Battle Ensign of U-570

Displayed in the anti-submarine warfare section of the Second World War gallery at the Royal Air Force Museum Hendon's location outside London is the battle ensign of U-570, a Type VIIC German U-boat.  The U-570 surrendered to an Iceland-based Lockheed Hudson aircraft of No. 269 Squadron RAF on 27 August 1941.  Attacked by two Hudsons while surfaced, U-570 crash-dived but was forced back to the surface after being depth charged and strafed by machine gun fire.  Repeatedly attacked, the U-boat's crew eventually displayed a white flag of surrender.  The RAF maintained a constant presence over U-570 through relays of aircraft circling overhead until a Royal Navy destroyer arrived over ten hours later to capture the U-boat and take its crew prisoner.

Towed to Iceland and beached, U-570 was eventually salvaged, sailed to the UK, and renamed HM Submarine Graph.  Having been captured intact, U-570/Graph was subjected to a detailed inspection and analysis, allowing British authorities to learn about its operating capabilities.  Of particular note, it was discovered that the Germans had produced the strongest hull known in maritime architecture, capable o withstanding 14 tonnes of pressure per square foot of water pressure at 500 feet (152 metres).  This revelation led to the immediate modification of detonators on ship-launched depth charges to permit them to be triggered at 600 feet (183 metres), thereby ensuring higher probability kills in the future. 

HM Submarine Graph went on to make three combat patrols with a Royal Navy crew, thereby becoming the only U-boat to serve both the Axis and the Allied cause in the Second World War.  Withdrawn from service on 21 June 1943 due to mechanical defects and challenges in maintaining the German-designed submarine, Graph survived depth charge testing and was en route to be scrapped in Scotland when, on 20 March 1944, the tow line broke and the submarine was driven ashore on the Isle of Islay and abandoned.            

Photo taken 4 May 2022

The battle ensign from German U-boat U-570, on display at the Royal Air Force Museum, Hendon, North London, UK.  This ensign was given to Squadron Leader James Thompson, the pilot of one of the RAF Hudson bombers that forced U-570's surrender.

A Lockheed Hudson light bomber and coastal reconnaissance aircraft like the one that that forced the surrender of U-570 on 27 August 1941. (Photo courtesy of https://www.lockheedmartin.com/en-us/news/features/history/hudson.html)