Hydrocycle
Image:Man operating water tricycle, ca. 1900.jpg
A hydrocycle is a bicycle-like watercraft. The concept was known in the 1870s as a water velocipedeEdward H. Knight, Knight's American mechanical dictionary ... (New York : Hurd and Houghton, 1877), vol. 3, p. 2698 and the name was in use by the late 1890s.{{cite book
| title = Oxford English Dictionary
| quote = hydrocycle n. [cycle n. 11] a velocipede adapted for propulsion on the surface of water. 1898 River & Coast 9 July 13/1 One of the most interesting items was the Hydrocycle versus Skiff Race.}}
Power is collected from the rider via a crank with pedals, as on a bicycle, and delivered to the water or the air via a propeller.{{cite web
| url = http://lancet.mit.edu/decavitator/
| title = Decavitator Human-Powered Hydrofoil
| publisher = Massachusetts Institute of Technology
| access-date = 2011-07-22}} Seating may be upright or recumbent, and multiple riders may be accommodated in tandem or side-by-side.{{cite news
| title = Upon the seat of a water-bicycle built for two
| url = http://www.stuff.co.nz/southland-times/news/5222801/Upon-the-seat-of-a-water-bicycle-built-for-two/
| publisher = Fairfax New Zealand Limited
| author = Alana Dixon
| date = 2011-07-02
| access-date = 2011-07-22}}
Buoyancy is provided by two or more pontoons or a single surfboard,{{Citation needed|date=October 2015}} and some have hydrofoils that can lift the flotation devices out of the water.{{cite web
| url = http://www.human-powered-hydrofoils.com/hydrofoils/wetwing/
| title = Wetwing
| publisher = Human Powered Hydrofoils
| access-date = 2011-07-24}}{{cite web
|url=http://www.freaksport.com/de/sports/hph.html
|title=Muskelbetriebene Tragflächenboote
|publisher=FreakSport
|access-date=2011-07-24
|url-status=dead
|archive-url=https://web.archive.org/web/20111117102012/http://www.freaksport.com/de/sports/hph.html
|archive-date=2011-11-17
|url=http://www.waterbike.eu/Articles/WKEutin2001/WKEutin2001.html
|title=Human Powered Boats World Championship in Eutin
|date=21–22 July 2001
|author=Leo de Vries
|publisher=World of Waterbiking
|access-date=2011-07-24
|url-status=dead
|archive-url=https://web.archive.org/web/20120328033649/http://www.waterbike.eu/Articles/WKEutin2001/WKEutin2001.html
|archive-date=28 March 2012
}}
Brands include Seacycle, Hydrobike, Water Bike, Seahorse (Cross Trek){{cite web|url=http://www.seahorsefun.com/
|title= Seahorse Bike Powered Airboat}} and itBike. Kits exist to temporarily convert an existing bicycle into a hydrocycle.{{cite web
| url = http://newatlas.com/go/2505/
| title = Shuttle-Bike - convert a bike to a pedal-power boat
| author = Mike Hanlon
| date = June 4, 2004
| publisher = GizMag
| access-date = 2011-06-24}}