page_title: Valentin submarine pens
section_title: Bombing
hierarchical_section_title: Valentin submarine pens / Bombing
caption_attribution_description: English: Royal Air Force Bomber Command, 1942-1945. An RAF officer inspects the hole left by a 22,000-lb deep-penetration 'Grand Slam' bomb which pierced the reinforced concrete roof of the German submarine pens at Farge, north of Bremen, Germany. this was the result of a daylight raid mounted by 18 Avro Lancasters of No. 617 Squadron RAF on 27 March 1945, in which two direct hits by 'Grand Slams' caused much of the partially-completed roof to collapse.
context_page_description: The Valentin submarine factory is a protective shelter on the Weser River at the Bremen suburb of Rekum, built to construct German U-boats during World War II. The factory was under construction from 1943 to March 1945 using forced labour, but was damaged by air-raids and unfinished by the end of the war. The Valentin factory was the largest fortified U-boat facility in Germany, and was second only to those built at Brest in France.
  As a manufacturing facility, it differed from conventional U-boat pens, which were designed to house and service operational U-boats.
context_section_description: The Valentin factory was attacked by the RAF on 27 March 1945. The attacking force consisted of twenty Avro Lancaster heavy bombers of 617 Squadron which had, after the "Dambusters" raid, developed precision bombing methods. Simultaneously, a force of 115 Lancasters bombed the nearby fuel oil storage depot in the village of Schwanewede. The bombers were escorted by ninety RAF North American Mustang fighters of 11 Group
  The Lancasters attacking Valentin each carried a single large earthquake bomb – seven carried the 5 ton 'Tallboy', thirteen carried the 10 ton 'Grand Slam'. Two 'Grand Slam's hit the target and penetrated about half-way through the 15-foot (4.6 m) thick ferrous concrete roof before exploding. The explosions blew large holes in the remaining thickness of the roof and brought down around 1,000 tons of debris into the chamber below. Workers who were inside the bunker at the time survived, as the bombs did not penetrate the roof before detonating. Another bomb caused damage to a nearby electricity plant, workshops and a concrete mixing plant.
  Fortunately for the British, the two bombs struck and penetrated the 4.5-metre (15 ft) thick west section of the roof. Post–war American analysis suggested the 7-metre (23 ft) thick, east section would have been able to resist even the Grand Slams, although not without significant damage, and it is unlikely that it would have survived repeated hits.
  Three days later, on 30 March, the US Eighth Air Force attacked Valentin with Disney bombs. These were large (4,500 lb (2,040 kg)) weapons with hard steel casings, rocket-assisted to increase their penetrating power. Sixty were launched but only one hit the target, causing little damage.  However, considerable damage was done to installations surrounding the bunker.
  The factory was abandoned, and four weeks after the bombing, the area was occupied by the British Army's XXX Corps, which captured Bremen after a five-day battle.
caption: An RAF officer examines the crater produced by the March 1945 Grand Slam bomb strike
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