HMS Dasher (D37) was a British Royal Navy aircraft carrier, of the , converted merchant vessels, and one of the shortest-lived escort carriers. She served in the Second World War and sank on 27 March 1943. Design and description The Avenger-class escort carriers were converted U.S. Maritime Commission (USMC) type C3 American merchant ships. Their design was based on the United States Navys (AVG1). To differentiate between the two classes, the Royal Navy ships were prefixed with a 'B' (BAVG). HMS Dasher (BAVG4) was built by the Sun Shipbuilding and Drydock Company, Chester, Pennsylvania. The ship was originally named Rio de Janeiro, intended for passenger/cargo service with Moore-McCormack Lines, laid down as yard hull 189, USMC hull 62 on 14 March 1940, launched on 11 April 1941. She was converted to an escort aircraft carrier in the Tietjen & Lang shipyards New Jersey and commissioned into the Royal Navy on 2 July 1942. Dasher had a complement of 555 men and an overall length of , a beam of and a draught of . She displaced at normal load and at deep load. Propulsion was provided by four diesel engines connected to one shaft giving , which could propel the ship at . Aircraft facilities were a small combined bridge–flight control on the starboard side and above the long wooden flight deck, one aircraft lift , one aircraft catapult and nine arrestor wires. Aircraft could be housed in the half hangar below the flight deck. Armament comprised three single-mounted 4-inch dual-purpose guns, two forward and one aft, and fifteen 20 mm cannon on single or twin mounts. She had the capacity for 15 aircraft which could be a mixture of Grumman Martlet or Hawker Sea Hurricane fighters and Fairey Swordfish torpedo bombers. Service history The ship was transferred to the Royal Navy and commissioned into RN service as HMS Dasher (D37) on 2 July 1942. She participated in Operation Torch, with her sister ship , carrying Sea Hurricanes of 804 Naval Air Squadron. After aircraft ferry duties in the Mediterranean, Dasher sailed to the Clyde in March 1943 and, having had her flight-deck lengthened by , she embarked Fairey Swordfish aircraft. She escorted one convoy successfully, but shortly after leaving with the second, Dasher suffered engine trouble and turned back. Shortly after getting to the Firth of Clyde on 27 March 1943, she suffered a major internal explosion and sank.