Nick,
Imagine this scenario, the Helicopter in question has an underslung rotor system, is on floats and is pitching back and forth and rolling left and right. Doesn't an underslung system allow the fuselage to behave like a pendulum?, which means Lu's statement "This constant fuselage displacement will cause the rotor system to constantly change in relation to the fuselage." is correct. Although the rotor system is moving in relation to the fuselage the rotor system is effectively not moving but maintaining its position in space and the fuselage is the item that is moving.
Now what about a helicopter with a rigid head?, Lynx for example (no I haven't seen one on floats either), I think because of the rigidity between the rotor system and the fuselage if a wave tried to roll the helicopter then we would see an excellent demonstration of precession i.e. it would either pitch forward or backwards respectively.
And while were at it can we stop the personal attacks / insults?
Jiff