GHS
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GHS
Minimum hardware required: PI 133 (64 Mb for Win NT)
Operating system(s): Windows XP, Vista , 7
Most recent version date & number: October 2017, v15.88A
Number of installations:

1000+

 
GHS - General HydroStatics
BHS - Basic Hydrostatics
Additional modules
WMG - Windows Manager for GHS
GHS LM - GHS Load Master/Monitor
GHS Salvage


approval
Approvals & Certificates

 
  Description
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GHS is the most comprehensive (in absolute) and powerful (in the microcomputer world) stability calculator. GHS does not stop at calculating static stability parameters, but checks for positive stability in every condition and configuration.

GHS supports variable density cargo, staggered heel/flotation plane conditions (hopper dredges, barges, etc.) as well as any compartment damage combination. Longitudinal strength, floodable lengths, probabilistic damage, automatic class criteria checking, fully customizable output formatting (any language), etc., are only a few of the features found in GHS.
In addition, GHS offers a full depth programming language for the writing of macro routines, and linking to user-developed programs, thereby fully automating work to unrivaled heights. GHS includes several industry standard interfaces, and supports a large number of printers for the outputting of graphs and tables.

 
  Capabilities & New features
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  • Load condition graphics
  • Full and short versions of A-265 (VIII) probabilistic damage calculation
  • Ship torsional moment and torque
  • Bulkhead shear correction factor
  • Calibration of tank data from external sources (e.g. tank tables). Produces an "equivalent" model matching stability, hydrostatics, free surface and moment of inertia, content weight and centre of gravity, etc. (nb: "equivalent" models may not be suited for longitudinal strength calculation).
  • GHS-LM models only require tank tables (no more need for drawings as input)
  • SeaSafe hull interface
  • Transparent network printer support
  • Introduction of custom headers and footers in reports via user-defined text and bitmap files
  • Colour-printer support for graphs
  • Complex boom arrangements including multiple hook loads
  • HBL: hydrostatically balanced loading for tankers
  • Support of API forces and KN units
  • Support of external MAXVCG tables
  • Water-on-Deck calculations
  • Support of 2 shear force limits for hogging and sagging bending moments
  • Calculation of the Revised SDI for vessels 80-100 m (IMO regulation 25-3)
  • Several new print setting options
  • Introduction of the new variable DAMSTAT indicating whether any of the ship's tanks are damaged
  • Longitudinal Strength is computed both at specified frame locations (FRA) and at model section locations.

 
  Why Do You Need GHS ?
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GHS is an extraordinary computer software system which causes ordinary PCs to become powerful hydrostatics/ stability computing machines.

Developed by Creative Systems specifically for the PC and refined over a period of several years, GHS has become widely recognized as the most productive tool of its kind. It surpasses traditional mainframe-based systems such as SHCP both in capability and efficiency.

In constant use by major design firms and shipyards, GHS is well proven, reliable, and well accepted by regulatory agencies. GHS is truly general-purpose. Not only does it handle ship hulls, but also anything that floats or contains liquid - or both. It has been used to analyze and/or design submarines, SWATHs, dry docks, drilling platforms, 10-foot sailboats, 300-meter freighters, floating bridges, and even a floating golf course. When the going gets tough, GHS keeps going: churning out intermediate stages of flooding, simulating the spilling of cargo, and optimizing against complex stability criteria - automatically.

Since marine technology is not static, neither is GHS. In response to feedback from users and the increasing sophistication of stability standards, we're constantly extending and improving GHS to ensure its continued leadership and excellence.

GHS is simply the most efficient way to do common stability jobs, and the only way to do the hard ones. GHS is General HydroStatics.

Here is the fleet of software modules which compose the GHS system:

  • GHS : The main program - handles all of the stability computations.
  • AF : Advanced Features - includes IMO probabilistic damage.
  • CG : Condition Graphics - Illustrates the loaded condition of any vessel
  • FL : Floodable Lengths - mainly for preliminary design (GHS does "damstab").
  • GS : Grain Shift - calculates volumetric heeling moment for grain cargos.
  • HM : Hull Maker - makes certain hull models very quickly.
  • LE : Load Editor - a timesaver for working out loading conditions.
  • LS : Longitudinal Strength - shear, bending, stress, and deflection.
  • MB : Multi Body - Allows GHS to model the interactions of multiple vessels
  • MC : Model Converter - converts shapes from SHCP and HEC; to/from CAD, OFE and IDF files.
  • PI : Programming Interface - a procedure library to link program extensions directly into GHS.
  • PM : Part Maker - makes vessel models. You have to use it to believe it.
  • TS : Tank Soundings - special-purpose formats (GHS does soundings generally).

    While the most powerful installations include all of the GHS modules, we realize that some users do not require them all. Therefore, all modules except GHS, PM, and MC are optional.
    In addition, third party module: WMG
What Makes GHS Special?

There are a number of PC-based stability programs from which to choose. They all claim to do most of the same calculations GHS does; some cost more and a few cost a lot less. So what makes GHS so special - and more than worth its price?

Part of the answer lies in the special features. Automatic handling of the IMO "Severe Wind and Rolling" and "Probabilistic Damage" criteria, for example - a tremendous time saver. True CG shifts of tank contents both transversely and longitudinally for better realism and accuracy. Heeling about any axis (essential for some shapes - drilling units for example - and where longitudinal stability is a problem). And the unsurpassed ease of modeling complex structures and detailed interiors saves more man hours on a regular basis than perhaps anything else.

