Questions and Answers

General Hydrostatics & Stability , Error Messages & Conditions, Geometry & Model Building, Longitudinal Strength, Load Editor & GLM, Maximum VCG & Stability Criterion, Probabilistic Damage, System, Tanks & Free Surface, Wind & Wave, Seakeeping

General Hydrostatics & Stability Questions
File Title Updated
QA002 What about stability in various directions other than the beam? 11/97
QA020 The GHS and HS commands - How do they differ? 11/97
QA021 Does RAH /FSM change the equilibrium angle? 12/97
QA022 Proper use of the SOLVE with the RA command. 12/97
QA025 Displacement in Curves of Form is incomplete. 12/97
QA029 Why does trim not always equal aftD - fwdD ? 12/97
QA032 What about grain heeling moments? 12/97
QA033 Can progressive flooding be simulated? 12/97
QA035 How is deflection modeled? 12/97
QA055 Running the RA command against Limits. 3/98
QA057 Using the ADD and GROUND commands to define ground reaction. 3/98
QA058 Can GHS calculate the ground reactions only when ground points are given? 3/98
QA067 Displacement in a damaged condition: Status Report. 3/98
QA068 Origin Depth and draft, an explanation. 3/98
QA071 The correct use of the HMMT command. 4/98
QA072 The reason for LCF and Moment to Trim lines being wobbly. 7/98
QA076 The correct syntax of AREA LIMITS. 7/98
QA080 How to calculate 46 CFR 173.025 - Crane lifting with counterballast. 8/98
QA081 How to combine two functions of heeling moments. (Turning + Wind) 9/98
QA082 Why is trim held at zero in free to trim cross curves? 10/98
QA084 Finding the "weakest axis" for a specified condition. 10/98
QA090 Evaluating the Water on Deck Criteria for
Fishing Vessels as specified in 46 CFR 28.560
QA091 How does GHS Calculate Heel Angle in a Condition Containing a TCG? 09/99
QA093 How can I calculate longitudinal righting arms with GHS? 11/99
QA094 Why does the GHS /KM command eliminate deflection? 11/99
QA096 Defining GHS LIMITS for 46 CFR 172.065g section 2 03/00
QA098 A macro for obtaining hydrostatics with fixed LCG and varied trim. 03/00
QA100 How to obtain the actual values of the areas under the RA & HMMT
curves instead of just the residual ratio?
QA103 An explanation of the differences between DEPTH and DRAFT 06/01
QA104 I need to have a spilling tank that once the spill point submerges sea water fills in above the level of cargo to the external waterline. 07/01
QA106 If my geometry file has shell thickness applied how do I ensure that Block Coefficients are using molded volume? 08/01
QA107 Why is the Delta Weight not zero after a Solve command? 09/01
QA108 How to delete ADDed weight items that are associated with lightship. 11/01
QA109 Why does SOLVE sometimes give different answers for the angle of equilibrium? 12/01
QA111 Why are Limit margin evaluations sometimes reported as LARGE? 2/02
QA113 Why does the GHS output sometimes show Moment per degree trim and other times Moment/inch trim? 3/02
QA115 Why does GM sometimes show in RA plots and not in others? 3/02
QA120 Using ground points for an ice breaker case. 01/03
QA123 How do I model the hook load suspended from a crane? 03/03
QA126 What does "True Free Surface Included" mean? 02/05
QA133 Do you have any guidance on modelling a specific ground bearing strength? 04/08
QA138 How can I tell if my geometry model has a shell thickness? 05/11
QA146 How to verify a residual ratio limit. 05/16
QA171 Calculate Residual Ratio from RA table values. 05/16

Error Messages & Conditions

File Title Updated
QA004 How can I avoid the "Need closer angles" error. 11/97
QA007 What is the "Corrupt Data" error when reading geometry files? 11/97
QA078 Does the message UNDEF mean my margin line is under water? 8/98
QA087 How do I avoid the Negative Waterplane error message. 11/07
QA105 How can I prevent the error "roll angle must be first" for Wind and Rolling calculations. 07/01
QA125 What causes "Invalid Argument" in Floodable Lengths? 01/05
QA131 When I try to use Part Maker it says, "NTVDM.EXE has encountered a problem and needs to close." What can I do? 11/07
QA118 "GHS system halt : version disagrees with key,"
"GHS Hardware Lock Required"
QA166 I installed Part Maker version 16.50 and my runfile now returns the error: "Ambiguous Component."
What does this mean?

