The Anti-aircraft guns At the beginning of the war the standard
U-boat anti-aircraft (AA) weapon was a single 2cm gun. The
Germans knew these as Flak from Flugabwehrkanone. The 2cm gun
was most often the C/30 version in LC 30/37 mountings. From 1941
the 3,7cm gun SK C/30U became standard on type IX boats. More
power added to the AA defences In 1939 and 1940 the weapon was
located aft of the tower and it served its purpose up to a
point. But it was quickly apparent that this was no an effective
defence. In the following years the conning tower (Germ.
Turmumbau) was rebuilt several times for better AA defence.
There was widening of the bridge to put on two double-barrelled
13,2mm Breda-Fla-MG and one traditional 2cm gun. That version
was mainly used on the Mediterranean-boats from autumn 1942 to
autumn 1943. Below you see U-81 with this layout. Now two 2cm
C/38 were fitted on bridge and on the additional platform which
became known as the Wintergarten. The Turmumbau II was only an
interim solution and was first