Vessel 1 was on the beach, vessel 2, a houseboat, attempted to beach near vessel 1.  Vessel 2 was unable to maneuver onto the beach.  After unsuccessfully beaching the vessel backed up a short distance and attempted to make a left hand turn.  While attempting the left hand turn, the stern of vessel 2 struck vessel 1's swim platform and forced vessel 1 further up onto the beach than were it had been prior to the crash.
Stoddard