Umibozu

The Umibozu is a submarine belonging to the Laotour Bandits.

Ship Design and Appearance
The Umibozu is a relatively small submarine with a white and orange frame. It has several circular windows and three barrels on each on side of it. There is a periscope at the top of it and a propeller at the back. The bow has a large spiked decoration.

The submarine is propelled by pedaling.

Great Hidden Treasure of the Nanatsu Islands
The Umibozu was first introduced to the Straw Hat Pirates by Otsu for their mission to invade the Fortress of Zilpah on Hi Island. Later, the Straw Hats use the Umibozu to dive through an underwater cavern connecting the sea to Muika Lake on Mu Island.

Trivia

 * Umibōzu ("sea priest") is a yōkai from Japanese folklore.