Thanks for your answers, however I am still a bit stuck. I'll try to give a more thorough description of the problem. In the attached picture two vessels, A and B, are illustrated. The blue vectors illustrate the waves and how their angles of attack are measured. When the waves hit the vessel, there will be motions in 6 degrees of freedom; surge, sway, heave, roll, pitch and yaw.

Surge=motion along x-axis

Sway=motion along y-axis

Heave=motion along z-axis

Roll=rotation about x-axis

Pitch=rotation about y-axis

Yaw=rotation about z-axis

The data I have is called RAO (response amplitude operator) data and is equal to the amplitude of the vessel motion (in meters or radians) divided with the amplitude of the waves. As mentioned, it is between these two amplitudes the phase shift will occur. My problem is that I can't seem to figure out how the phase shifts will change for the different degrees of freedom when the data is converted from B) to A).

Any clever minds have a clue?

Dan