The Surface Fleet is the name given to the collection of surface vessels (as opposed to submarines or aircraft) of the Royal Navy. At present it consists of two flotillas based at Portsmouth and Devonport, both on the south coast of England, and a flotilla based at the Clyde Naval Base at Faslane in Scotland. The Surface Fleet consists of a wide variety of vessels, ranging from aircraft carriers to mine countermeasures vessels to offshore patrol vessels, but the backbone of the fleet consists of destroyers (type 45) and frigates (type 23).