GHS-SK Optional Module

The General HydroStatics SeaKeeping Module "SK" is designed to provide the GHS user with an integrated, general-purpose solution for seakeeping and hydrodynamic analyses. SeaKeeping is the result of significant in-house development work, and while it offers many features that may be found in other motions codes, it is also unique in many respects. Integration within the GHS environment also means calculations may be performed using existing geometry files, loading conditions, and run files. This translates to minimal additional user input, unmatched flexibility in its market segment, and ease of use.

SeaKeeping offers an excellent and economical solution for seakeeping and hydrodynamic analysis that is well suited to many applications. Some of the more common use-cases include:
SeaKeeping Features
The module offers users the following features: 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.

SeaKeeping Output
Seakeeping calculations create a lot of data, which is both a necessity and a curse when you are trying to review results. Seakeeping output is designed to make it as easy as possible to reference specific RAOs or response results for certain Critical Points or heading/speed combinations (a.k.a. Cases) without omitting important supporting information. SeaKeeping reports are organized according to the following structure, with options to include or omit various sections:

  2. Summary of general input parameters, including method type, geometry component, and meshing parameters.
  4. Table of user specified Critical Points, overall vessel CG, and any optional derived response points (SHW, MSI).
  5. CASE(S)
  6. Case number, case-specific wave heading and ship speed
    1. Wave Components
    2. Summary of overall wave/spectra type, wave samples, and sampling method parameters. Also includes tabulated wave period, frequency, LWL/WvLen, encounter frequency, ordinate, and amplitude for each wave component.
    3. RAOs and Phase Angles (Position, Velocity, and/or Acceleration)
    4. Tabulated RAOs and phase angles for all modes for each Critical Point. Also includes a plot for each mode, with results for all Critical Points plotted together.
    5. Response Statistics (Position, Velocity, and/or Acceleration)
    6. Tabulated response statistics for all modes for each Critical Point. Includes variance (m0, m2, m4), average periods (ZUC/Maxima), RMS, average, significant, average maxima, and optional confidence/interval extreme amplitudes.
    7. Derived Responses (Optional)
      1. Slamming
      2. Deck Submergence/Shipping Water "SHW"
      3. Motion Sickness Incidence "MSI"
    8. Case Summary Table (Optional)
    9. Table of user requested absolute response amplitudes for all modes for each Critical Point. Displays the response for the preceding case.
  8. Table of overall user requested absolute response amplitudes for all modes for each Critical Point. Displays the maximum over all cases.

To help parse especially large runs, SeaKeeping offers optional case-specific or overall summary tables which display user requested position, velocity, and/or acceleration amplitude components in the x (Surge), y (Sway), z (Heave) translational directions, and the X (Roll), Y (Pitch), Z (Yaw) angular directions. These tables are an ideal "one-location" reference point for design values or initial review, and are always located at the end of each reported case.

In addition to comprehensive reports, SeaKeeping offers six (6) optional comma-separated-variable (CSV) data files that may include any of the information found in the report in a convenient form for input into spreadsheets, third-party programs, or further post-processing by run-files.

SeaKeeping reports 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. Optional derived responses are then appended to the end of each case.

Get Access to a Trial Version
If you are interested in testing the SeaKeeping Module, contact sales to inquire about a temporary license. We will work with you to set up a trial period that meets your evaluation needs.

Validation Studies
A number of core validation studies, including coefficients, forcing, RAOs, relative motions, and accelerations, may be found here.

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