U-boat Deck Gun

[C.O.Sargent]

Were the deck guns on a U-Boat rifled or smooth bore?
The reason I ask is because with all that sea water it would coroaded pretty quickley.Some people I have talk to have even said they were chrome bored, does anyone know one way or anouther.
I await your answer.

[Spanky]

U-boat deck guns were rifled "cannons," in other words they fired a metallic cased round rather than being charged with separate projectiles and powder charges like a howitzer or large navel gun. The guns were packed in grease between use and required quite a bit of attention and maintenance to remain servicable. I just finished a book by a U-boat officer who fought in the Indian Ocean and participated in handing the boat over to the Japanese after Germany surrendered. He describes an incident where one of the Japanese crewmen accidently discharged the gun during training. He was surprised the barrel did not rupture due to the grease still packed in it.

[C.O.Sargent]

Thanks Spanky:That makes alot of sence did they mention if they put a water prove tarp over the gun?

[Spanky]

A tarp would not have survived well given the very high underwater pressures. Other than grease and maintenance no special consideration was given to the deck gun. They were useful early in the war when surface action was safer. There are numerous records of ships sunk or finished off by gun fire. However as allied air patrols increased in range and effectiveness the U-boats were never safe on the surface and the deck guns were no longer useful.

The late war German Type XXI boats only had a couple of twin 20MM or 30 MM anti aircraft guns and the deck gun was omitted to lessen drag.

All guns, evan AA guns were omitted on post war submarine designs as they were no longer useful and just incresed underwater drag.

[Gordon Williamson]

Here is an original fully restored example in the U-Boot Archiv in Cuxhaven. When at sea as well as being greased the bore was protected by the insertion of a plug into the muzzle to prevent water getting in.