Back them up!: The capture of the German submarine U570 by a Lockheed "Hudson" of the British Coastal Command

U-570 (later HMS Graph) held the curious title of the only German U-boat captured by an Allied aircraft, and was the only U-boat to serve for both the Allied and Axis powers during the Second World War. This poster depicts the moment when the either the Lockheed Hudson flown by Flight Sergeant Leslie Mitchell of 269 Squadron (British Coastal Command) initially spotted the U-570 (but could not attack as its depth charges were jammed), or the Hudson flown by Squadron Leader James Thompson, which was able to cripple the vessel, circling it until Allied ships were able to take it prisoner.

The capture of U-570 was part of an Allied plan to issue fake wireless reports of a merchant shipping convoy off the coast of Iceland on 23 August 1941, with the intention of capturing a U-boat or similar (with the likely target an Enigma Machine). U-570 was the first to respond to this as part of its first mission following its launch on 15 April 1941. Based in Norway, it was commanded by Captain-Lieutenant Hans-Jaochim Rahmlow as his first U-boat command. Owing to an inexperienced crew and rough sees, seasickness was rampant on its voyage to the perceived Allied position, such that on 27 August Rahmlow broke with protocol and surfaced the vessel. This was the point where it was spotted by 269 Squadron and subsequently captured. With depth charges damaging the vessel, causing batteries to leak and the ship taking on water, it was rapidly towed to Iceland, patched up, then sent to Britain for study.

Following the in-depth study of the vessel, U-570 was commissioned into the Royal Navy, on 19 September 1941, as HMS Graph with the pennant number P715. In the Royal Navy HMS Graph would only undertake 3 missions, when a shortage of spares, as well as general defects led to its decommission from active service, where it was transferred to training duties.

This poster was one of a series in the same format that depicted different achievements, notable events, or activities of interest by the different branches of the armed forces. These posters aimed to increase home front support for the war and to boost morale.

At the bottom of the poster, beneath the image, is the title 'BACK THEM UP!' This series was also published under the alternate title "INTO ACTION".