Is it correct that spherical buoy doesn't rotate?(Buoyancy)

[kevin_tee]

Does spherical buoy doesn't rotate when subject to wave compare to rectangular buoy? If only buoyancy is taken into account only. Here is the picture I draw trying to explain.

My reason is that the water that is touching the spherical buoy experience the same geometry on any surface of the sphere.

 

[A.T.]

If only buoyancy is taken into account only.

Buoyancy is due to pressure forces which act perpendicular to the sphere's surface, and thus don't create any torque around it's center of mass.