper spilling with mud lag 79 GHS Training Book Standard Course Rev 07 15 EXERCISE RUN FILES Importing the Barge Hull from a DXF PROJ MKBARGE IMPORT BARGE DXF BARGE GF NEWGF 3D XYZ SCALE 1 1 1 DISPLAY Making the Barge Appendages and Tanks PROJECT MKTANK READ BARGE GF ENTER PM ECHO ON UNITS F TITLE 40X16X6 BARGE COMM HULL CREATED BY MODE
99. ngly Here is the basic pattern for any Run File that reads existing geometry and performs calculations based on it PROJECT name READ filename GF REPORT repname PF REPORT PREVIEW REPORT OFF The purpose of the REPORT PREVIEW command as noted earlier is to allow you to see the report without printing it You can always print it later through the Report menu Annotating Run Files It is helpful to have notes in your Run Files information that will be ignored by GHS when it processes the commands from the file The left apostrophe above the Tab key on most keyboards is ignored as well as anything after it on the same line Printing Out the Geometry To get a hard copy of the geometry use the DISPLAY PRINT command READ FV GF REPORT FVDISPLAY PF Opens the report file DISPLAY PRINT NOOFF R R EPORT PREVIEW EPORT OFF Closes the report file The NOOFF parameter causes it to omit listings of the offsets There are many other parameters available as well which you can read about in the User s manual or through Help DISPLAY For example DISPLAY PRINT PREVIEW 30 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com gives you the on screen preview of the geometry hard copy report even when there is no report file open Caution If you simply give the command DISPLAY PRINT without a report file being open and without the PREVIEW the repor
100. nto consideration when determining the free surface correction may be one of two categories Tanks with fixed filling level e g liquid cargo water ballast The free surface correction is to be defined for the actual filling level to be used in each tank Tanks with variable filling level e g consumable liquids such as fuel oil diesel oil and fresh water and also liquid cargo and water ballast during liquid transfer operations Except as permitted in 4 5 1 and 4 6 1 the free surface correction is to be the maximum value attainable among the filling limits envisaged for each tank consistent with any operating instructions 4 4 Consumable liquids 4 4 1 In calculating the free surfaces effect in tanks containing consumable liquids it is to be assumed that for each type of liquid at least one transverse pair or a single centerline tank has a free surface and the tank or combination of tanks taken into account are to be those where the effect of free surface is the greatest 4 5 Water ballast tanks 4 5 1 Where water ballast tanks including anti rolling tanks and anti heeling tanks are to be filled or discharged during the course of a voyage the free surfaces effect is to be calculated to take account of the most onerous transitory stage relating to such operations 4 6 Liquid transfer operations 4 6 1 For ships engaged in liquid transfer operations the free surface corrections at any stage of the liquid transfer oper
101. o be an angle unless a slash appears along with the given number For example if you say TRIM 1 5a it takes this to mean 1 5 degrees of trim aft But if you say TRIM 1 5a 150 it assumes this to be a ratio of distances and computes the trim angle as its arctangent or 0 573 degrees If you have defined the LBP and want to base your trim input on that you can use the slash with nothing following it for example TRIM 1 5a Curves of Form Curves of form are form coefficients plotted against a range of drafts or waterplane levels Since the coefficients of form are intended to compare form characteristics of hulls or possibly other fair body objects they are available only for individual Components Hence in a Hull Part that includes appendages as separate Components it would be a main fair body Component usually HULL C but not necessarily so that would be a good candidate for curves of form The command to get curves of form is COMPONENT HULL HULL C FORM DEPTH di d dh where the d values are Reference Point depths of the Part s Reference Point not the coordinate system s origin though of course a Reference Point can be at the origin 35 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Why use Reference Point depths rather than origin depths or drafts Drafts are not used since they are not always well defined as discussed above Origin depths are not used beca
102. o the FLOODED type Of course a stability criterion appropriate to damage stability should have been established with the Limit commands Vessels that carry a significant portion of their cargo as liquids are not suitable subjects for maximum VCG curves with damage because the theory behind maximum VCG breaks down when a given initial condition is changed by the damage differently for different loads If damaged tanks are initially loaded the runoff will change the displacement and TCG of the vessel For this reason it is becoming more common for everyday onboard stability calculations to go back to first principles rather than using maximum VCG curves They are evaluating each loading condition by running the RA curves even including checking a large number of damage cases GHS is doing this in some of its onboard installations and does it fast enough even with very complex vessel models Since this is now possible there is little reason to continue to use maximum VCG curves Like cross curves curves of max VCG are being made obsolete by fast computers Other parameters called for by the stability criterion will need to have been specified also These might include heeling moments and Roll specification when dealing with weather criteria These will be covered later A MAXVCG Exercise Calculate Maximum VCG Curves using FV GF for displacements from 50 to 250 long tons by 50 LT increments and for a range of LCG va
