After Fall Gelb, which is the German designation for the invasion of the Netherlands and Belgium in May 1940, the Kriegsmarine took hold of IJmuiden and captured the Dutch defences of the coast, the IJmuiden harbour, the Port of Amsterdam and the North Sea Canal leading to industry and a ship lock.
The Dutch Army had already built some defensive strongpoints to protect their assets which made a good start for the Kriegsmarine. They started to lift the defensives to the Atlantic Wall standards with better coastal guns, anti aircraft positions, mine field on land and in the sea, radar posts, anti tank barriers and so on. Besides the defensive measures they ordered offensive installations to the ‘Festung IJmuiden’ in late 1940. They ordered a bunker to harbour for the fast Schnellboot or torpedo boats and the mine laying Raumboot. The latter was also called R-boot and like the name refers to it means a spacious boat, it could load a lot of stuff, commonly mines but other goods as well.
The Kriegsmarine wanted a Schnellbootbunker in the port of IJmuiden and Organistion Todt received the order. Named after the founder Fritz Todt this organisation constructed lots of bunkers and buildings requested by the Third Reich. They build a torpedobunker close to the first Schnellboot bunker thay added a railroad to supply the fast attack boats with the torpedo’s.
The torpedo bunker and the first Schnellboot bunker were finished in 1941. The Torpedo bunker had wall of 2,5 metres thick and a roof of 3 metres thick. Above the door were heavy concrete slabs that could be lowered in case of need. The First Schnellboot bunker got the designation ‘AY’ and had walls made of forced concrete, 1,20 metres thick and a roof of 2,20 metres thick. It could harbour 10 fast attack boats, also called S or E-boats.
In 1942 construction started on a second Schnellboot bunker named ‘BY’. Even bigger than the first it would hold 14 boats and had 4 repair docks. It had concrete fuel depots and a double floating bombproof roof. Under this roof a 1000 men personnel could find shelter. Measurements of this huge bunker are; 242 metres long, 74 metres wide and 18 high (794 feet by 243 feet – 60 feet heigh). The genuine bunker roof, under the floating roof, was 5 metres thick, walls were 4 metres thick. Construction stopped earlier than planned, for the original wide of Schnellbootbunker was 98 metres (322 feet) so they stopped 24 metres early. The walls sloped a bit so that bombs would bounce off when hitting the side of the bunker.
Late 1940 when the construction on these bunkers started the RAF flew three sorties a week above the northern part of the Netherlands. Of course the bunkers were notices and the allied had learned the power of the fast hit and run boats from the Kriegsmarine over time during the war. In 1944 they decided to bomb the bunkers and try to take them out of commission.
On August the 24th the Schnellboot bunker AY, the first constructed Schnell boat bunker, was a target for an allied air attack for the first time. Multiple air raids would in 1944 and in 1945. The Allies used some new developed bunker buster bomb like the Tall Boy and the Disney Bomb. The Schnellboot bunker one or ‘AY’was hit and left unusable, it was never repaired after the attack that demolished it.
The TallBoy was a 5000 kilogram bomb and was dropped from 6 kilometres height, so it would hit the object with the speed of sound. First it would penetrate the bunker and then explode inside. Originally it was planned with a weight of 10.000 kilogram but there was not a plane developed that could carry it in 1944.
The Disney bomb was a rocket shaped slender long bomb with solid rocket fuel propulsion and about 2000 kilograms heavy. After the drop from the bomber plane the engine would ignite at 1,5 kilometres height and gain more speed to penetrate the bunker roof. About 5 metres of forced concrete could be penetrated with the Disney Bomb. During the assault on the Schnell boat bunkers the Disney bomb was not as effective as hoped on the second bunker, it penetrated the upper roof but failed to pierce the lower, 5 metres, roof.
Schnellboot bunker one was demolished in 1947, only a part of the foundation can be found today. The Torpedo bunker is in use by all kind of musical bands. The Schnellboot bunker 2 is one of the biggest bunkers on Dutch soil from World War Two and is not freely accessible. A company runs the bunker these days and uses it for storage of materials and goods. Some bomb damage can still be clearly seen at the bunker.