Virtual Marine Arsenal

PDStrip (Public Domain Strip) computes the seakeeping of ships and other floating bodies according to the strip method. Responses in regular waves are given as response amplitude operators.

PDStrip has been written in Fortran 90/95. It can handle unsymmetrical bodies including heeled ships. Forces on fins or sails can be taken into account.

The following responses are computed:

1. Translations in directions x,y,z of the ship-fixed coordinate origin.
2. Rotations around the three coordinate axes.
3. The translation of user-specified points on the body in 3 coordinate directions.
4. The relative translation between these points and the water assumed to be disturbed by the waves, but not by the ship.
5. The acceleration at these points; if required, after weighing with a function of motion frequency (encounter frequency)
6. The pressure at a specified number of points on each offset section.
7. Sectional force (3 components) and moment (3 components) in cross sections (x=constant) of the ship.

The program cannot deal with multi-hulls, air-cushioned vehicles or planing hulls. But PDStrip has several  special features making it suitable for practical applications to most ships and sailing yachts:

1. Consideration of discontinuous sections (as found at forebodies with bulbous bows)
2. Consideration of transom sterns.
3. Consideration of unsymmetrical cross sections (as in heeled ships)
4. Consideration of shallow or deep water.
5. Consideration of fins (such as rudders, bilge keels, etc.)
6. Consideration of active fins (such as roll stabilizers)
7. Consideration of roll damping due to sails in sailing yachts. With some precautions the method to take account of sails may also be applied to wind forces on superstructures of ships without sails or on deck containers etc.
8. Consideration of suspended loads (as in crane ships)