103. of caution Nested Run files are not easy to manage and can become confusing They should be used only when there is a good reason The WRITE Command There are several forms of the WRITE command We encountered one of them when we were dealing with geometry Both Section Editor and Part Maker have WRITE commands that write Geometry Files In the context of the main program the WRITE command writes various forms of Run Files These are files that you can use later by issuing the RUN command For example WRITE SAVE ABC DAT will write a file named ABC DAT that contains all the commands necessary to restore the state of the program to its current state In other words it has the READ command to bring in the geometry commands like HEEL and TRIM to restore the waterplane etc 40 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com The file name extension DAT was used in this case to distinguish it from ordinary Run Files This is merely a convention and not a requirement It could have been named ABC RF Then when you want to restore everything to the way it was at the point when you did the WRITE command simply issue the command RUN ABC DAT There are other more specialized files that the WRITE command will generate as we shall see later Stability Criteria Introduction to the Limit Command GHS provides for stability criteria through the LIMIT command Various properties of t
104. ooding since the angle of downflooding normally does not increase much when the VCG is lowered How low does it attempt to bring the VCG No lower that the initial VCG setting This is called the Floor VCG You can use the VCG command to set the floor before you issue the MAXVCG command For example VCG 5 0 If you take the trouble to specify a floor value that is not so low as to be unreasonable it will speed the MAXVCG process 42 GHS Training Book Standard Course Rev 07 15 Creative Systems Inc www ghsport com There are cases where it is impossible to satisfy all of the Limits while having one limit be zero This is caused by discontinuities in the Limit values as a function of VCG For example there are cases where it is impossible to find a VCG that gives a certain value to the area up to the maximum RA because the the RA curve is flat on the top or has two equal peaks and one gives an area value greater than required and the other gives a lesser value The MAXVCG command assumes that the vessel has port starboard symmetry with respect to its center of gravity If any tank loads or other weight declarations exist from prior commands they will be ignored The parameters of the command specify what displacements are to be used therefore light ship and existing loads are irrelevant All that is needed in order to generate maximum VCG curves with damage is to have used the TYPE command to set one or more tanks t
105. or example to change the reference point of a Part named HULL the command would be REFPT HULL I t v Remember the discussion about system variables These are certain values internal to the program that are accessible to the user One of them is the height relative to a 32 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com waterplane of the Reference Point of the given Part This is accessed through the HEIGHT system variable For example PART HULL MESSAGE Height of HULL Ref Point is HEIGHT Notice that we had to establish HULL as the Current Part by means of the PART command so that the program would know which Part we were interested in The Current Parts List In many occasions you will need to address a certain Part or a certain collection of Parts One way to do this is to make use of the Current Parts list As we saw in the previous section the PARTS command does this Note that the Current Parts list shows up at the bottom of the screen at least it shows as much of it as will fit in the space available The list itself is not truncated only the display of it may be incomplete Some commands act on certain Parts Generally there are two ways to tell the program which parts you want it to act upon One is simply to provide the name or names of the Parts right in the command that will be acting on them This is always the first parameter of the command and in
