RESPONSE

General description

RESPONSE is a PC based, interactive program for analysis of first order (6 degrees of freedom) response of floating vessels:

• Wave induced motion of any point on board:
  - motion displacement 
  - velocity
  - acceleration
• Specific seafastening forces (force per tonne mass of unit)

While the motion parameters are calculated in a fixed coordinate system, the specific seafastening force is presented in a coordinate system that rotates with the ship, so that the XY plane is always parallel to the deck (or more correctly: a vessel fixed plane which is horizontal when the vessel is on even keel, with zero heel angle). The Z axis is perpendicular to this plane. In the static case (no angular motion) this coordinate system and the fixed system coincide.

Input data

• Vessel motion characteristics (first order motion transfer functions), read from file.
• Sea state definition (spectrum parameters and directions for wind generated waves and swell). Irregular, wind-generated waves are modeled by a Pierson-Moskowitz or a Jonswap wave spectrum, while swell is modeled as a Gaussian spectrum. Long-crested (uni-directional) or short crested (direction distributed) waves may be specified.
• Water depth and ship speed

The influence of finite water depth and ship speed can be included in the calculation.
A limitation of the present version of the program is that the response calculation with a forward ship speed can only be made for long-crested waves and head seas +-90 deg.

Output

Standard deviations, significant amplitudes or expected extreme values are calculated and presented in tabular form. Plots can be produced by importing the output file to EXCEL or similar programs.

For further information, please contact Peter Chr. Sandvik