What underwater equipment did Leonardo da Vinci sketch for a diver?

Leonardo da Vinci sketched a diving suit for a person working underwater.

The design is associated with a sealed suit, a breathing arrangement, and tubes extending toward the surface. Leonardo proposed it during his investigations of military and engineering problems, including the possibility of underwater activity near enemy vessels.

The concept belongs to the history of diving equipment, but it was not a modern scuba suit. It lacked the compact, pressurized air cylinder and regulator used by contemporary recreational divers. Leonardo’s proposal depended on air being supplied through tubes, creating practical problems involving breathing resistance, water pressure, and tube damage.

The idea is often linked to sabotage missions, but the surviving evidence does not show that Leonardo’s suit was successfully built or used. A diving bell is a different device: it encloses an air space rather than fitting as a complete suit around the diver.