My boat is a 26s so, I can't be of much practical help. Here are some ideas, use each at your own risk.
1. Boat on trailer: go buy a length of thin aircraft cable from your local hardware (e.g. 1/8"), that largest that will slide down the side of your cb trunk. Drop one end down the forward outboard side, the other down the aft outboard side. Now you should have two ends hanging out the bottom of the slot on the bottom of the boat. Now drop down the center of the cable and you should have the offending bolt captured. Pull like heck to unlodge. Note: If you believe the offending bolt to be at the top figure out how to reverse the process and feed the cable up rather than down.
2. If the boat is still in the water ---??
Lots of luck.