Von Brunel's Magnificent Sub-Hydro Velocipator of Proven Durability

After floating adrift of several days in a barrel after an unfortunate incident involving a mistimed pigeon bomb fuse an an angry ship's captain, Engineer von Brunel wondered if there might not be some mileage in developing such a humble conveyance into something more ingenious. After much persistence, Brunel was able to convince the Prince of Altdorf that he could develop a system whereby a man could travel beneath the waves in such a device and, if equipped with a drill, punch holes in the hulls of enemy ships. Working in conjunction with the city's finest coopers, Brunel fashioned an undersea Velocipator that could travel for nearly a hundred yards before the breathless pilot was forced to surface. A system of pipes and tubes was introduced to allow the pilot to breathe, but further attempts to perfect the device were abandoned after Brunel himself piloted the Velocipator and it flooded, the wood having warped after such continued immersion and sent him to the bottom of the Reik.

Source
pg. 52
 * White Dwarf #296