Boats (船 Fune) are vehicles used for transportation across water.
Bulma has one that is a capsule vehicle; she, Goku and Oolong boards it to go to Fire Mountain, but it breaks down and they have travel through Diablo Desert instead. Krillin is seen using one when traveling to Kame House for the first time. Shortly later, Master Roshi, Goku, Krillin, and Launch use a hoverboat to travel to Training Island.
Colonel Violet is seen driving one when looking for a Dragon Ball in a jungle. In the movie Dragon Ball: The Path to Power, General Blue's boats attack Master Roshi, Bulma, Goku, and Oolong on the beach. A boat is seen in the harbor inside the Pirate Cave, although it closely resembles a World War II-era submarine. Boats used by the Red Ribbon Army and Earth's Military are shown to be armed with various weapons such as missiles, artillery, machine guns, anti aircraft weapons, etc.
Master Shen is seen riding a big ship with all of his students to the 22nd World Martial Arts Tournament. In Dragon Ball Z, Gohan is seen surfing in the desert before constructing a raft in an attempt to escape from Piccolo. Several boats are seen in the harbor of Jaguar's island in the movie Dragon Ball Z: Bio-Broly.