Part of the answer is certainly about efficiency - especially on the big jobs. Efficiency means doing a job accurately, correctly and on schedule. Computers naturally do things accurately, but whether a job is done correctly still depends on the person who prepares the inputs for the computer - and people are by nature prone to making mistakes. When mistakes have to be corrected, the schedule (and the profits) sometimes go out the window. But GHS helps a lot. First, with its macro commands it reduces the chances of human error by reducing input repetition. And secondly, when things have to be redone you can make a correction and rerun a complex report with very little extra effort.


A large part of why GHS is special has to do with its basic approach to the stability problem. Most programs follow a more-or-less traditional approach based on techniques developed before computers existed. But GHS is a wind from a new quarter. You won't notice the difference in a list of features - and you can even use it without noticing the difference (if you are thinking in the traditional way). But once you discover the direct, simulation-oriented approach which GHS encourages, you will never want to see another cross curve. (Of course, if someone insists on cross curves, you can get them from GHS.)

But there is something else in the "specialness" of GHS which we have trouble describing. Perhaps it's something intangible. People either grow fond of a computer program or grow to hate it. One shipyard architect said, "GHS is my right hand". An executive in a prominent design firm told us, "GHS is our life's blood". A man who helped design the original SHCP is reported to have said, "I can't face SHCP anymore - I've got to get GHS". After using GHS for about three years, a well known naval architect wrote, "GHS is absolutely stupendous in its completeness, versatility, and its accuracy". After using GHS in a research project, the project director wrote us a note saying, "I figure GHS saved us about two years of work". That's what makes GHS special.

 
  How Does GHS Work ?
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GHS (The Main Program)

You can do the ordinary things so easily with GHS that first-time users believe it's a simple program. But when they're still discovering features after a year or longer, they tend to have a different opinion.

Hydrostatics can be easy, but it can become involved and complex at times. GHS does not ignore the complexities of reality. It helps you think them through and solve the problems while recognizing the subtleties.

When you approach a hydrostatics analysis you have to make some decisions about how much detail there should be. You build a geometrical model of the vessel with the appropriate degree of detail. Then you run GHS with the model to simulate the vessel's resistance to heeling moments in various conditions - to an appropriate degree of detail. Preliminary designs can be modeled with less detail so that they can be quickly cycled through modification phases. Final designs will have more detail. The amount of detail which GHS handles is large, but not unlimited. With reasonable point densities, a hull including a dozen or so appendages, twohundred tanks and compartments, plus up to two hundred distinct non-liquid weight items is the limit.

How fast is GHS? It depends on how detailed your model is and what you want it to do. If you build a fancy model with a couple of hundred tanks and set it up to find maximum VCG in a dozen loading conditions, each multiplied by a number of damage scenarios with intermediate stages of flooding, you will need to be prepared to do something else while GHS is crunching numbers.


But if you just want a righting arm curve from an average model, it will take less than a minute (much less on a fast computer).

Damage stability is straightforward with GHS; and what happens with loaded or empty tanks with and without damage is all taken care of automatically. True CG shifts in tanks are the norm (the traditional but less-accurate free surface "correction" is optional).

Heeling moments from the wind plane and other sources are available, as are several kinds of waves. GHS does almost everything with few restrictions - heel and trim are unlimited, for example (great for salvage work). You can even change the heeling axis - heel on a diagonal or even do a fore-and-aft righting arm curve.

Stability criteria are built in but not cast in concrete. You can choose your own limits and roll your own combinations. Tell GHS your criteria and it will find the maximum VCG - even with damage, wind or wave, or all three together.

No description of this program would be complete without a mention of the macro facility. Being command-oriented (vs. menu-oriented, although menus can be used), GHS is actually a language in which you express the design of the report you want to create - using the terms of your own building blocks, which are called "macro commands". It's the lever with which you can easily move a mountain of data.
GHS Plots

Pictures in a printed report are helpful. The GHS report generator takes the entire output stream, inserts the graphics, and puts the entire report out on the printer - all automatically. This operation is almost invisible because the program makes all of its decisions automatically. The only decision you have to make is whether you want graphs in your report. If you do, then the report generator does the job with no questions asked. The report generating facility in GHS is actually a complex piece of software, in spite of its apparent simplicity; and a close examination of the output it produces proves the point.

GHS produces all of its output by means of ordinary pin, inkjet, and laser printers on standard 8.5" wide paper. We have made no attempt to support pen plotters because doing so seems to be contrary to some of the philosophy behind GHS. This may take a bit of explanation:

We believe that the proper goal in designing software is to direct the resources of the computer toward accomplishing the whole task, not just to mechanize a step in the process. In the case at hand, we looked at the traditional production and use of plotted hydrostatic data and decided not to support the production of large-format plots.



We realized that while it helps the understanding of a process or trend to see the relevant data in a graphical form, there is seldom a need to actually use the graph as a source of data for working out a problem, since GHS on a personal computer can solve the problem directly. The plots available from GHS using either a 24-pin dot matrix printer, a high resolution inkjet, or a laser printer are about as precise as those made with a pen plotter; and they can be read accurately enough to be as useful as those drawn on larger-sized paper. They're also much easier to handle. Currently, GHS produces the following kinds of graphs:

  • Hydrostatic Properties
  • Maximum VCG Curves
  • Curves of Form
  • Longitudinal Strength Curves
  • Sectional Area Curves
  • GM vs. Tank Loading Curves
  • Cross Curves of Stability
  • Tank Soundings and Characteristics
  • Righting Arm and Area Curves
GHS Extensibility

By extensible we mean that GHS provides facilities for its own extension and expansion. It gives you the ability to create new features and procedures. This extensibility is of four major kinds:

1) Macro Commands. A macro command is a new command which you design yourself. The concept is that you can encapsulate your own procedures so that they become part of your "customized GHS". This is an extremely powerful and easily-used feature.

