From the Super Mario Wiki
Retrieved from "https://www.mariowiki.com/index.php?title=Boat_Mario&oldid=2394264"
Boat Mario is an origami-like transformation in Paper Mario: The Thousand-Year Door. It allows Mario and his partners to traverse across water unscathed; waves will push the boat back, however. Like his other origami-themed forms, the boat form is granted to him in the form of a "curse" from one of the Black Chest Demons in Pirate's Grotto, where it is primarily used; also like the other forms, it is used in a minigame in the Pianta Parlor.
It is similar to Mario's plane form in that it can only be activated when Mario is on the form's corresponding panel, though it requires Mario to touch another panel in order to return to normal.