106. orth reading the User s Manual section entitled Understanding the Model in the GHS System Overview There you will find a diagram that shows the Components of two tanks sharing the same Shape The Vessel Coordinate System The ship model uses a 3 D Cartesian coordinate system but rather than refer to the axes as X Y and Z we call them L T and V Longitudinal Transverse and Vertical and they always appear in that order The sense of these axes is positive aft positive to starboard and positive upward We can also denote the longitudinal by means of a letter suffix For example 10 0 would be 10 0 units of length forward of the origin but it could also be denoted as 10 0f Likewise 10 0 could be written as 10 0a Similarly in the transverse direction p and s suffixes can be used Especially in reports the f a and p s suffixes are used so that the reader does not need to remember the GHS sign convention The origin of the coordinate system i e the point 0 0 0 is usually located near the keel in the plane of transverse symmetry and at one of the perpendiculars In other words it is usually located the same as on the original lines plan or hull model The base plane by definition runs through the origin as does the center plane But this is only terminology and you are free to locate the origin anywhere you choose Remember that ultimately the model may be used in an on board GLM where the shipboard personnel will
107. ow a certain near empty level and true FSM above that 8 true FSM subject to a floor value 9 true FSMs subject to a floor values for each type of substance in certain tanks 10 any of the above subject to an overall floor FSM 48 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com GHS allows you to use any of these methods The FSMMT and FSMFLOOR commands apply The FSMMT command allows you to assign two FSM methods to each tank and the FSMFLOOR command provides for assigning the floor values to certain tanks as well as an overall floor value There is some reason behind all of these options though only one of them has to do with being more realistic The others are about a conforming to old methods that date back to the days of slow or expensive computing methods or b trying to build in an extra safety margin that recognizes the development of additional free surface relative to the current condition Ironically there are cases deep tanks where the CG shift method gives a more pessimistic stability result than some of the FSM methods One of the FSM methods that you can assign to any tank is MAX The command FSMMT FO MAX finds the loads in the named tanks where the FSM is maximum and assigns those FSMs to the tanks as fixed values It does this at the current heel and trim angles A side effect is that it leaves the tanks loaded where it found the maximum FSMs Therefore it is best to do t
108. p as expected After providing this information simply issue the LS command to get a table of the LS results including shear bending moment and optionally deflection There are some options about what is to be included in the table One of the options is to show the results only at specified frame locations A special Frame File provides frame names and locations See the HELP LS for more information about the options and about preparing the Frame File An LS Exercise Make a Run File to produce a longitudinal strength curve using TANKER GF and the weight curves shown above tank loads and a wave Include the SMOD command and get deflection If you want to use the Load Editor to set up your tank loads you can do it in two phases with two Run Files arranged as shown below The first run sets up the load condition saves it to the file LS1 DAT The second run picks up LS1 DAT establishes wave and generates the report ROJECT LS1 EAD TANKER GF PEGE L es MOD 4000 OAD EDIT E LS1 DAT D lt E 00 E O zi Wy z D IU ROJECT LS2 70 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com RUN LS1 DAT CALL REPORT LS with Waves WAVE 0 100 SOLVE DISPLAY STATUS PROFILE OUTBOARD PROFILE LS REPORT PREVIEW REPORT OFF END Floodable Lengths After setting up a condition the FL command will produce a series of floodable len
109. parameters on the GHS SOLVE and RA commands 49 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Hydrostatic Properties Several commands produce reports of hydrostatic properties in the current condition It need not be a realistic solved condition The only requirement is that the waterplane be defined Here are the commands and a brief description of what you can expect to get from them HS This is the pure hydrostatics report that is entirely independent of the CG GHS This is similar to the HS report but it takes the CG into consideration and shows GML and GMT If the CG is not on the BM line it assumes a CG position that puts it on the BM line without changing the VCG The optional GMRA parameter causes it to get the GM from the righting arm curve but only when it is in equilibrium STATUS This command has many options and is frequently used The recommended form is STATUS GHS which presents all the information that you would get from using both STATUS and GHS but in a more compact form since nothing is duplicated The rightmost column in the standard STATUS report shows Reference Point heights which you may not need and in that case you can eliminate it by including the NOREF parameter Alternatively you can get FSM in that column by including the FSM parameter There are 18 categories of information that you can get from the STATUS command If you want a certain mixture of them it i
