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Positioning Application: What is the ship sea state model based on and how were the default values chosen?

Environment/Versions
  • PosApp (SimGEN / SimREPLAYplus / SimREPLAY)
Answer
  • The sea state model categories are based on the "Beaufort Scale". The following link is one suitable reference

    https://www.metoffice.gov.uk/weather/marine/guide/beaufortscale.html
     
  • The choice of default sea state values are an arbitrary set, determined when the ship vehicle was originally implemented in the Spirent 'SimGEN' software approximately 20 years ago!
  • They are intended to provide a suitable demonstration of the relative differences that could be expected between the different sea state categories
  • Spirent does not periodically update them to match any current maritime data for such sea states
     
  • The three sea state effects - Roll, Pitch & Heave, are simulated using simple sinusoidal equations, where
        - A = amplitude (entered via the GUI)
        - w = rate (entered via the GUI)
        - p = phase (entered via the GUI)
        - t = time into run
    • For Roll & Pitch (degrees) = A*sin[(wt*360) + p]
    • For Heave (metres) = -A*sin[(wt*360) + p]

 

NOTE: SimREPLAYplus & SimREPLAY users cannot create ship scenarios. They may only review the conditions pre-defined in those ship scenarios that they may have.

Product : SimREPLAYplus,SimREPLAY,SimGEN,PosApp,Ship