The first thing I'd check would to make sure that every thing is OK with the engine's raw water cooling system. I forget his name, but I used to converse with a guy that once had to have the Coast Guard drop him a pump. When he got the boat dewatered, he was able to discover that the cooling water wasn't being expelled with the exhaust. I don't remember the reason, but it was probably a broken hose or some such.

He said the accuracy of the drop was amazing. The pump landed on one side of the boat and the parachute on the other with the lines strung across the boat.