Geometry & Model Building Questions

File Title Updated
QA001 How to combine two geometry models (for example, Barge + Rig). 11/97
QA006 Adding superstructure, calculating buoyancy & effect of flooding. 11/97
QA010 What is the difference between Parts and Components? 11/97
QA012 Assigning permeability to deducting components. 11/97
QA013 Buoyancy of timber on deck. 11/97
QA015 Can you create a hull with Part Maker? 11/97
QA018 Does GHS do interpolations on the geometry model? 11/97
QA024 How to fit tanks with a separate 'tweendeck component. 12/97
QA036 Proper use of the Model Converter /3D parameter. 12/97
QA039 How to make floodable superstructure. 11/97
QA044 Should a bulb be integral with the hull component? 11/97
QA059 Using LOCUS statements to create an unsymmetrical tank. 3/98
QA066 Fitting appendages to a hull with the required Station Overlap. 3/98
QA069 Using the Arc command in Section Editor 3/98
QA073 To what locations do the three Margin values refer? 7/98
QA074 How can I keep the Margin Line from following a lowered deck edge? 7/98
QA077 How to create a Deck Margin and how it relates to downflooding in GHS. 8/98
QA086 How to print a vessel model display from GHS. 11/98
QA087 How to avoid Negative Waterplane errors when deducting components. 12/98
QA089 How to use Model Converter to set varying deck margins. 2/99
QA092 How to model a vessel that has split in two pieces. 11/99
QA099 Modeling a hopper-barge which is loaded with rocks. 3/00
QA104 I need to have a spilling tank that once the spill point submerges sea water fills in above the level of cargo to the external waterline. 07/01
QA114 Tank Soundings doesn't want to read my GHS model, what is wrong? 03/02
QA123 How do I model the hook load suspended from a crane? 03/03
QA130 Why can't I write a .GF in Part Maker that I have read imported, changed, and added tanks to? 03/03
QA135 How can I get hydrostatic data without a geometry model? 09/08
QA140 What is the optimal number of vertices to use in a cylinder command? 05/17
QA167 How can I strip the existing critical points from the hull model? 02/20

Longitudinal Strength Questions

File Title Updated
QA119 Getting LS Deflection results to match field results. 11/02
QA124 How can I get frame names to display in LS? 1/05
QA144 How can I get deflection data in the longitudinal strength calculation reports? 7/14

Load Editor & GLM Questions

File Title Updated
QA047 Is GLM suitable for Container Ships? 12/97

Maximum VCG & Stability Criterion Questions

File Title Updated
QA009 MAXVCG with Passenger Crowding. 11/97
QA017 How to vary the limit on area under righting arm curve. 09/15
QA019 MAXVCG with center of gravity off centerline. 11/97
QA028 What do "P" and "F" mean in the attained limits. 12/97
QA041 About LIMIT with three terminating angles. 11/97
QA070 Setting the Maximum VCG before running the RA command. 3/98
QA075 Does MAXVCG always regard the Margin Line if present? 7/98
QA085 An explanation of the Margin % in Maxvcg output. 11/98
QA121 How the Maxvcg iteration process works. 01/03
QA122 Using Deck Immersion Limits with MAXVCG 01/03
QA127 MAXVCG command vs. SOLVE MAXVCG command 03/05
QA128 Drilling unit weakest axis 04/05
QA136 DNV crane criterion for accidental load drop 05/09
QA145 Analyzing Maxvcg results with non-zero margins. 05/16