110. pect to their distance from the waterplane The most common use for these points is marking places on the vessel where some significant downflooding would occur if the point were to become submerged even briefly Therefore when you define a critical point it is assumed to be a downflooding point we call it a Flood or FLD point unless you specify otherwise 41 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com The CRTPT command defines critical points Each Critical Point has a number which is enclosed in parentheses For example CRTPT 1 Engine room vent 22 85f 5 50 16 5 This defines Critical Point 1 If there was already a Critical Point definition in the 1 slot it is replaced with this new one In addition to the number you must supply a brief description in quotation marks A related form of the Critical Point is used to mark weathertight points places where downflooding would be significant if the point were permanently submerged These we call TIGHT points For example CRTPT 3 Main hatch side 8 0f 5 3 14 5 TIGHT In some of the LIMIT commands above you will notice the FLD keyword appears This means that the program is to check for any critical points that become submerged and to give no credit for stability beyond that heel angle In other words the criterion expects there to be sufficient energy in the righting moment curve prior to the immersing of any downflooding point
111. r is less and 6 An area under each righting arm curve between the angles of 30 degrees and 40 degrees or between 30 degrees and the downflooding angle if this angle is less than 40 degrees of not less than 5 6 foot degrees 1 72 meter degrees c Each vessel must have 1 An initial metacentric height GM of at least 0 49 feet 0 15 meters 2 A maximum righting arm that occurs at an angle of heel not less than 15 degrees An area under each righting arm curve of at least 16 9 foot degrees 5 15 meter degrees up to an angle of heel of 40 degrees or the downflooding angle whichever is less 4 An area under each righting arm curve between the angles of 30 degrees and 40 degrees or between 30 degrees and the downflooding angle if this angle is less than 40 degrees of not less than 5 6 foot degrees 1 72 meter degrees and 5 An area under each righting arm curve up to the angle of maximum righting arm of not less than the area determined by the following equation A 10 3 0 187 30 Y foot degrees A 3 15 0 057 30 Y meter degrees where A area in foot degrees meter degrees Y angle of maximum righting arm degrees 63 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com 46 CFR 170 170 Weather Criterion 170 170 Calculations required a Each vessel must be shown be design calculations to have a metacentric height GM that is equal to or greater than the following in each co
112. s data file for exchange of geometry definitions between marine software products SHC Ship Hull Characteristics Program data file Contains a hull description If bulkhead offsets are included a Part Maker Run file can be written to create the compartments thus described Conversion from GF to SHP is not available OFE Offset Editor file format used by some hull design software SHP HUL CMP CMA Herbert Engineering Corp file format Hull geometry and tank geometry information may be found in separate files Model Converter will read certain of these files and write the result to a GF file Conversion from GF to HEC is not available EAG A simple hull definition file originating from the PIAS software Model Converter FIXUP Mode FIXUP command In this mode Model Converter provides a rich set of operations that you can perform on your Geometry Files For example you can have it change add or delete sections define deck edge specify margin or specify shell thickness When directed to do so it can also delete all tanks delete all parts except tanks and reorder the sequence of tanks Some of these operations are also available in Section Editor and Part Maker Model Converter is especially useful as a command in a Run File which leads to a greater degree of automation in your work We will learn more about Model Converter later Section Editor SE command Section Editor can be used to edit Components and Shapes You can a
113. s relative to ships coordinates Excessive trim shown for clarity 15 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Model Building Creating the Geometry The tools essential to the process of creating and modifying geometry are Part Maker ENTER PM command Part Maker is typically used for building tanks appendages and superstructure into Geometry Files that have an existing hull Part It can be used to create hulls but if the hull is of ship shape form Model Converter or Section Editor would be a better choice Other hulls that consist primarily of cylinders and rectangular shapes can be created quite efficiently using Part Maker alone Components of Parts typically tanks and superstructure are created by specifying simple boundaries and then trimmed to the required shapes by fitting to existing Components For example if given the end bulkheads the inboard bulkhead the top and the bottom boundaries a wing tank can be easily fitted to the hull We will get into the details of actually using of Part Maker later Model Converter MC command or IMPORT and EXPORT commands Model Converter is used to import and in some cases to export the following files which are listed here under the file name extensions that Model Converter recognizes GF GHS geometry file DXF Drawing eXchange File commonly available from CAD programs IDF IMSA International Marine Software Associate
