Fighter catapult ships also known as Catapult Armed Ships were an attempt by the Royal Navy to provide air cover at sea. Five ships were acquired and commissioned as Naval vessels early in the Second World War and these were used to accompany convoys. The concept was extended to merchant ships which were also equipped with rocket assisted launch systems and known as Catapult Aircraft Merchantmen (CAM ships).
The ships 
There were five fighter catapult ships, collectively known as the Pegasus class. Two, Patia and Springbank were lost during the war. They were each equipped with a single Fairey Fulmar or "Hurricat" (an adapted Hawker Hurricane Mk.1A).
||Former Ocean Boarding Vessel, converted to a catapult ship in 1940, war service in the Atlantic after being damaged repaired in 1943 and returned to merchant use.
||Former Ocean Boarding Vessel. Maplin saw war service in the Atlantic in 1940. She was a training ship from 1941 to 1944, in reserve from September 1944 and subsequently an accommodation ship. Maplin's war service was focused on Atlantic convoys and her "Hurricat" was the first to destroy an enemy aircraft, a Focke-Wulf Fw 200 "Condor" in August 1941. The pilot was Robert W H Everett of 804 Naval Air Squadron.
||Former Ocean Boarding Vessel. Lost 1941 Foundered after bombing attack
||Commissioned as seaplane carrier HMS Ark Royal in 1914, renamed Pegasus in 1934.
||Former auxiliary anti-aircraft cruiser. Torpedoed and sunk 27 September 1941.