Reply To: Heave get negative

[Shuangxing Du]

Getting the heave negative may not be a problem. It just indicates that the COG z-position is below water surface in the time domain analysis.

Please check the followings:

(1) the global coordinate system's origin is defined at the mean water level and z-axis points upwards.

(2) from Hydrodynamic Diffraction -> Solution -> Hydrostatic, check if Ceter of Gravity Position is what you expect.

(3) from Hydrodynamic Diffraction -> Solution -> Hydrostatic, check if Actual Volumetric Displacement is nearly the same as Equivalent Volumetric Displacement.

(4) from Hydrodynamic Diffraction -> Solution -> Hydrostatic, check if horizontal position (x,y) of Center of Buoyancy to be nearly the same as that of Center of Gravity position.