You need to check the title laws in your state but it is possible to get a new title usually.
First I would start with the Mfgr and see if they will issue you a new one. If not then try at the local court house and see what they say regarding a new title. Your state probably doesn't title boats that are that small anyway, I think I would just ask how you register the boat with a bill of sale, if it isn't a title state you may not have a problem.
My concern would be, does his bank have the MSO and did he pay it off or keep the $$ and now the bank is going to come looking? You should be able to do a UCC filing search, most states have this online and see if there is a bank that had a filing for inventory, which this would be. They would likely have the MSO.