If the boat is a whale watching boat it is probably a commercial
boat. This means that it must be documented which means registered with the federal government
and more specifically the USCG. The owner of a documented vessels is public information. So it should be no problem finding out who the owner is by contacting the Coast Guard. After you obtain the name of the individual or the corporation that owns the vessel, you will need to hire the services of a process server to serve the documents. They know how to find people, hiding or not.
A title transfer of a documented vessel is done through the Coast Guard, therefore they will know who is the current
owner and who was the owner at the time of the incident.