Hi Jamie,

At the beginning of the war the single barrel 20mm AA guns were kept in a pressure proof container secured to the deck or recessed into it. That quickly proved to be unworkable. There wasn’t time to assemble the gun when the boat surfaced and there certainly wasn’t time to disassemble it & store it during an emergency dive. On the larger U-boats an area was added at he read of the conning tower called the winter garden and the guns were mounted on it permanently. Later as the AA guns got bigger it would not have been possible to keep them inside and bring them up when needed. There were twin 20mm guns, a single barreled 37mm gun, a twin 37mm and a quad 20mm gun and none were kept inside the boat they were just left to the elements & salt water. They malfunctioned frequently as a result too.

A few boats had heavy machine guns in canisters on the winter garden. The guns were spring loaded and popped out of the canisters as soon as they were opened so there was little setup required.

There were also ordinary light belt fed or drum fed machine guns (roughly 30 cal.) that were kept inside the boat and brought up when the boat surfaced that were used against aircraft.

There were generally “ready use” ammo lockers recessed in the deck close to the AA guns and additional ammo was brought up from inside the boat as necessary.

The configuration of the winter gardens changed over the course of the war. Some had only one & other had two etc. and the size & shape also changed. The small Type II boats mounted their guns a bit differently than the larger & more common Type VII & Type IX (like U-505).

You got mail.

Regards,

Ken Dunn