CAD/CAM UPDATE In the second part of this special report, Partick Couser browses the host of new products available in the market
GHS – Creative Systems Inc
www.ghsport.com
sales@ghsport.com
Creative Systems, Inc, P O Box 1910, Port Townsend, WA 98368, USA. Tel: +1 360-385-6212. Fax: +1 360-385-6213.
G
HS (or General HydroStatics) is a very capable program that has been in development since
the early1980s. It is fundamentally command- driven, which lends itself to scripting (using ‘run files’) and this can add to the power of the program. A menu interface has been added and provides a more user-friendly interface than the command scripting language. Recently, a COM interface has been added, which allows GHS calculations to be scripted from other programs such as Microsoft Word and Excel. The capabilities of GHS can be extended with
a number of additional modules. For those on a smaller budget, the reduced capability BHS (Basic HydroStatics) is available. The majority of the additional GHS modules are also compatible with BHS. Like the majority of the software described in this
review, vessel (and tank/compartment) geometry is built up of components. Each component is made up by a number of transverse sections. A component may have either a positive or negative contribution
A menu interface has been added to the general hydrostatics programme which is more user- friendly.
to the vessel’s volume. Thus a bow-thruster can be ‘removed’ from the main hull by defining a bow thruster component of the appropriate geometry but making its contribution negative. Results are sent to a text file and this can be
read into Microsoft Word or Excel. Alternatively, the built-in report generator can be used. A fairly wide range of stability criteria calculations can be selected to define custom sets of stability criteria. Of the software reviewed, GHS is unique in being
able to analyse the interaction between multiple, independent floating bodies and in the ability to find and compute ‘GZ’ about the minimum
HST – Wolfson Unit offers user choice
www.wumtia.soton.ac.uk wumtia@soton.ac.uk
Wolfson Unit MTIA, University of
Southampton, Highfield, Southampton SO17 1BJ, UK.
Tel: +44 23 8058 5044. Fax: +44 23 8067 1532.
T
HE Wolfson Unit’s hydrostatic analysis program traces its heritage back to the early
1970s and has been in continuous development since then. The latest offering - HST- provides a full Windows graphical user interface, increased functionality, and improved algorithms. When combined with the Loading and Damage modules, HST becomes a comprehensive hydrostatic and stability analysis package, though it lacks some of the more complex analyses such as probabilistic damage and grounding. As with GHS, the hull and tanks are defined as
components made up of transverse sections. The user has the choice of using linear or parabolic integration for the section area and longitudinal volume integration. There are a number of tools to verify and correct any errors with the section data; this is particularly important when the parabolic integration method is used. The tree-control provides rapid navigation of the hull and tank geometry components. Tanks and compartments can be ‘carved’ to the hull geometry, which facilitates their definition.
THE NAVAL ARCHITECT FEBRUARY 2007
stability ‘heel’ axis – this can be especially useful for non-ship-like structures. It also provides IMO probabilistic damage analysis. Naval architects using GHS are able to easily
generate the necessary data for the GHS Load Monitor onboard stability system using a special GHS Load Monitor configuration wizard. The third-party software, Deadweight, (available
free) is able to produce 3D rendered images of the GHS model and is a useful visualisation tool. Documentation available with the demonstration
version was limited. A web-based FAQ is available.
Users of Wolfson unit's hydrostatic analysis have the choice of linear or parabolic integration.
Reports are generated in html format, which
can easily be pasted into Microsoft Word (with formatting). Graphs can be embedded in the report or plotted at specific scales if required by using the Wolfson Units GoPlot software. The use of hyperlinks facilitates navigation of lengthy reports. A fairly wide range of stability criteria calculations can be selected to define custom sets of stability
criteria. These are in addition to a number of standard criteria sets, such as the IMO HSC and IS codes. Naval architects using HST are able to generate
the necessary input data for the Wolfson Unit’s onboard loading and damage stability system, HST Onboard, using the HST Onboard Editor module. Documentation and online help are comprehensive.
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