2) Menu Systems. You can design and create various menu-driven "applications" within GHS. A MENU command is provided which, together with macro commands, allows you to create programs for specific applications which can then be used by someone with little or no knowledge of GHS.


3) Programming Interface. Virtually any conceivable feature or calculation can be added to GHS with this facility. It allows you to integrate your own programs into the GHS environment while giving you access to the underlying data and "hydrostatics engine".

4) File Interfaces. Several kinds of "industry-standard" data files are recognized by GHS. This facilitates communication between GHS and other programs so that you can assemble a system of software extending into areas not covered by GHS.

Extensibility means that you are not locked into one way of doing things. It also increases your options for enhancing and developing GHS to meet specific requirements.
Part Maker

In order to understand Part Maker, you need to understand that in GHS we literally build a model of the vessel, and base all calculations on the model - not on intermediate abstractions such as Bonjean Curves. This is true not just of the hull(s) but also of the tanks, compartments, appendages - everything which contributes to the buoyancy or windage.

Of course, we are speaking of a mathematical model comprised of numbers; but the effect is very much like that of a physical model. You can view the model from various angles and manipulate its individual Parts.

What is a Part? Just those things which you want to handle when doing stability work. Each tank, for example, would be a Part; and obviously the hull would be a Part. Normally, the hulls of a multi-hull vessel would all be put into one Part, since there is usually no need to see their separate hydrostatic properties. But a ship in a dry dock would typically be a separate Part from the dry dock hull.

Still, Parts can be quite complex - such as a hull with several appendages. So GHS allows you to build your Parts from pieces called Components.

Take the case of a thruster tunnel. It not only modifies the hull, being a "negative appendage", but it probably modifies one or more tanks also. If you have ever manually constructed stations in the way of a thruster tunnel because the tunnel indentation had to be integral with the hull shape, you will love Part Maker.


It not only constructs the cylindrical tunnel with one simple command but it fits the tunnel to the hull and will even fit tanks around the tunnel!

In short, Components allow you to build complex Parts accurately and quickly without causing unnecessary detail to clutter the reports.

Part Maker is a solid modeling tool designed specifically for hydrostatics models. It makes tanks, compartments, appendages, sponsons, camber, shell, insulation and fits them all together. It can scale, shift, stretch, combine, and display models.

Part Maker essentially extends the GHS command language so that the construction of a model can be described. Just as important as the final model itself is your expression of how you build the model; and this you can preserve for future reference. We call it the Run File. If you want to change the model in any way, simply edit your Run File and run Part Maker again.

Because it gives you so much power, we consider Part Maker to be an essential part of GHS. Rowing is fine if you have the time. But if you want to get there fast, you need a motor and you need Part Maker.
 
  GHSCOM
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GHSCOM provides access to the GHS (General HydroStatics) main calculating engine through Microsoft COM technologies. This allows GHS to be tightly integrated into other programs. Any application written in a language that supports the COM calling convention can link to GHS through the GHSCOM module. Such languages are,

• C/C++
• C#
• Delphi
• Java (COM Bridge)
• Visual Basic
• Visual Basic for Applications (VBA)
• VB Script

VBA is of particular interest since common application programs support VBA including Microsoft Office and AutoCAD. This means that a GHS user can write VBA functions in Excel, for example, and with very little effort have a spreadsheet with cells that call GHS functions.
GHSCOM is an optional module of GHS and cannot be used independently of a GHS license.

The GHSCOM interface is simple. It provides for sending commands to GHS and for retrieving variable values. Standard GHS file output resulting from the execution of commands can also be produced. No screen window for input or output is provided since those functions are to be supplied in the user's host program. This precludes the use of Load Editor and any other GHS commands that require screen output or take keyboard input.

Other commands not available through GHSCOM are those having to do with general file handling and execution control -- things that are easily done in the language of the host program.

 
  Additional Modules
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Advanced Features
The Advanced Features (AF) module adds certain tools to GHS which are very useful for certain kinds of vessels but are not needed by all GHS users.In its present version the AF module contains two tools; one for intact stability, the other for damage stability.

- Intact Stability
Addressing a special problem which occurs with submarines, floating drydocks, and other submersible structures, a table and plot of transverse GM as a function of tank loading is produced. This makes it easy to spot low GM phases in a submerging or emerging operation.

- Damage Stability
Our implementation of the IMO probabilistic damage evaluation for cargo and RO-RO passenger vessels is also provided in the AF module. This is a complex rule which assigns probabilities to various extents of damage and probabilities of survival related to the stability characteristics in damaged conditions. A summation of these probabilities over all survivable extents of damage yields a "Subdivision Index" which is compared to a minimum requirement for the particular vessel.
Functionally, the AF module is smoothly integrated with the GHS main program so that they appear as one program.

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Condition Graphic
Enhances reports from GHS
Features

  • Illustrates the loading condition of any vessel
  • Accurately pictures tank levels
  • Shows the waterline at actual drafts
  • Shows the ship rotated to actual heel and trim
  • Both on-screen and printed renditions
  • Color and black-and-white printouts
  • Simple activation through the DISPLAY STATUS command
  • Selectable views and cut locations: plan, profile and body
  • Reversible profile view to clearly show tanks on both sides
  • Includes the standard GHS header
  • Optional custom footer includes user's logo

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Floodable Lengths
FL does the traditional floodable length calculations, based on symmetrical flooding and sinkage to a margin line or to a condition of minimum GM. It presents floodable length data at regular intervals along the length of the vessel, including not only the length of flooding but also the trim, sinkage, margin, and GM.

