No Gonzo, that's not so, it seems that you have no clear idea of the phenomenon we are dealing with. When a boat rotates a certain angle to, say, the X axis, the effects are totally different depending on the origin of coordinates is considered. Therefore, even talking about angles, knowing where the axis of rotation is very important.
For angles, as for distances, nothing is relative, everything must be measured from the proper source, in absolute coordinates, not related. As you well know, because, as you say, you're a designer, the boat shafts that the designer takes to calculate the hydrostatic properties are different from those used to determine the heeling or trim for a load condition.
For angles, as for distances, nothing is relative, everything must be measured from the proper source, in absolute coordinates, not related. As you well know, because, as you say, you're a designer, the boat shafts that the designer takes to calculate the hydrostatic properties are different from those used to determine the heeling or trim for a load condition.