In 1939, Walter E. Nilsson, an attorney in New York City, secured a patent for this Segway-like watercraft. The “water unicycle” provides efficient transportation for one person across the surface of a body of water. The key to its design is the weighed keel which keeps the pilot upright in the seat, pedaling the huge inflated wheel forward and backward.
Nilsson proposes using his invention to create a novel challenge in the sport of water polo, but I think that jousting would be an even better use.
Popular Mechanics favorably reviewed the design at the time of its publication in 1939, but I see no evidence that it was ever put into production. Imagine how much World War II might have been shortened had the Allied powers made prudent use of Nilsson’s genius.
-via Weird Universe