General HydroStatics
Ship Stability Software
Command of the Week
(New or interesting aspects of GHS that you may not know about)

SEA /BOX
(Requires GHS version 16.90 or later)

If you're using SEAKEEPING on box-like geometry (such as a barge or dock) and surge forces and responses are of interest, you should consider using the /BOX parameter.

What does the /BOX parameter do? It is a unique and convenient way to improve surge predictions on geometries with large, prismatic ends. Including the parameter tells SEAKEEPING to create a longitudinal "station" to compute the hydrodynamic surge forces while all other modes (sway, heave, roll, pitch, and yaw) remain the same.

In fact, /BOX works equally well with flat or raked ends. The only real stipulation is that the hull should have little to no transverse variation.

So should you use /BOX when you have a standard "curvy" hull? No. SEAKEEPING by default computes the three-dimensional normal vectors, so for most situations /BOX is not necessary. But if your ship looks like a box, use SEA /BOX.

Here's a surge RAO from a box barge of beam 70 ft, depth 23 ft, and length 300 ft analyzed using the /BOX parameter:



Questions, comments, or requests?
Contact Creative Systems, Inc.

support@ghsport.com

USA phone: 360-385-6212 Fax: 360-385-6213
Office hours: 7:00 am - 4:00 pm Pacific Time, Monday - Friday

Mailing address:
PO Box 1910
Port Townsend, WA 98368 USA

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