M_Boats: Bottom paint

My boat has ablative copper bottom paint that is over five years old, and beginning to wear off. One boatyard has suggested removing it with a pressure washer that uses very hot water rather than sanding. Does anyone have any experience with this, or comments as to whether it's a good idea or not? Any possibility of damage to the surface? Would it still have to be sanded before painting? Thanks, Rick M17 #633 Lynne L