114. s usually better to specify them all in one STATUS command since the report will be more compact than if you give separate STATUS commands However the order in which they are reported is fixed regardless of the order in which you specify the categories LOAD tanklist STATUS TANKS This produces a report that is similar to the presentation in the Tanks screen of the Load Editor It omits centers of gravity but includes Part descriptions which are absent form STATUS reports With petroleum loads you can get gross and net volumes depending on temperature LOAD STATUS FIXED This report is similar to the presentation in the Weights screen of the Load Editor DISPLAY tanklist STATUS This is the Condition Graphics report which is a graphical representation of the current status and is very effective when used immediately after the STATUS command In most cases you will want all tanks that have any loads in them or that are flooded to be shown and so the command would be DISPLAY STATUS By default you get plan and profile views There are many other options that you can read about in Help CG Deadweight There are two ways to get a deadweight report through the STATUS command The STATUS DW report includes a Deadweight Status line showing the difference between total displacement and total light ship It always includes the displacement at the current waterplane 50 GHS Training Book Creative Systems Inc Standard Course Rev 07 1
115. t will be sent to the printer immediately which can consume a great amount of paper This printout can serve as documentation of a particular Geometry File Annotating Reports You can place text and graphics in your report by means of the NOTE command This command has a special abbreviation the back slash For example Case 3 Arrival This places the text Case 3 Arrival on the current line of the report file starting at the left margin To have it centered horizontally in the line put another back slash at the end Case 3 Arrival An advantage of using the back slash rather than NOTE is that it preserves the case NOTE capitalizes everything There are many other features of the NOTE command including its ability to place a graphic image in the report Look in HELP NOTE for all the details The MESSAGE Command This command has many uses The most basic one is to place a message on the screen For example ME Hello GHS Try this and you will find HELLO GHS on the screen Note that everything became capitalized To prevent the capitalization start your message with a quotation mark no need to put one at the end ME Hello GHS System Variables Certain information internal to the program is accessible to you without having to take it from reports The means of accessing this information is the System Variable For example there is a System Variable named PROJECT You get whatever information is currentl
116. te EO ee ete ERR diee ege Ee RR RRRA 35 Curves Of FON eec et tetro bete eie trees o rotta Ux Te SEERA RATA Pe nas 35 Flooding Tanks ede teet egeo un poe v teneo vetet evo VE E Prae 36 DE H URHEEPEERES 36 Curves of Hydrostatic Properties ennt 37 An Exercise in Curves of Hydrostatic Properties ssssssseeeeennnees 37 More About Station Spacing sssssssssssssssss esee enne rennen 37 Choosing your Drafts saraje Lh e densi oec asa ai dara radodarni ede paste re eia 38 Cross Curves of Stability ener ener 38 Elem LEE 39 Nested Run Files itii ti eae dise 40 The WRITE GOmMand s ERR 40 Stability Criteria Introduction to the Limit Command sssssee 41 Critica ROMS ERE 41 AMAXVGCG EXGICISG eese eter te RM UR Ent denr ned epe adaa N do a ra Gunns bed AAEN aadi 43 Composite Maximum VCG QCurves sse entente nennen 44 A Exercise in Composite Max VCQ ssssssssssssseseneeeeneen nennen nennen 44 MAXVOQEOONUD sete mte etti test esc dee 45 Specific Conditions Setting Up a Waterplane sse 46 Draft SUtVeyS e serere tte ouibus E A 46 Tank OAS Sete ute hene ied Uie to 47 Coefficients of Form Wetted Surface and Sectional Area Curves s 47 Free Surface and Free Surface Moments sss 48 About GM Sion nee ce Aie erbe iE ene er earn Mts Ee 49 Hydrostatic Properties ni ate t ER EE REO Rate
117. than one line of text The first line starts with CREATE and the last line is a single forward slash The lines between the CREATE and the terminating slash look like additional commands but since they are within the multi line command we call them Statements They are essentially parameters that define what is to be created Here is an example of a simple Part Maker run to create a double bottom tank on the starboard side with its top at 2 5 ABL and extending from the centerline to the shell ENTER PM READ OLDSHIP GF CREATE TANK1 S ENDS 12 34f 4 56a TOP 2 5 FIT HULL HULL C WRITE NEWSHIP GF QUIT PM It is assumed that the hull geometry at least was already present in the GHS main memory causing the file that it came from to be read into PM by the ENTER process This example generates not only the new Part TANK1 S it also generates the first Component within the new Part Since we did not specify the Component name it becomes the same as the Part name The Component s Side of course is starboard It also creates the Shape to carry the actual offsets most of which were derived from the hull in order to give it the proper shape where it is bounded by HULL C It is was not necessary to declare the Class in this example because class TANK is the default There is a Part Maker tutorial at www ghsport com support tutor pmtut and you may also find it included in your GHS Help system From
