SeaKeeping

The GHS SeaKeeping Optional Module is based upon a linear, 6-degree-of-freedom, rigid-body, frequency-domain, strip-theory method with variable heading and forward speed terms. The module is fully integrated with GHS, meaning loading condition and hydrostatic information is automatically accessed by the module. This means SK requires only a few input parameters, offering unmatched ease of use.

SeaKeeping offers an excellent and economical integrated option for seakeeping and hydrodynamic analysis that is well suited to the following applications:
Seakeeping output is organized by mode (i.e. Surge, Sway, Heave, Roll, Pitch, Yaw) so it is very easy to reference specific RAOs or response results. In addition, SeaKeeping offers an optional summary table which displays the most probable extreme position, velocity, or acceleration amplitude components in the x (Surge), y (Sway), z (Heave) translational directions, and the X (Roll), Y (Pitch), Z (Yaw) angular directions for a specified confidence level. This table is an ideal "one-location" reference for design values that may be added to the end of the report.

Seakeeping reports are comprehensive, and include an initial section that summarizes input parameters, condition information, and specified critical points. A wave component summary table is also included, and if wave spectra are used, a wave spectra plot is included that shows both the continuous wave spectrum and the discrete wave samples used by SeaKeeping.

The module offers users the following features:
  1. Integration with GHS command language and run files
  2. Included graphical user interface for setting up complex analyses
  3. Use of GHS geometry files (.GF) for seakeeping analysis with little or no modification
  4. Minimal input and ease of use compared to other commercially available software
  5. Recognizes vessel loading condition as specified in GHS, no need to specify hydrostatic parameters, it is all done automatically
  6. Full support for monohull vessels
  7. 6-DOF motions including displacements, velocities, accelerations, amplitudes and phase angles
  8. Absolute and relative motions
  9. Motions computed at vessel CG and at specified critical points
  10. Response amplitude operators (RAOs) for all DOF at any point
  11. Statistical response data including response variance, RMS, average and significant response amplitudes, average periods, and extreme maxima
  12. Acceleration amplitudes may be given in Ft/Sec2, m/Sec2, or gravitational units "G's"
  13. User specified confidence limits and time intervals
  14. Optional summary table for position, velocity, or acceleration amplitudes at default or specified confidence limits at any point is an ideal "one-location" reference table for design values
  15. Robust linear, rigid-body, frequency domain, strip-theory method
  16. Boundary element method for computing 2D hydrodynamics can accomodate most ship geometry, including anti-symmetric geometric sections (i.e. non-zero heel)
  17. Advanced parameterization of hydrodynamic panel mesh
  18. Parameterized wave spectra sampling using a constant variance or frequency bandwidth method
  19. Long-crested waves at any wave heading
  20. Short-crested waves with Cosine-Squared and Cosine-Power spreading functions
  21. Regular or irregular waves
  22. Non-zero vessel speed
  23. Deck immersion or "shipping water" probabilities and frequencies computed at any point (or all critical points)
  24. Single wave or spectra wave input (via WAVE command extension)
  25. Built in wave spectra include:
  26. Five optional comma-separated output data files:
  27. Full-featured GHS report file organized by mode including:
Don't see a specific feature on the list? Contact Customer Support to inquire about current and prospective feature updates. SeaKeeping is always being updated and improved.

See the Version 16.00 Update for more information on the SEAKEEPING command.

Validation Studies:
2D Coefficients and Forces
3D Forces and Moments





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