Probabilistic Damage Questions

File Title Updated
QA040 Maximum RA in DAMSTAB vs. RAH 12/97
QA117 Interpreting the Damstab trace file 7/02

System Questions

File Title Updated
QA005 When do new pages start? 11/97
QA011 What is a Run File? 11/97
QA014 Using a macro to simplify a run file. 11/97
QA053 Developing a calculation Macro. 3/98
QA079 Retrieving and placing the value for RA0 in a variable to use in other equations. 8/98
QA102 How to get the geometry file name or other information to appear on each page of GHS output. 5/01
QA110 How to control page numbering between several report files. 1/02
QA116 Long file name compatibility between GHS and Part Maker. 4/02
QA118 I'm having trouble installing GHS. 11/07
QA132 How to turn the GHS Error Beep on and off. 11/07
QA137 How to prevent the WINDOWS Security Warning window from popping up when GHS starts. 12/09
QA139 How to find the number of a GHS security dongle. 01/14
QA141 Is there a way to extract the righting arm plot from a report? 06/16
QA142 Column formatting problems using variables in a summary report. 06/16
QA147 Can I write a TAB character to a file using the ME command? 03/17

Tanks & Free Surface Questions

File Title Updated
QA008 Does FSM affect the equilibrium angle? 11/97
QA021 Specifying FSM for the RA command. 11/97
QA048 Differences between Flooded and Damaged tanks. 3/98
QA049 Including Free Surface in tank tables using the TC command. 3/98
QA050 Finding The exact ullage at zero volume. 3/98
QA056 Free surface moments in GHS. 3/98
QA097 What is the best way to model hoppers for a hopper-dredge barge? 3/00
QA101 When a tank is frozen, how does the software account for this weight when calculating righting arms? 01/01
QA104 I need to have a spilling tank that once the spill point submerges sea water fills in above the level of cargo to the external waterline. 07/01
QA112 How is the VCG adjustment that appears in RA /EXTRAFSM derived from FSM? 02/02
QA129 Inclining with water in bilge. 05/05
QA134 GHS does not give the expected result when converting API60 to specific gravity. Why? 04/08
QA143 What do you recommend with regard to calculating the FSM for a tank cross connected at the top? 07/14

Wind & Wave Stability Questions

File Title Updated
QA016 Wind heeling for Drilling Units. 11/97
QA083 Calculating a midship wave when the origin is not at the FP, AP or midships. 10/98
QA095 Waves and small craft stability. 12/99
QA169 Which parameters go with which HMMT WIND methods? 09/23

Seakeeping & Wave (spectra) Questions

File Title Updated
QA148 How many samples should I use? 12/18
QA149 RMS, average, significant, maximum, extreme: Which amplitude should I use? 1/20
QA150 What is the difference between the Zero-Up-Crossing period (PERZUC) and the period between maxima (PERMAX)? 12/18
QA151 My RAOs look weird, what do I do? 12/18
QA152 When should I adjust the LF and/or BF? 12/18
QA153 Why are the rotational RAOs always the same for any point on the vessel? 12/18
QA154 What does the COUPLE parameter do? 12/18
QA155 Viscosity: what does it affect and how do I change it? 12/18
QA156 Does SEA output the uncoupled motions, or do the motions at Critical Points include the effects from all modes? 1/20
QA157 How fast is too fast? (when setting the SPEED parameter) 1/20
QA168 At what water depth can waves be considered "deep water"? 1/20
QA158 Why is the summary table at the end of the report? 12/18
QA159 What is variance? 12/18
QA160 How do I write RAOs to a data file? 12/18
QA161 What does "Undefined section normal at station..." mean? 12/18
QA162 What does "Unsupported geometry at station..." mean? 12/18
QA163 What does "Runaway mesh refinement" mean? 12/18
QA164 What is the peak enhancement factor (gamma)? (When using a JONSWAP spectrum) 12/18
QA165 What is the difference between the General, Narrow-band, and ITTC Bretschneider forms? 12/18
QA170 What are some considerations for predicting roll with Seakeeping? 09/23

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