This is a preliminary-design tool, since it does not use any actual compartment boundaries which may be in the vessel model, but rather "designs" its own simple compartments which are as large as they can be to satisfy the margin line and GM requirements.

Given the ease of modeling and modifying compartments using Part Maker, it is quite possible to do a better job of preliminary design using damage stability (with GHS), especially when the assumptions of uniform symmetrical flooding and the simplistic stability criteria of FL are not valid. But floodable lengths are still useful ... and they are sometimes required.

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Grain Shift
The Grain Shift (GS) program calculates volume, volumetric heeling moment, and vertical center of gravity as a function of ullage. It works well for any tank, but is especially applicable to grain holds.

Grain cargo is neither perfectly solid nor liquid. If a hold is not completely full, the surface of the grain can shift and remain inclined toward one side in response to the rolling of the ship, resulting is a somewhat permanent transverse and vertical shift of the center of gravity.

GS is especially equipped to account for the various structural complexities sometimes found in grain holds which obstruct the surface of the grain. Void pockets are modeled as components of the hold. As the cargo shifts within a pocket some of its void may escape to another pocket.

Grain Shift produces screen and printer plots of volume, volumetric heeling moment, and VCG as a function of ullage.

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Hull Maker
The concept behind this module is that a suitable approximation to a hull form can, in many cases, be generated from very little input data. For example, the principal dimensions, type of ship, and a few particulars about sheer, deadrise, bulge radius, etc. are enough to specify the mid sections. With some additional information about the ends, a hull model can be generated without actually giving any offsets.

In its present form, Hull Maker is restricted to barge shapes and is actually more commonly known as "BARGE". It is capable of modeling some barges exactly and almost all barges fairly closely. Once a barge hull is created, Part Maker can be used to augment it, adding appendages and superstructure if necessary.

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Load Editor
Load Editor is an interactive interface through which you can quickly access certain commonly-used GHS features. For example, with a single keystroke you can change the loading of a tank and instantly observe the result of the change relative to a specific set of stability criteria.

Load Editor has two applications. One is the design evaluation of a vessel's stability, where various loading combinations are being investigated to determine maximum cargo loading or to explore dangerous combinations of partial loads. The other application is in the actual operation of a vessel to monitor the stability and strength margins related to a loaded condition (see GHS LM).

The Load Editor screen resembles a spreadsheet where each load item is represented by a line on the screen. Pressing the arrow keys moves the visible marker about on the screen, thus enabling you to point to any item and make changes. Loads can be entered as percentage full; volume or sounding; or by actual weight or percentage present for non-liquid loads.

The top of the screen is dedicated to showing the vessel's drafts, trim, displacement, overall CG, GM, maximum VCG, and VCG margin which change instantly in response to the operators inputs. The bottom of the screen shows profile and plan views of the vessel with tank boundaries and weight locations. Longitudinal bending stress and deflection are computed by pressing a key which temporarily brings in the LS module. The deflection so computed can even be retained and reflected in the draft readings.

Whether in the architect's office or on board a vessel, Load Editor is an efficient and accurate tool for working out the stability and strength margins.

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Longitudinal Strength
If you dislike the drudgery of assembling a weight curve for longitudinal bending, you will appreciate LS. It does the assembling for you. Give it weight density information in pieces and it produces the composite weight curve automatically. The pieces you give it need not be constant, they can vary as a function of length; or they can be concentrated at a point. Even more helpful, LS automatically adds in the weight density curves for tank loads.

If you supply section modulus, you get stress; or if you just give section moments of inertia you can still get deflection.

LS produces and presents the detailed strength curves along with a summary showing maximum values and locations. You also get fine-looking and serviceable plots of the curves.

Of course, LS works with waves and with damage. It is not restricted to upright conditions - for those situations where bending in other directions is important.

Where deflection is important, LS can be used, with suitable calibration, to predict deflection so that the resulting drafts and hydrostatic properties can be examined with the hog or sag.

In spite of all its rigor, LS usually takes just a few seconds to produce an answer. And being tightly integrated with GHS, it is quite easy to use.

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Model Converter
MC converts geometry data to the GHS Geometry File format from various other formats and vice versa. Currently it does the following conversions:
SHCP and HEC hull and tank definitions to GHS Geometry
CAD drawings (DXF) to and from GHS Geometry
Offset (OFE) files to and from GHS Geometry
IMSA Data Files (IDF) to and from GHS Geometry
PIAS (EAG) offsets to and from GHS Geometry

SHCP Conversions
Since there is a significant difference in the way in which SHCP and GHS interpret offsets, MC reads and processes the SHCP data in the same manner in which SHCP does. However, MC does a much more thorough job of checking the SHCP offsets for errors than SHCP does itself. Many of these errors, if undetected, can lead to serious errors in SHCP calculations. So we would say that even if you are using SHCP you need MC to check for errors!

Compared to the SHCP method of representing hull geometry, GHS uses a simpler representation which is more reliable and more suitable for automatic computation. (SHCP bases its representation on the requirements of Simpson's first rule for area integration.) However, the GHS representation (based on the requirements of trapezoidal integration) requires roughly twice as many points and stations to achieve a comparable level of precision. MC adds these points and stations automatically.

