[Raven_2012]

Yeah I kind of figured they would have to be fitted on larger u-boats. The decks needed to be able to handle them. I never really used them much, I have much luck with 88mm. Then again I haven't played much of the game in past to get later in campaign to where I need to use them.

Originally Posted by gap

For the record, the 10.5 cm SK C/32 was the standard deck gun issue for Type I, IX and X U-boats. The gun entered service in 1934, and it was also used on T1 and T22 Torpedo Boats, F-boats, some 1940 Type minesweepers, and aboard the Emden light cruiser and Deutschland class battleships as refitted in 1944.

I doubt that Type VII U-boats were ever (re)fitted with any deck gun heavier/bulkier than the common 88mm. On the contrary, standard deck guns being removed from Atlantic boats starting from June 1943, is a well documented fact.

sources:
http://www.navweaps.com/Weapons/WNGER_41-45_skc32.htm
http://en.wikipedia.org/wiki/10.5_cm_SK_C/32_naval_gun
http://www.uboataces.com/weapon-deck-gun.shtml
http://uboat.net/technical/guns.htm