Pirate Ship

Tetra's Ship is a large, one-masted vessel with a single square sail. It plays a significant role in Link's adventures in The Wind Waker and Phantom Hourglass. Throughout the game, it is used as transportation across the Great Sea as well as a challenge to acquire new items.

The Wind Waker
In The Wind Waker, Tetra's ship makes an appearance very early in the game. It is seen pursuing the Helmaroc King, with Tetra gripped in its talons. The pirates use a large boulder fired from a catapult to attack the bird, causing it to drop Tetra on the summit of Outset Island's mountain. After being rescued by Link, Tetra returns to her ship, now docked at Outset. After some convincing from Quill the postman, she agrees to take Link to the Forsaken Fortress on board her ship.

During the long voyage, Link is sent below-decks to see Niko, the lowest-ranking member of the crew. After a rope-swinging obstacle course, Niko gives Link the Spoils Bag. Upon their arrival at the fortress, Link is catapulted inside in a barrel. Tetra's ship remains hidden behind a large rock while they wait for Link. When they see Link being tossed into the sea by the Helmaroc King, it is assumed that the pirates fled.

Later in the adventure, Link arrives at Greatfish Isle, now cursed. Quill arrives to tell Link that Tetra's crew is seeking Nayru's Pearl, and the pirate ship is docked at Windfall Island. Link sails to Windfall, where the pirates are in the process of robbing the bomb shop. Link sneaks aboard their ship and steals a bomb bag to use at Outset Island.

After the final battle with Ganon, Hyrule Castle floods, sending Link and Tetra back to the surface, where they are rescued by Tetra's loyal crew. They are pulled out of the water onto the deck of Tetra's ship.

Phantom Hourglass
In Phantom Hourglass, Tetra's ship is only seen in the opening and closing cutscenes. It is explained that Link joined the pirate crew after the events of The Wind Waker, and set sail with Tetra in search of "new lands." At the end of the game, Link and Tetra get back on board the pirate ship, and it is assumed that they set sail for more adventure.

Trivia

 * Historically, with it's single square-rigged mast and wooden construction Tetra's ship could be labeled a Cog: a historical ship from the 10th-12th century. This sort of construction would prevent it from sailing into the wind, but in either game it's not mentioned, or is not a factor.