For a more definitive answer, consult with a bankruptcy attorney to strategize the best way to protect your assets and income--given how much money is at stake, it would be well worth the cost of doing so.That said, as a general matter, voluntarily surrending a vehicle which secures a loan does not itself prevent the lender from then suing you for the balance--in your example, if you owe $100k and the boat would bring $50k when sold at auction, the lender could conceivably pursue you for the other $50k. (Obviously, if the lender agreed to accept the boat in full satisfaction, that would be different, but such agreement is voluntary on the part of the lender.)However, if you file bankruptcy, that should discharge a debt like the one you describe. The bank will get its appropriate share, as one of your creditors, from the bankruptcy, but that should be it.