The largest RAF Grand Slam Bomb Attack of WWII, on the Valentin Type XXI U-Boat Assembly Plant

In March, 1945 the RAF and 8th Army Air Forces sent their bombers to attack the Valentin Type XXI U-boat assembly building. The attacking munitions includes Grand Slam, Tall Boy, and Disney Swish bombs. This was the largest Grand Slam and Disney Swish missions in WWII. Only one Disney Swish struck the roof. It detonated prematurely and left a small crater in the roof. Two of the Grand Slam bombs struck the facility’s roof and left 30 foot wide full penetration holes. The damage was not as severe in comparison to a bomb which detonated inside the building. None of the 11 soil strikes and near misses damaged the building’s foundation.