On 09/06/2012 OPERATOR TOOK SEVERAL FRIENDS OFFSHORE IN THE GULF OF MEXICO FOR A DAY OF SCUBA DIVING. THEY PROCEEDED TO THE TREASURE ISLAND REEF LOCATED APPROXIMATELY 6 MILES WEST OF JOHNS PASS. UPON ANCHORING THE VESSEL IN 3 TO 4 FOOT SEAS, VESSEL TOOK A WAVE OVER THE STERN AND BEGAN FILING WITH WATER. THE BILGE PUMP WAS UNABLE TO KEEP UP WITH THE AMOUNT OF WATER THAT WAS ENTERING THE VESSEL WHICH CAUSED TO BECOME SWAMPED. THE VESSEL BECAME SUBMERGED UP TO THE GUNNELS BUT DID NOT COMPLETELY SINK. THE VESSEL WAS TOWED IN BY TOW BOAT US AND TURNED OVER.