Boatswain (The Curse of the Black Spot)
A boatswain was a pirate on board the Fancy in the 17th century.
He disagreed with Captain Avery's decision on how to protect themselves from the Siren. Mulligan and he decided to leave the ship until Toby cut his hand, giving him the black spot. He was imprisoned in the armoury by his captain and then taken by the Siren to her ship. He joined the rest of the crew when they took the ship for themselves. (TV: The Curse of the Black Spot)
Some time later, the Eleventh Doctor recruited Avery to help him with an attack on the asteroid of Demons Run to rescue Amy Pond. The boatswain and the crew boarded Madame Kovarian's ship during the attack and subdued its crew, preventing her escape. (TV: A Good Man Goes to War)