One interesting feature of the SHCP-to-GHS conversion is that longitudinal and transverse aberrations (due to incorrect station spacing in the SHCP model) become visible after the conversion. Even when the SHCP model is considered "clean" because no transverse "blips" are present, there may be "longitudinal blips" which would appear in the area curve only at certain waterplane orientations and would therefore be difficult to detect. The GHS form of representation avoids this problem, since all area curves are closely related to the model as it appears by inspection.

DXF Conversions
MC will read and write DXF files (2D or 3D). This allows a shape to be created in a CAD program (including digitizing from an existing body plan) and then converted into a Geometry File for use within GHS. It also allows stations from a Geometry File to be copied into a CAD drawing.

OFE and PIAS Conversions
The OFE file format is used by some hull design systems as a means of exchanging shape data between programs. MC will both read and write OFE files. The PIAS EAG format is a simple offset list.

IDF Conversions
The IDF file format is described as "a neutral file format for exchange of hull description data between marine programs". MC converts the "SECTION" entity which describes the hull in terms of sectional curves. MC will both read and write IDF files.

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Multi-Body
The Multi-body module allows General HydroStatics (GHS) and GHS LM (GHS Load Monitor) software to handle multiple floating bodies with points of contact between them. Ground contact can be included simultaneously.

> Applications include:
-onboard load monitor for tug-barge units;
-detailed simulation of loading and unloading floating objects by partially submerging the carrier:
- complex salvage procedure modeling;
- ice breaker simulation;
- dry docking;
- articulated floating structures.

Equilibrium of the entire multi-body system is found automatically and the forces at the points of contact are reported.

This new capability is available through an optional software module being called simply "Multi-Body" or MB. It is tightly integrated with GHS so that the usual features of the program can be used in conjunction with it.

The MB module allows GHS to model the interactions of multiple vessels in a wide variety of configurations when latched together or resting on each other. It models each vessel in a separate side-by-side session of GHS and quickly solves for simultaneous equilibrium whenever anything in the system changes. For example, the effect of changing the load in a tank on one vessel can be seen also in the draft, trim and heel of the vessel with which it is in contact as well as in the contact force. The contact forces are automatically included in stability, longitudinal strength and torque calculations.

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Programming Interface
The GHS Programming Interface (PI) consists of a procedure library to which the user can link his own programs. This allows you unlimited freedom in developing your own extensions to GHS.

A command called "CUSTOM" is the gateway through which user-written commands are integrated with the GHS environment. Thus one or more special commands can be added to the system to do things which are presently outside its scope, or to change the way in which things are presently done.

The Programming Interface consists of a library linkable to programs written in specific programming languages. It includes over 50 procedures covering access to the geometry data and various calculations.

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Surface Areas
The purpose of SA is to calculate hull and deck surface areas and centers of gravity. This is not the same as wetted surface (which is provided in the Main Program) but rather it takes the entire area of the hull component up to the deck edge and provides not only the area but the center of the surface, making it useful for weight estimates. At present, the SA module is in a very preliminary form. It is being made available to GHS users "as is" without additional charge.

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Tank Soundings
Tank sounding tables are interesting because of the variety of formats and requirements which are encountered. Since some of those requirements are quite specific, we made a special module to handle them.

GHS also produces tank sounding tables with a considerable amount of flexibility in the makeup of the table. While the tank tables from the GHS main program are intended primarily for design work, the TS module produces sounding tables for use in the field. TS offers five table formats:

1) Gallons vs. Sounding in inches, arranged in vertical columns;
2) Gallons vs. Sounding in feet and inches, arranged in a 12-column table;
3) Gallons, Cubic Feet, Center of Buoyancy, Moments of Inertia vs. Sounding in feet;
4) Same as 3 except a Trim Correction column replaces the Longitudinal Moment of Inertia;


5) Cubic Feet, Gallons and Long Tons vs. Sounding and Ullage in feet and inches.
Either U.S. or Imperial gallons may be selected for any of the formats. None of these formats allow metric units.
Formats 1 and 2 are more compact than any of the formats available in GHS and are therefore especially attractive for use in the field if only volumes are needed.

Formats 2, 3, and 4 meet specific US Navy requirements. Formats 3 and 4 include special interpolations at breakpoints.

Format 5 shows both sounding and ullage simultaneously.

We expect that eventually, computers will be so accessible, reliable, and common that tank sounding tables on paper will cease to be produced. Until that happens we can add new formats to the TS program to meet any special needs.

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  GHS Salvage
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Because it is fundamentally simulation-oriented, GHS is an excellent tool for answering the "what if" questions involved in salvage operations. And since it does not limit trim and heel angles, you can simulate any orientation in which you might find a distressed vessel - from upright to upside down to standing on end.

Several other features are also of special interest to the salvage engineer:

Quick model generation
GHS provides a means of very rapidly constructing a hull model from a small amount of information. Even rough dimensions together with a general knowledge of the hull form are sufficient to produce a useful model. Weight estimates can then be obtained from the operating drafts. The ability to import hull models expressed in various data formats is also provided.

Damage simulation
Damage limited by compartmentalization and damage in the form of hull deformations are readily simulated. Both types of damage can be present together and both can be nonsymmetrical. three modes of tank damage are provided, including pressure balancing for accurate oil outfolw calculations.

Partial flooding
Since GHS computes the weights and centers of all contained fluids at any given vessel orientation, partially flooded spaces are accurately represented.

Ground reaction calculation
The locations and magnitudes of the forces exerted by the ground when a vessel is stranded is easily determined. GHS provides a very flexible and realistic ground reaction mechanism.
Stability and stress when damaged and grounded
Damaged, flooded and groundedstability, and longitudinal strength calculations are easily and quickly obtained.

