in early World War II the British used obsolete land versions of the Hurricane I, launched from merchant ships by catapult, to deal with mid-ocean convoy harrassment by the long range FW200's, which would fly from Bordeaux to Stavanger or back. The g-forces upon launch would cause temporary pilot blackout, and the pilot would have to ditch beside a ship upon downing or chasing away the FW.
http://www.fleetairarmarchive.net/Aircraft/seahurricane.htmWhen it became clear that the Hurricane was becoming outclassed as a pure fighter, other duties were assigned to it, including as the Sea Hurricane. The Royal Navy was keen to acquire the Hurricane to help in the Battle of the Atlantic which, in early 1940, had a steep rise in shipping losses far from shore, in areas where land- based aircraft could not provide air cover for Allied convoys. This gave rise to the 'Hurricat', a converted Hurricane carried by CAM-ships. Hurricanes converted for such a role needed only the addition of catapult spools, and 50 Hurricane Mk I land-planes so modified and designated Sea Hurricane Mk IA.
