RedactedNarrative: O1 V1 FINISHED PULLING HIS KIDS ON A TUBE WHEN HE WENT TO RETURN TO SHORE HE INCREASED POWER CAUSING HIS TRANSOM TO DROP.  WHEN THE TRANSOM OF V1 SANK INTO THE WATER AND HIT A ROCK.  THE SKAG BROKE, BROKE ONE BLADE OFF, BROKE ONE OTHER ONE AND BENT THE THIRD OFF THE ALUMINUM PROPELLER AND BENDING THE PROPELLER SHAFT.  O1'S INEXPERIENCE AND LACK OF KNOWLEDGE OF THE LAKE CONTRIBUTED TO THE ACCIDENT.