Downflooding and spilling
Downflooding points can be modeled and their heights above or below the water are readily obtained. Spilling of water on deck from a tank can also be calculated.

Sealed and vented tanks
Tanks may be pressure-balanced at the point of damage, with vented or sealed tops. This allows accurate calculations of cargo loss when damaged.

Complex models
Situations where a ship is combined with a dry dock or is being loaded onto a barge are easily modeled. Other complex structures such as floating drilling units and various pontoon structures are also readily handled.

Menu systems
In order to simplify the use of GHS in the field, menu systems can be built which directly address the various requirements of salvage work. A standard salvage-oriented menu system is provided.

Extensibility
Because GHS is general and extensible, other salvage-specific features can be added by building onto its basic facilities. The ability to make such additions is available to the user.

 
  What is BHS? 
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BHS is similar in many ways to GHS, being a derivative or "subset" of the larger program. BHS includes hydrostatic properties, curves of form, cross curves of stability, load condition status, heeling and trimming moments, wind heeling derivation, righting arm curves and areas (with constant trim or constant trim moment), tank characteristics and soundings, damage stability, stability on waves, intermediate stages of flooding, tank CG shifts, and much more. BHS produces high-quality reports with graphs and has the same wide recognition and acceptance as GHS. On the model-building side of the system, BHS comes with Section Editor - the graphical hull modeling tool - and a version of Part Maker which makes it easy to build all sorts of tanks and compartments into the model. Most of the GHS optional modules are also available with BHS.
These are Model Converter, Longitudinal Strength, Load Editor, Floodable Lengths, Tank Soundings, Grain Shift, and Hull Maker. What BHS lacks relative to GHS are, most noticeably, some of the features from Part Maker which help with the creation of appendages (but appendages can also be created using Section Editor); it also omits the automatic stability criterion evaluation facilities of GHS; the maximum-VCG solving; BHS cannot change the axis of heel; it lacks the tonnage calculation; and it does not have access to the Advanced Features or the Programming Interface modules. Since BHS includes most of the features of GHS, its price makes it a great value. It also retains its value because it can be traded in with credit for its full purchase price for an upgrade to GHS.


 
  WMG
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Visual Systems Workshop began developing software for the naval architectural community in 1995.

"GHS" has been the personal computer stability standard since its introduction about 25 years ago, by virtue of its rich feature set and unrivalled power. Although most GHS components are in fact 32 bit native Windows® programs, the user interface does not include a pull-down menu. WMG4 adds Windows standard features to some of GHS modules (pull-down menus, etc.), and completely replaces others with user-friendly Windows® programs.

The WMG - Windows Software Library modules are:

 GHS Enhancer (v4.0) (not upgraded in WMG v5.0)

General HydroStatics (GHS) is a general purpose 16 bit DOS or 32 bit Windows stability program developed and licensed by Creative Systems, Inc.. GHS has become the personal computer stability standard since its introduction in 1984, by virtue of its rich feature set and unrivaled power. Both versions of GHS use the command entry style of interface, similar to old DOS commands. The reason for this approach is that it allows a far larger command set than can be implemented in a menu interface.

There are, however, a significant number of frequently used command combinations. GHS Enhancer (GHSE) is an interface that adds menu functionality and other enhancements to the General HydroStatics (GHS), Basic HydroStatics (BHS), and Basic Hydrostatics Yacht (BHSY) programs by Creative Systems Inc. when operating in the following environments:

  • DOS GHS/BHS/BHSY under Windows 98/ME
  • Windows GHS/BHS/BHSY under Windows 98/ME/NT4/2000/XP

Beginning with the 32 bit version of GHS v7.50, Creative Systems added a rudimentary set of native menus. On versions before 7.50, GHS Enhancer adds a standard menu bar to the window. After version 7.50, GHS Enhancer augments the existing menu bar with additional menus. GHS Enhancer v4.0.08 or later is required for use with 32 bit GHS v7.50 or later.

GHS Enhancer also solves a long-standing problem with running GHS in Windows - setting the current directory. When launching GHS Enhancer, you will first be prompted to select the working folder, which defaults to the last folder accessed by any of the WMG components. The current folder name is then inserted into the new window's title bar, so you always know where you areey assignments and macro names are placed in customizable menus.
In GHS Enhancer, both menus and typed commands are supported. The most commonly used commands are contained in menus, and any other commands may be typed into the GHS window, or run from standard run files. When running files from GHS Enhancer's file menu, macro names and function key assignments are automatically placed into menus.
In addition to GHS Enhancer's other features, it also provides direct access to GHS's on line help library, and includes searching features not available anywhere else.

GHS Enhancer remains at version 4.0 (no version 5.0 is available). This program will be gradually phased out as Creative Systems (the developers of GHS/BHS/BHSY) completes its conversion to a full 32 bit Windows program with useful menus. Existing users of version 4.0 do not need to purchase upgrades.

 Part Maker Enhancer (v4.0) (not upgraded in WMG v5.0)

PartMaker Enhancer (PME) is an interface that adds menu functionality and other enhancements to the Part Maker program by Creative Systems Inc. when operating in the following environments:

  • DOS Part Maker under Windows 98/ME
  • Windows Part Maker under Windows 98/ME/NT4/2000/XP (PartMaker for Windows is under development by Creative Systems)

The Part Maker program lacks the menu driven interface which makes using Windows programs so much easier. PartMaker Enhancer extends Part Maker with the addition of menus and other dialogs, which makes it much easier to use.
In PartMaker Enhancer, both menus and typed commands are supported. The most commonly used commands are contained in menus, and any other commands may be typed into the Part Maker window, or run from standard run files.

