PT Boats are patrol torpedo boats. Very fast and very light wooden boats armed to the teeth with deck guns, torpedoes, depth charges, machine guns, smoke generators, rockets, and (believe it or not) more.
PT boats to other ships are basically what fighter planes are to bombers.
My grandafther commanded a PT boat in WWII and he says a formation of PT boats with competent crews was an almost unbeatable weapon. They would come in at an extremely high speed, maneuvring wildly and easily avoiding defensive fire from higher caliber weapons. They'd hurl torpedoes at the enemy from out of effective small arms range and retreat. He says late in the war they'd see people jumping overboard and lowering life boats as soon as his PT boats were in sight.
This should definitely be more fun that commanding a destroyer or a submarine.