I'm not an attorney in California, but you don't want to do anything fraudulent like buying the boat for an unrealistic amount. That would definitely trigger more scrutiny from a bankruptcy trustee. If he hasn't filed, I'd try to reason with the bank, if you can find intelligent life. If not, I'd try to reason with the bankruptcy trustee, if it gets that far.
As Dave Ramsey says, the only ship that won't sail is a partnership.