The boat owner gave it to his son, who ended up getting insurance for the boat. The title for the boat was never changed.
more info needed.
insurance usually follows the vehicle but you should meet with a civil litigator who can review the policy.
Who was driving the boat at the time of the occurrence? Typically insurance follows the vehicle. That means even if someone else was driving the boat at the time of the occurrence the driver should be covered.
Potentially, since the title never changed. An attorney will need to review the policy and do a coverage analysis.