10.5 cm SK C/32 naval gun

The 10.5 cm SK C/32 (SK - Schnelladekanone (quick loading cannon) C - Construktionsjahr (year of design) was a German naval gun used in World War II. This was the standard unshielded low-angle deck gun mounted forward of the conning tower in type I, type IX and type X U-boats.  The guns were also used in shielded high-angle mountings aboard type 35 and type 43 minesweepers, Elbing class torpedo boats, cruiser Emden, and old battleships Schlesien and Schleswig-Holstein.

Description
The built-up gun with a barrel, jacket and breech end piece weighed about 1.8 tons. The gun fired a 15.1 kg projectile 105 mm in diameter, and the barrel is sometimes described as 45 caliber. Fixed ammunition (case and projectile handled as a single assembled unit) containing a 4.08 kg propellant charge was 105 cm long. Ceiling was 10300 m at 80° elevation. Useful life expectancy was 4100 effective full charges (EFC) per barrel.

U-boat history
The Ubts LC/32 mounting used in type I and early type IX U-boats weighed about 5 tonnes and could be elevated from -10° to +35°. Later type IX and type XB U-boats used the Ubts LC/36 mounting reducing weight by 10 percent by restricting elevation from -10° to +30°. During the early war years, these guns were used to encourage surrender of independently routed merchant ships or to sink ships damaged by torpedoes. Some of these guns were later removed from U-boats for mounting aboard type 40 minesweepers after unshielded deck guns proved impractical in action against Defensively Equipped Merchant Ships and escorted trade convoys.

Coastal defence gun
Norway used this gun in coastal defence batteries until 2002.

Weapons of comparable role, performance and era

 * QF 4 inch Mk XII & Mk XXII guns : Slightly less powerful British equivalent submarine guns