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

(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:

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