Are you sure the title ever was branded? and if so... Why, was it an a "total" accident for sure? or just a insurance claim. NOT all claims brand the title.
Reason I ask is in the repo world, many lenders have policies that help cover any loss if the boat is repo'd. Depending on how the boat looked or the amount of money owed, and the relationship between the bank and ins rep... It may have been salvaged to pay off the note?
Kind of long winded and alot of variables, but you get the picture...
You also need to take into consideration what you paid for the boat now? If it was a smokin deal, regardless of the history, it is going to be hard to justify any loss, and trust me when I tell you... Attorneys make the most in any law suit... Just becarefull you are persuing something that makes sence financially not just emotionally. Good luck.