In addition to PartMaker Enhancer's other features, it also provides direct access to Part Maker's on line help library, and includes searching features not available anywhere else.

PartMaker Enhancer remains at version 4.0 (no version 5.0 is available). This program will be gradually phased out as Creative Systems (the developers of PartMaker) completes its conversion to a full 32 bit Windows program with useful menus. Existing users of version 4.0 do not need to purchase upgrades.

 Chart Virtuoso (v5.0)

The Chart Virtuoso module displays, edits, and prints GHS graphics (.PF/.GRP) files, such as Maximum VCG curves, Righting Arms, etc.. Its capabilities include options for selecting the principal axis data & orientation, and showing or hiding curves. It can even merge different plots together!

  • Reads & displays GHS™ generated charts (both text and chart pages).
  • Select the data set you want to use for the principal axis, and its direction.
  • Select the data set (curves) you want to display.
  • Individually re-scale the displayed curves.
  • Export charts in AutoCAD™ DXF format.
  • Export charts in Rich Text Format (RTF), readable by most word processing programs.
  • Copy charts to the clipboard.
  • Save your customizations to file.
  • Select the fonts, display format, margins, colors, and page orientation.
  • Merge maximum VCG curve sets.
  • Edit text pages. (new!)
  • Edit graphics page commands. (new!)
  • Edit graphics page curve data. (new!)
  • Insert additional text pages. (new!)
  • Delete individual pages. (new!)
     

 

One of the great benefits afforded by Chart Virtuoso is the ability to generate reports completely within your computer with its export features. In combination with word processing or page layout programs, an entire report can be assembled in a single computer file. Contrast that with the typical piles of printouts!

 Geometry File Modeler (v5.0)

The Geometry File Modeler creates, displays, and edits geometry files. The GHS modeling system uses a hierarchical system of "parts", "components", and "shapes". Parts are composed of one or more components. For example, the HULL part may be composed of the basic hull component, a skeg component, a bulb component, and a deducting bow thruster component. Components are pointers to shapes, and provide information on the side, effectiveness, and reference point. Shapes contains the basic coordinate geometry. A single shape may be referenced by several components. For example, a sump's shape may be used as a component of a wet hold, and also a deducting component from the tank underneath.

A typical display is shown below, showing the standard three views (profile, plan & axonometric) in resizable panes. Each view pane may be zoomed independently. A drop list of model parts is presented in the upper left corner. Next to that is the components drop list, which contains the components of the currently displayed part. The Render menu allows visualization of 3-dimensional part surfaces, as shown in the example below. Other buttons control part, component, and shape editors, part & component selection, rotation (360 degrees both horizontally and vertically), section selection, and point selection.

 

Main features include:
  • Multiple documents interface can open several geometry files & shape editor sessions simultaneously.
  • Manipulate all geometry file model data without using a text editor.
  • Import and export shape geometry using OFE or OF4 file formats.
  • Export AutoCAD(R) DXF files in 2-D or 3-D format.
  • Use the Part Editor to copy components from part to part.
  • Use the Component Editor to change a component's shape assignment
  • Use the 3-D Shape Editor to enter & modify coordinate data, and cut waterlines & buttock lines.
  • Copy images of your models to the clipboard for pasting into documents.
  • Colors may be user defined, or the standard white or black backgrounds schemes may be used.
  • Automatically remove excess coordinate data to increase GHS computation speed.
  • Cut buttocks and waterlines into shapes.
  • Add parallel mid-body plugs with keel drag.
  • Scale & shift your model in any direction, which is helpful in the early design stage when vessel dimensions are being determined.
  • Render your geometry file in stunning 3-D for a realistic view of your model.
  • Reorder your parts and components. (new in v5.0)
  • Mirror sections about a shape's centerline automatically.(new in v5.0)
  • Reverse section point order (sometimes an imported file will have points in the wrong order). - (new in v5.0)
  • Rotate sections about a longitudinal line. (new in v5.0)
  • Digitize sections from an image file. (new in v5.0)


 EditX (v5.0)

EditX is a text editor primarily used for creating and editing text command files for use with scientific applications. It is similar in functionality to Microsoft's® NotePad™ that comes with Windows, except that it can display multiple files simultaneously.

In addition to the standard editing features, EditX allows you to turn off or on word wrapping, and allows you to specify which file extensions your want to associate with EditX. For example, you could associate the ".run" file extension with EditX, so that your can open all ".run" files with EditX from Windows Explorer.

New in version 5.0 is a button bar of open documents, and optional printing of page headers showing the file name and page numbers.

And the best part... Its free with the purchase of any other WMG module!


 Midship Section Calculator (v5.0)

Midship Section Calculator (MSC) calculates sectional properties of ship cross sections in a CAD-like environment. Why calculate section properties with spreadsheets, which leave you guessing if you included everything? MSC's graphic interface continually shows you what you have included. If you are performing ship design or salvage tasks, MSC is the tool you need!

Although primarily intended as a tool for calculating properties of large composite sections, MSC can also be used to calculate simple beam & plate combinations. With the capability to rotate sections, unusual beam combinations can also be evaluated.