118. the Help menu select Web Help then GHSport on disk then select Customer Support then Tutorials and finally Part Maker Tutorial 27 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Under the Help menu you will find PM which is the summary reference document for Part Maker At the end of that document is an alphabetical list of the Part Maker commands and statements The Help entry PM TM explains in detail about making tanks and PM AM similarly covers appendage making with Part Maker A Part Maker Exercise Using the barge hull created in the second Model Converter Exercise above add the hull Components THRUSTER and SKEGS and also the compartments and independent tanks shown in the drawing below Here is a start for the Run File PROJECT MKTANK READ BARGE GF ENTER PM ECHO ON UNITS F TITLE 40X16X6 BARGE COMM HULL CREATED BY MODEL CONVERTER FROM BARGE DXF COMM TANKS ADDED PER TANK DWG CREATE HULLNTUNNEL P DEDUCT CIL 8 05 25 5 Bic Bin by Iu FIT HULL CREATE HULLNSKEG C ENDS 34 39 TOP 4 BOT 0 IN 4 OUT 5 FIT HULL CREATE REMAINING TANKS PER SKETCH UNITS M WRITE BARGE GF1 DISPLAY QUIT PM 28 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com 0 5 x amp
119. the perpendiculars automatically from the geometry If you want it to acknowledge these locations you must declare them explicitly be means of the LBP command In the simplest form of the LBP command you can simply specify the length between perpendiculars This is useful for enabling the representation of trim as a distance instead of an angle Or you can give the FP and AP locations using the command in the form LBP Lip Lap where the L values are longitudinal locations in the ship s coordinate system Trim Angle vs Trim Distance Although trim is fundamentally an angle it is often more convenient to represent it as the difference between forward and aft drafts However this is not a precise definition unless the ship is at zero heel Exactly how does GHS represent trim as a distance It simply takes the tangent of the Trim angle and multiplies it by the LBP After the LBP has been defined the reports will show trim as distance and also mention the LBP length so that there is no question about the length If FP and AP have both been defined some of the reports will show drafts at both points rather than trim In that case the trim distance will not be exactly the same as the difference in those drafts unless the heel angle is zero This follows from the definition of Trim given above Trim is based on the heeled waterplane while draft is to the ship s baseline What about trim input When trim is involved in any command GHS expects it t
120. there will always be Acommand name possibly abbreviated One or more parameters following the name usually Regarding the parameters The order of the parameters is often significant Certain parameters must be enclosed in parentheses if they appear at all Some parameters must be enclosed in quotation marks Some parameters must begin with a slash The case used in commands and parameters does not matter it can be either upper or lower case or a mixture of upper and lower Changing the Working Folder The path to the current working folder is shown on the left side of the status bar at the bottom of the GHS window To switch to a different working folder use the File menu and its first selection Change directory Top field new working folder Double click new folder when desired folder appears in the top field Click Select Change directory E F GHS Training Basic x Setting the Project Name Cancel Double click to move up a level Select drive The command PROJECT name defines a short 8 characters maximum name that appears at the top right corner of the GHS screen and in a similar location on every page 10 GHS Training Book Standard Course Rev 07 15 Creative Systems Inc www ghsport com of the reports It also forms default file names Once the project name is defined you can enter the direct command EDIT or s
121. tion from the baseline in the counterclockwise direction Heel angles can range between 180 degrees 33 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com to port and 180 degrees to starboard The HEEL command sets the Heel angle For example HEEL 10 sets the Heel at 10 degrees to starboard The Trim angle is best visualized on the same body plan The lines cutting the sections are parallel to one another and the more trim you have the greater the distance between them From any two sections you can calculate the Trim angle by taking the arc tangent of the distance between the water lines divided by the distance between those two sections The sense is positive for aft trim when the water line on the section further aft is above the other Trim angles can range between 90 degrees forward to 90 degrees aft The TRIM command sets the trim angle For example TRIM 2 0 sets two degrees aft trim without affecting the Heel angle Origin Depth vs Draft The waterplane is specified and reported primarily by means of three parameters Trim angle Heel angle and origin depth The origin depth is the distance between the waterplane and the coordinate system s origin 0 0 0 This distance is taken perpendicular to the waterplane and it is positive when the origin is under water negative if the origin is above the waterplane Draft is not the same as the origin depth for three reasons 1 Draft is always me
