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.
Rear-view of the Polar Tang.
Luffy hooked up to one of the life-support systems.