The Sea Shepherd's Steve Irwin is officially a yacht. (I learned this from Hawspiper) - That makes Paul Watson a yachtsman.
Yachtsman - the first thing that popped into my head is Sir Francis Chichester. He was justifiably considered to be an expert seaman. On the other end of the scale is Al Czervik, the fictional character played by Rodney Dangerfield in the movie Caddyshack.
Paul Watson falls somewhere on the scale between Dangerfield's Al Czervik and Sir Francis Chichester. Rodney Dangerfield's character at least hired a professional captain, Paul Watson should do the same.
UPDATE: Fred Fry informs that the Steve Irwin is a fishery support Vessel - the movie clip of Dangerfield is still funny though - and Watson is still no seaman.