122. uilt in Help system that can be used by anyone who is new to the program or has forgotten what was learned in training Any time the menus are active the Executive can be quickly brought up since it is the first item in the Wizard menu It can also be brought up via the command RUN EXECUTIVE WIZ The automatic appearing of the Executive at program start up can be turned off and on by the Executive itself Press the Executive s Help button and at the top of the Executive Help screen are buttons for turning the automatic appearing on and off Automatic Start up Run Files There are two special Run File names that GHS looks for at program start up time and runs them if they are found GHS LF If present in either the working folder or the User Library folder file GHS LF will run automatically at program start up time This feature could be used to set printer options for example It could also set any of the screen options discussed below Of course this file does not have to exist at all for most users the defaults are fine and GHS LF is not needed GHS SAV If present in the working folder the User Library folder or the GHS program folder file GHS SAV will run automatically at program start up time This feature could be used just like GHS LF though GHS LF is preferable most cases Note that if either of these special start up files exist the Executive dialog will not appear unless t
123. use curves of form are not limited to hull Parts Even tank Components can have their curves of form in which case it is the waterplane within the tank not the vessel s draft that is relevant Curves of form are available at any trim and heel angle The first parameter in the COMPONENT command is actually optional The default is to repeat the calculations for each Component of each Part in the entire model However if one or more Current Parts have been defined by means of the PARTS or TANKS command these reports are limited to them Flooding Tanks Tanks can be intact or flooded When flooded they become negative displacers since they are considered to be open to the sea In other words they see the same waterplane that the hull sees but instead of making a positive contribution to displacement they subtract from it The command to switch a tank from Intact type to Flooded type is the TYPE command Initially all tanks are intact To make a particular tank flooded the command is TYPE tankname FLOOD then to restore it to the intact type TYPE tankname INTACT In both cases tankname can be a list of tanks separated by spaces or commas and each member of the list can end with an asterisk to match all tanks whose names have a common beginning This is especially useful when you want to make sure all tanks get restored to intact TYPE INTACT Waves GHS allows you to specify a wave profile that gets superimposed on th
124. ve a look at it Since DXF files 24 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com are text files you can view it as text using the VIEW command VIEW HULL DXF Much more useful would be to look at the DXF through a drawing program that reads or imports DXFs If you have one on your computer you might want to take a look at this drawing that Model Converter has created As you may have guessed the parameter 3D XYZ has something to do with the way the drawing is laid out It tells Model Converter to make a 3D drawing and to make the drawing s X Y and Z axes correspond to the L T and V axis of the GHS model Now let s complete the exercise by doing the following First add a second EXPORT command to your run file this one exporting the Component HULL FOCSLE C to the file FOCSLE DXF Next put the command CLEAR This will clear the geometry from main program memory so that we can be sure that what we see next will actually be what was imported Follow this with an IMPORT command to take the drawing data from HULL DXF and place it on the Geometry File FV1 GF Now the command needs to be more explicit The EXPORT command needed only to state the name of the file to receive the output implying that the currently read Geometry File would be the source Now we must specify both the input or source and the output file The command would be IMPORT HULL DXF HULL HULL C FV1 GF 3D XYZ NOFILL
