page_title: Short Sunderland
section_title: Second World War
hierarchical_section_title: Short Sunderland / Operational history / Second World War
caption_attribution_description: English: U-boat Warfare 1939-1945 U-boat Losses: U 426 a Type VIIC submarine, down by the stern and sinking, after attacks by a Short Sunderland flying boat.
context_page_description: The Short S.25 Sunderland was a British flying boat patrol bomber, developed and constructed by Short Brothers for the Royal Air Force. The aircraft took its service name from the town and port of Sunderland in North East England.
  Developed in parallel with the civilian S.23 Empire flying boat, the flagship of Imperial Airways, the Sunderland was developed specifically to conform to the requirements of British Air Ministry Specification R.2/33 for a long-range patrol/reconnaissance flying boat to serve with the Royal Air Force. As designed, it served as a successor to the earlier Short Sarafand flying boat. Sharing several similarities with the S.23, it featured a more advanced aerodynamic hull and was outfitted with various offensive and defensive armaments, including machine gun turrets, bombs, aerial mines, and depth charges. The Sunderland was powered by four Bristol Pegasus XVIII radial engines and was outfitted with various detection equipment to aid combat operations, including the Leigh searchlight, the ASV Mark II and ASV Mark III radar units, and an astrodome.
  The Sunderland was one of the most powerful and widely used flying boats throughout the Second World War.
context_section_description: During the Second World War, although British anti-submarine efforts were disorganized and ineffectual at first, Sunderlands quickly proved useful in the rescue of the crews from torpedoed ships. On 21 September 1939, two Sunderlands rescued the entire 34-man crew of the torpedoed merchantman Kensington Court from the North Sea. As British anti-submarine measures improved, the Sunderland began to inflict losses as well. A Royal Australian Air Force (RAAF) Sunderland (of No. 10 Squadron) made the type's first unassisted kill of a U-boat on 17 July 1940.
  During its service, the Sunderland Mark I received various improvements. The nose turret was upgraded with a second .303 (7.7 mm) gun. New propellers together with pneumatic rubber wing de-icing boots were also fitted. Although the .303 guns lacked range and hitting power, the Sunderland had a considerable number of them and it was a well-built machine that was hard to destroy. On 3 April 1940, a Sunderland operating off Norway was attacked by six German Junkers Ju 88C fighters; during the engagement, it shot one down, damaged another enough to cause it to retreat and later perform a forced landing and drove off the rest. The Germans are reputed to have nicknamed the Sunderland the Fliegendes Stachelschwein ("Flying Porcupine") due to its defensive firepower.
  Sunderlands also proved themselves in the Mediterranean theatre. They flew many evacuation missions during the German seizure of Crete, carrying as many as 82 passengers. One flew the reconnaissance mission to observe the Italian fleet at anchor in Taranto before the famous Royal Navy Fleet Air Arm's torpedo attack on 11 November 1940.
  New weapons made the flying boats more deadly in combat. In 1939 during an accidental fratricidal attack, one 100 lb anti-submarine bomb hit the British submarine Snapper doing no more damage than breaking its light bulbs; other bombs had reportedly bounced up and hit their launch aircraft. In early 1943, these ineffective weapons were replaced by Torpex-filled depth charges that would sink to a determined depth and then explode. This eliminated the problem of bounce-back, and the shock wave propagating through the water augmented the explosive effect.
  While the bright Leigh searchlight was rarely fitted to Sunderlands, ASV Mark II radar enabled the flying boats to attack U-boats on the surface. In response, the German submarines began to carry a radar warning system known formally as "Metox", and informally as the "Cross of Biscay" due to the appearance of its receiving antenna, that was tuned to the ASV frequency and gave the submarines early warning that an aircraft was in the area. Kills fell off drastically until ASV Mark III radar was introduced in early 1943, which operated in the centimetric band and used antennas mounted in blisters under the wings outboard of the floats, instead of the cluttered stickleback aerials. Sunderland Mark IIIs fitted with ASV Mark III were called Sunderland Mark IIIAs. Centimetric radar was invisible to Metox and baffled the Germans at first. Admiral Karl Dönitz, commander of the German U-boat force, suspected that the British were being informed of submarine movements by spies. In August 1943, a captured RAF airman misled the Germans by telling them that the aircraft were homing in on the signals radiated by the Metox, and consequently U-boat commanders were instructed to turn them off.
  The Germans responded to Sunderland attacks by fitting some U-boats with one or two 37 mm and twin quad 20 mm flak guns to fire back at their attackers. While Sunderlands could suppress flak to an extent with their nose turret guns, the U-boats guns had superior range, hitting power and accuracy. Attempting to shoot down Allied aircraft did, however, prolong the U-boat's presence on the surface, which made sinking the vessel easier. Nonetheless, fitting of substantial arrays of anti-aircraft guns temporarily decreased U-boat losses while both Allied aircraft and shipping losses rose. As a countermeasure to the increased defensive armament of the U-boats, the Australi
caption: U-426, a Type VIIC submarine, down by the stern and sinking, after being attacked by a Short Sunderland flying boat.
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