Instructions
Point your Wii remote at the pirate and shoot him with paint thinner until you have removed all of his armor.
Avoid the spin attack he performs when he has no armor. He may stagger a bit after performing this maneuver. If he does, run around to his back.
Shake the Wii remote to perform a spin attack on the pirate's back, which will damage him.
Repeat Steps 2 and 3 two more times to defeat the pirate.