Wa. Pruf 692

This substantial gun bunker was designed by Rudolf Jäger, an Organisation Todt supervisor (hence the alternate name). Following Hitler's request for 10cm artillery to be used for coastal defense in the Channel Islands, vast numbers of captured French 105mm Canon de Mle 1913 were transported to the islands, re-designated to the 10.5cm K331(f). The barrel of the gun was removed from the mobile chassis, and installed in a Fortress mount, the so-called Sockellefette auf Guernseystand. It involved a 1 ton shield which would provide protection against light and medium arms as well as shrapnel. The entire assembly would rotate using a chain-pulley traverse mechanism. In order to accommodate the weapon, the bunker would have a narrow embrasure that provided almost a complete seal against the shield. It was not gas-proof however. A central corridor ran directly from the gun-room entrance to the bunker entrance, intended to be closed at the bunker entrance side using rows of H beams and household bricks, once the elements of the gun had been assembled (this was scarcely done in the Channel Islands). The bunker was constructed often in both a left handed and right handed variant, but they were not complete mirrors of each other, with the foul air extractor always being on the left hand side, and the spent-shell on the right. The bunker also features a crew room, two munitions stores and an entrance defense.