began catamaran production at their boat factory in Canvey Island, Essex, England in 1954 The Prout Brothers, Roland and Francis owned their boat factory since 1935, and they began experimenting with catamarans as early as 1949. Their Shearwater catamarans won races easily against the monohulls. Yellow Bird, a 1953-built Shearwater, raced successfully by Francis Prout in the 1960s, is in the collection of the National Maritime Museum Cornwall. Catamarans, informally called “cats” are multi-hulled watercraft featuring two parallel hulls of equal size. It is a geometry-stabilized craft, deriving its stability from its wide beam, rather than from a ballasted keel as with a monohull sailboat. The catamaran's wider stance on the water can reduce both heeling and wave-induced motion, as compared with a monohull. Catamarans range in size from small (sailing or rowing vessels) to large (naval ships and car ferries).