Polar Tang

The Polar Tang is a submarine serving as the ship of the Heart Pirates. Its name was revealed in Volume 82's SBS.

Ship Design and Appearance
The Polar Tang is a submarine that is green in the front and yellow in the back. Unlike most pirate ships, it is mostly made out of metal and runs on engines instead of sails. The upper decks are made of wood, though, and there are two tall masts on both the front and back levels. Circular windows line the craft, and the Heart Pirates' Jolly Roger and Law's "DEATH" tattoo are plastered on the exterior. There are also lights resembling streetlamps on the outside in order to allow sight underwater.

Inside the ship is an advanced medical room, where Law can perform operations on patients.

Marineford Arc
The Heart Pirates came to Marineford on the Polar Tang in order to save Monkey D. Luffy. They fled Marineford with Luffy and Jinbe, managing to evade Aokiji's Ice Age and Kizaru's Yasakani no Magatama attacks. Later, Law turned the recovering Luffy and Jinbe over to Boa Hancock on a stolen Marine ship.

Post-War Arc
Unlike the other Supernovas, Law decided not to take the Polar Tang and his crew to the New World just yet, and to stay in Paradise slightly longer.

Zou Arc
After the Ninja-Pirate-Mink-Samurai Alliance was formed, the Heart Pirates set sail for Wano Country in the Polar Tang along with some of the Straw Hat Pirates and the Kozuki Family retainers.