RedactedNarrative: V1 WAS TRAVELING SOUTHBOUND IN THE ICW CHANNEL OF MADEIRA BEACH, SOUTH OF THE TOM STUART CAUSEWAY. V1 WAS PASSING THE RESUME NORMAL SAFE OPERATION SIGN LOCATED JUST NORTH OF MARKER 8 AND MARKER 9 OF THE ICW. OP OF V1 ADVISED THAT HE BEGAN TO ACCELERATE TOA FULL PLANE WHEN THE MOTOR BEGAN TO BOG DOWN. oP ADVISED THE TRANSOM OF THE VESSEL BEGAN TO SINK AND WATER STARTED POURING OVER THE TRANSOM INTO THE BOAT. HE AND OCCUPANT JUMPED INTO THE WATER AS THE VESSEL WAS SINKING AT A HIGH RATE. OP STATED THE VESSEL WAS UNDER IN LESS THAN 10 SECONDS. NO INJURIES WERE REPORTED.  A GOOD SAM. ASSISTEB THEM OUT OF THE WATER.  THE VESSEL WAS RECOVERED BY COMMERCIAL SALVAGE. NO BILGE PLUG INSTALLED