#1. Get the boat professionally surveyed in detail.
#2. Most lawyers can handle this case, but having a survey in hand will get you an opinon quicker and plan a course of action easier. There are attorneys that specialize in manufacturing defects.
#3. I usually do not recommend lawyers but I do know of a firm in Detroit called Charfoos and Christensen PC. They handled and won the Korean Airliner case against the Russians some time back. They handle product defects and liability. They are always open to reviewing a case and they are the best folks I know of for your situation. An opinion is as easy as a fax and phone call away. Ask for Larry Charfoos.