Features of Midship Section Calculator include:
  • Structural shape library.
  • Structural shape building tools.
  • Structural shape rotation, mirroring, and snapping to plates.
  • Plates are defined by their endpoints, thickness, and molded line convention.
  • A plate sequencing tool for entering a sequence of plates.
  • Plate importing from GHS geometry files. (new in v5.0)
  • Plates can be optionally snapped to other plate's endpoints or sides.
  • Construction tools make it easy to copy, array, and mirror shape and plate elements.
  • Change the units on the fly between inches, feet, millimeters, centimeters, or meters.
  • Optional snap grid. (new in v5.0)
  • Optional overall centroid display. (new in v5.0)
  • Export models to AutoCAD DXF files. (new in v5.0)
  • Optionally save calculations to tab delimited text files. (new in v5.0)

 Extractor (v5.0)

Many programs produce extensive amounts of text output, which repeats in an organized manner. Extractor is used for extracting tabular data from such text output files, using user-defined search parameters. Extracted data can then be moved to a spreadsheet type program for further analysis.

Some Spreadsheet type programs can read text files, and even organize the data into cells. In many cases this is much more than you want. With Extractor, you specify which specific data you want, and ignore the rest. For example, consider the following text output from a vessel stability program:

Using Extractor, you could easily extract a spreadsheet table such as this:

Draft

Trim

Displacement

GMT

11.819

Fwd 0.52

448.83

9.70

11.182

Fwd 0.60

394.44

10.08

Extractor's key features include:

  • A simple interface.
  • Optional set divider and configuration panes in main interface. (new in v5.0)
  • Configuration wizards.
  • Data sorting.
  • Data charting via file output in Chart Virtuoso format.
  • Edit extracted data in cells. (new in v5.0)
  • Column reordering. (new in v5.0)

You define what data you want extracted by specifying key words to look for (such as "Total Weight"), the row and column offset from the key word to the extraction text, and the number of characters to extract. You may also have Extractor search for the start of the nearest word to the extraction position, for the case when the column offset is not constant. To extract entire tables, the Row Count may be set greater than 1. The Configuration Wizard allows you to preview the file you will be extracting from, and simply select a sample Search Text and sample Extraction Text.

 Panel Weight Estimator (v5.0)

Panel Weight Estimator (PWE) enables you to quickly generate a steel, aluminum, fiberglass, or wood weight estimate of hull structure using a panel approach. PWE is not a detail type weight estimating program, where you account for every individual stiffener. Instead, PWE lets you assemble triangular panels in groups, and assign unit weights to the panels (such as pounds per square foot or kilograms per square meter). The unit weight includes panel stiffeners and girders! A built in tool helps you determine the unit weight, and assign it to panels.

To start the process, you should have a hull defined in Creative Systems's geometry file format, or in Multisurf's OFE or OF4 formats. A companion program to PWE called Geometry File Modeler may also be used for this purpose. This is then imported into PWE, which converts the sectional data into triangular surface panels. You then organize the imported panels into groups, and assign panel weights. Any standard units of measure may be used, both English and Metric. Additional panels can then be added, fitted to existing panels.

Once you have created your model, you can:

  • Calculate & save weights and centers.
  • Calculate the weight distribution, & save to a Chart Virtuoso file, tab delimited text file, or GHS command file. Weight curve simplification is optional.
  • Calculate & save areas for painting.
  • Export the 3-D panel model to AutoCAD via the DXF file format.

PWE version 5.0 has been updated with the following improvements:

  • Panel selection handles have been removed (now select anywhere inside panels).
  • Added manual outline entering for automatic panel filling.
  • Updated display to use Microsoft's fast DirectX 8 rendering engine.
  • Both Wire-frame and Rendered view modes available (rendering is no longer a temporary display).

A typical display is shown below, showing a rendered sample weight model. The shell panel groups have been turned off to allow viewing of the inside of the model.

In order to quickly assign panel unit weights, PWE includes a Unit Weight Estimator as shown below:

How accurate is Panel Weight Estimator is a frequent question. The answer rests with you, as the model builder. The more accurate you are with panel unit weight assignments, the better your results will be. The technique used by PWE was used to calculate the steel weight of a passenger ferry, and the results were practically identical to the shipyard's full steel weight takeoff. If you want a very good steel weight estimate in a relatively little amount of time, PWE is the program you need.

 System Requirements

The following hardware and software is needed to run WMG version 5:

  • Windows 98, Windows ME, Windows NT 4.0 (Service Pack 4), Windows 2000, Windows XP
  • 16 megabytes of Random Access Memory (RAM) in addition to operating system requirements.
  • Pentium or higher CPU (Pentium III or later recommended) .
  • Familiarity with the Windows operating system and the GHS system.
  • Microsoft DirectX 8 or later (for rendering in Geometry File Modeler and Panel Weight Estimator)
  • Video display adapter with hardware abstraction layer (HAL) support (for rendering functions).
  • Recommended: Creative Systems modules "GHS" v6.18 or later (16 or 32 bit), and "PartMaker" v2.20 or later .


Where GHS & PartMaker version numbers are noted above, Creative Systems has upgraded their programs to allow interfacing with WMG, or WMG was modified to reflect revised command syntax. Later versions are also supported.

We no longer claim support the Windows 95 operating system. If you have Windows 95 and are interested in purchasing WMG, we recommend that you download (6462 ko) the demonstration version first, and test it out on your system. International Settings :
The Windows Control Panel's "Regional Settings" allows setting the numeric format. WMG version 5.0 allows the user to enter data using the control panel's numeric style, or U.S. decimal period style. Numeric display output is always consistent with the control panel's numeric style setting.

 
 
  Latest updates / patches 
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These GHS updates apply onlY to GHS v15.00 or later:
please contact us at ndar@ndar.com for the current GHS download location.
 
Read the GHS 15.88A Release Notes
Download GHS 15.88A
Download GHS auxiliary program - 15.88A

Download GHS PM

Download GHS DAMSTAB


Link to Creative Systems (GHS)

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