The Shark Submerge III is a deep-sea exploring submarine shaped as a shark that can carry three people. It is a part of the Thousand Sunny's Soldier Dock System and can be deployed by the number 3 channel.
Ship Design and Appearance
The Shark Submerge III is a small three-man submarine shaped like a shark. It was built by Franky in order to aid the Straw Hats should they ever come across a situation that requires going underwater. It has a Den Den Mushi so that the members of the Straw Hat crew that are using it can keep in touch with the rest aboard the Thousand Sunny. The Shark Sumberge III has a diving limit of 5,000 meters. Going below any further than that would cause the sub to crack due to the surrounding water pressure.
Anime and Manga Differences
Originally in the manga, the Shark Submerge was first shown when the Straw Hats when Franky explained about the Soldier Dock System in Thriller Bark. While shown, however, it wasn't until the crew reached the second half of the Red Line that the submarine was seen being used to look for Fishman Island. In the anime, the Shark Submerge was first shown and used during the Ice Hunter Arc.