A specialised type of vessel, built around an inboard engine (of either internal combustion or gas turbine type) optimised specifically for performance, often within defined specifications or formulae. Such craft may be used for competition (in racing or by record-breaking) or experimental purposes, and are commonly kept ashore, being used only in sheltered waters under favourable conditions. The hulls may be of displacement, planing or hydrofoil form, the second being the most common.
