RedactedNarrative: Operator/owner and passengers set up in the morning to fish at Stellwagen Bank. Before he left he checked the engine room and there were no issues and the bilge was clean. On the ride back they were going about 14-15 mph and he noticed the starboard engine had a little black smoke. He throttled back at that time to about 11-12 mph. Just before the Hull Gut the starboard engine died. He tried to restart it and heard an alarm go off but could not be sure where it was coming from. He put the port engine in neutral and shut off the starboard and went down from the bridge and could see smoke along the stern and flames coming out from behind the couch on the starboard side of the cabin. He attempted to extinguish the flames but couldn't and all parties abandoned ship. They did not have time to put on life jackets but being a lot of boat traffic in area they were not too concerned. They were recovered from the water. Fire boats arrived and put out fire and it sunk. It was determined the starboard engine exhaust manifold had a hole in it and hot exhaust gasses emitted onto wood interior structure causing fire and a total loss.