In Assassin's Creed IV: Black Flag, Edward Kenway captains the pirate ship Jackdaw.
Edward acquires the vessel early in the story after taking the identity of the Assassin Duncan Walpole. He renames the ship Jackdaw and uses it as his base while sailing through the Caribbean during the Golden Age of Piracy.
The Jackdaw is more than transportation. Players upgrade its hull, broadside cannons, mortars, and other equipment, making naval combat and exploration major parts of the game. The ship can also be used to board enemy vessels and collect resources.
The name is sometimes confused with ships from other Assassin's Creed games. Connor's ship in Assassin's Creed III is the Aquila, while Shay Cormac commands the Morrigan in Assassin's Creed Rogue. Those vessels belong to different protagonists and campaigns.