125. will generate suitable DXF files the easy way simply by using the EXPORT command We will export two components from the FV GF model as two separate DXFs then import them back into a singe Geometry File If you have a CAD program on your computer you can look at the DXFs that we will be generating This is a good time to use a Run File We will place the EXPORT and IMPORT commands in a Run File named MKHULL RF Atthe GHS main program prompt enter the command PROJECT MKHULL Then enter the command EDIT This should bring up the Run File editor ready to create or edit MKHULL RF The first thing to put on this file is that PROJECT command again This will save some time if you come back to this file later since it will define the project name itself when your run it Next we will use the READ command to read FV GF into main program memory Then type in the EXPORT command as shown below PROJECT MKHULL READ FV GF EXPORT HULL HULL C HULL DXF 3D XYZ You can now close the editor saving the file first and when you get back to the GHS main program command prompt enter the command RUN Since the project name is MKHULL it will run MKHULL RF Unless you include the NOWAIT parameter there will be an informational MC window that you will need to close before it will continue The result of this run is the file HULL DXF and you will find it in the working folder If you are familiar with the DXF format you might like to ha
126. will shift the sail 0 5 units aft of where it was originally Other SE Commands To quit Section Editor and go back to the main program use the Quit command or press the Escape key which will bring up a prompt to confirm quitting Other interesting SE commands include Delete Component the Part is also deleted if it has only one Component Edit changes Component parameters Effectiveness Margin and Vector Location relocates a station optionally moving neighboring stations to Lengthen or Shorten the shape Title adds a title to be saved with the geometry file Xlate toggles translate mode In this mode moving a point moves the entire station A list of Viewing and Editing commands for Section Editor are provided below for Reference The Viewing commands also work in Display 21 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Section Editor Display Viewing Commands Change view TAB cycles through view plan profile isometric body plan profile SHIFT TAB toggles view profile lt gt plan OR body e isometric ENTER toggle views plan profile isometric ALT lt t rotates model in isometric view Viewing Options CTRL B toggle background color black white CTRL K toggle deck edge and centerline display on amp off CTRL L toggle single station lt all stations in single station mode F7 amp F8 display adjacent stations CTRL O toggle
127. y held under the name of a System Variable by enclosing the name in braces sometimes called curly brackets For example PROJ RIVERQ ME The project name is PROJECT Compared to report output this is a more intimate way of communicating with the program It may not be obvious now but eventually you will find it quite useful 31 GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com Two Kinds of Calculations There are two kinds of calculations Those that do not require a particular condition or load and those that are based on one particular condition The calculations that are independent of any particular load condition typically result in a table and graph of some vessel characteristic as a function of displacement or load This includes curves of form hydrostatic properties cross curves of stability maximum VCG curves and tank characteristics curves In a slightly different category but of the same kind are those that are entirely independent of any waterplane Component skin area and tonnage Those calculations that are based on a specific condition include the status report of particular hydrostatic properties righting arm curves maximum VCG in a particular condition longitudinal strength curves and floodable length curves Parts and Components in the Calculations As mentioned earlier one reason for the hierarchy of Parts and Components is to simplify the presentation in
128. you access through these menus are also available through commands In fact when you make a selection from a menu the equivalent command appears on the Screen the menu mechanism actually generates and runs the command That means GHS Training Book Creative Systems Inc Standard Course Rev 07 15 www ghsport com you can place any of those commands in your run files to produce the same action that you would get through the menu If there is a dialog box active such as the GHS Executive discussed below you will have to close it before you can access the pull down menus The menu that you will find most useful is Help which provides quick access to nearly all of the GHS User s Manual It is organized by command name making it easy to look up the description and parameters of a given command There is also a global search allowing you to search the entire manual for any word Help opens a separate window that stays open until you deliberately close it even after closing the GHS session Right click anywhere in a Help window to bring up the index Printer Setup GHS will use your Windows default printer unless you direct it to use another one You will notice there is a separate Report menu where all of the report functions including printing are grouped together rather than being in the File menu as you might expect If you want to change the printer that GHS will be using use Setup Printer at the bottom of the Report menu

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