The term skiff is used, and has been used, to refer to many various types of small boat. The word is related to ship and has a complicated etymology: "skiff" comes from the Middle English skif, which derives from the Old French esquif, which in turn derives from the Old Italian schifo, which is itself of Germanic origin (German Schiff). "Ship" comes from the Old English "scip", which has the same Germanic predecessor. In American usage, the term is used to apply to small sea-going fishing boats. It is referred to historically in literature in Moby-Dick by Herman Melville and The Old Man and the Sea by Ernest Hemingway. The skiff could be powered by sails as well as oars. One current usage of skiff is to refer to a typically small flat-bottomed open boat with a pointed bow and a flat stern originally developed as an inexpensive and easy to build boat for use by inshore fishermen. Originally designed to be powered by rowing, their form has evolved so that they are efficiently powered by outboard motors. The design is still in common use today for both work and pleasure craft. They can be made of wood or other materials. The Thames skiff is a round-bottom clinker-built rowing boat that is still very common on the River Thames and other rivers in England. It features in Three Men in a Boat by Jerome K. Jerome, the book about a journey up the Thames. During the year, skiffing regattas are held in various river-side towns in England—the major event being the Skiff Championships Regatta at Henley. The term skiff is also used to refer to a type of high performance sailing dinghy, one that usually features an asymmetrical spinnaker and requires that the crew use a trapeze to help balance the boat. Examples include: Cherub Skiff, 12ft Skiff, International 14 (14 ft skiff), 16ft Skiff, 18ft Skiff, 29er, 29erXX, 49er and Musto Performance Skiff. The SKUD 18 was a 2-person keelboat based on the skiff universal design, which made its debut in the 2008 Paralympic Games. The SKUD's 2008 class rules required disabled sailors to be secured to their centerline seats, the boat balanced by its lead-assisted keel. Julian Bethwaite, who also designed the Olympic-class 49er skiff as well as the 29er and 29erXX, shares credit with Access Dinghy designer Chris Mitchell for design of the Paralympic-class SKUD 18. There is a Central American/Mexican version of a skiff, generally called a panga.