Germany
10.5 cm/65 (4.1") SK C/33
Updated 29 March 2013
This weapon was used primarily as AAA on cruisers and capital ships, although it could be used against surface targets.  A reasonably good weapon, but its training and elevation rates were rather slow.  Replaced the older 8.8 cm (3.5") SK C/31 on newer ships.

Note the triaxial mounting in the picture below.  This was intended to be able to compensate for the motion of the ship and so maintain target lock.  Unfortunately, this mounting proved to be susceptible to electrical faults as it was not sufficiently waterproofed and the mountings were opened to the weather.  These earlier mounts had limited RPC.  The "H" class battleships were to have much improved enclosed mounts with full RPC, but these ships were never completed.

An interesting post-war usage of these guns was on the French destroyers Guichen and Châteaurenault.  These were the former Italian light cruisers Scipione Africano and Atilio Regolo which were ceded to France in 1948.  All of their Italian armament was removed and they were rearmed with six German 10.5 cm/65 guns and ten French 57 mm/60 AA guns.

Earlier guns were of loose barrel construction, but later guns designated as SK C/33 na had a two-piece barrel with a heavier jacket and were considerably lighter.  A late war design that was designated as SK C/33 nT had the two pieces redesigned as a forward loose muzzle piece and the rear part as a short loose liner.
WNGER_41-65_skc33_pic.jpg

10.5 cm/65 SK C/33 Twin Mounting showing the triaxial motion
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Click here for additional pictures
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Gun Characteristics
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Designation 10.5 cm/65 (4.1") SK C/33
10.5 cm/65 (4.1") SK C/33 na
10.5 cm/65 (4.1") SK C/33 nT
Ship Class Used On Germany
   Capital Ships and Cruisers:  Deutschland, Scharnhorst, Bismarck, Admiral Hipper and Prinz Eugen classes
   U-Boat Depot Ships:  Bauer class
   S-Boat Depot Ships:  Lüderitz and Nachtigal classes as rearmed
   Planned for "H" class battleships, Graf Zeppelin class and Seydlitz aircraft carriers

France:  Guichen and Châteaurenault
Date Of Design 1933
Date In Service 1935
Gun Weight
(see Note)		 SK C/33:  10,053 lbs. (4,560 kg)
SK C/33 na:  9,336 lbs: (4,237 kg)
SK C/33 nT:  N/A
Gun Length oa 269 in (6.84 m)
Bore Length 249.9 in (6.348 m)
Rifling Length 217.8 in (5.531 m)
Grooves (36) 0.051 in deep x 0.2165 in (1.3 mm x 5.5 mm)
Lands 0.144 in (3.66 mm)
Twist Increasing RH 1 in 55 to 1 in 35
Chamber Volume 446 in3 (7.31 dm3)
Rate Of Fire 15 - 18 rounds per minute
Note:  The earlier loose-barrel weighed 2,370 lbs. (1,075 kg) while the later two-piece barrel for the na weighed 1,653 lbs. (750 kg).
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Ammunition
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Type Fixed
Weight of Complete Round HE - 58.4 lbs. (26.5 kg) (with RPC/32)
HE - 60.3 lbs. (27.35 kg) (with RPC/40)
HE, Incendiary - 51.8 lbs. (23.5 kg)
Projectile Types and Weights HE - 33.3 lbs. (15.1 kg)
AP - 34.8 lbs. (15.8 kg)
HE, Incendiary - 34.8 lbs. (15.8 kg)
Illum - 32.4 lbs. (14.7 kg)
Bursting Charge N/A
Projectile Length HE - 18.1 in (45.9 cm)
HE, Incendiary - 17.2 in (43.8 cm)
HE Complete Round - 45.83 in (116.4 cm)
HE, Incendiary Complete Round - 44.96 in (114.2 cm)
Propellant Charge
(see Note 4)		 11.46 lbs. (5.2 kg) RPC/32
13.34 lbs. (6.05 kg) RPC/40N
Muzzle Velocity HE - 2,952 fps (900 mps)
AP - N/A
Illum - 2,133 fps (650 mps)
Working Pressure 18 tons/in2 (2,850 kg/cm2)
Approximate Barrel Life 2,950 rounds
Ammunition stowage per gun
(see Note 2)		 Scharnhorst, Bismarck, "H", Graf Zeppelin:  400 rounds
Adm. Graf Spee:  400 - 500 rounds
Admiral Hipper and Prinz Eugen:  420 rounds
Notes:

1) The above Barrel Life figure is from "German Capital Ships of World War Two."  "Battleships:  Axis and Neutral Battleships in World War II" credit this weapon with a life of 4,100 rounds.  It is possible that these different values are for different mods of this weapon.

2) These are the design figures.  "German Warships 1815-1945" says that the actual outfit for Bismarck was 420 rounds and that for Admiral Hipper was 400 rounds.

3) Outfit for warships was HE and HE incendiary, both nose and base fuzed and with or without tracer and illumination.  Depot ships included AP rounds in their outfits, but this was rarely carried by warships.

4) As originally introduced, cartridges for these weapons used RPC/32 propellant.  RPC/40N was the most common propellant used during World War II.
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Range
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Elevation With 33.3 lbs. (15.1 kg) HE Shell
Range @ 45 degrees 19,357 yards (17,700 m)
AA Ceiling @ 80 degrees 41,010 feet (12,500 m)
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Mount / Turret Data
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Designation
(see Note 6)		 Twin Mounts
   Scharnhorst (7), Lützow (3), Admiral Hipper (6) and Prinz Eugen (6):  Dop. L. C/31
   Bismarck:
      Forward mountings (4):  Dop. L. C/31
      Aft mountings (4):  Dop. L. C/37
   Tirpitz
      Forward mountings (6):  Dop L. C/37
      Aft mountings (2):  Dop L. C/31
   Graf Zeppelin (4), Seydlitz (5 - as aircraft carrier), Bauer (1), Lüderitz (1) and Nachtigal (1):  Dop. L. C/37
   "H" (8):  Dop. L. C/38

   Guichen (3) and Châteaurenault (3):  Dop. L. C/37
Weight  Dop. L. C/31:  61,300 lbs. (27,805 kg)
Dop. L. C/37:  59,646 lbs. (27,055 kg)
Dop. L. C/38:  about 97,000 lbs. (44,000 kg)
Elevation C/31:  -8 / +80 degrees
C/37 and C/38:  -10 / +80 degrees
Elevation Rate Dop. L. C/31:  10 degrees per second
Dop. L. C/37 and C/38:  12 degrees per second
Train 360 degrees
Train Rate Dop. L. C/31:  8.0 degrees per second
Dop. L. C/37:  8.5 degrees per second
Dop. L. C/38:  10 degrees per second (20 degrees per second slew speed)
Cross Leveling - 17 / +17 degrees
Cross Leveling Rate Dop. L. C/31:  5 degrees per second
Dop. L. C/37:  8 degrees per second
Dop. L. C/38:  10 degrees per second
Recoil Dop. L. C/31:  16.1 in (41 cm) max
Dop. L. C/37:  15.0 in (38 cm) max
Dop. L. C/38:  15.7 in (40 cm) max
Notes:

1) "Battleships:  Axis and Neutral Battleships in World War II" credits the C/37 and C/38 mounts with -15 / +85 degrees elevation.

2) The Dop. L. C/31 was originally developed for the 8.8 cm AA gun used on earlier ships.  This mounting was then adapted for use with 10.5 cm guns.  This can be distinguished from the later Dop. L. C/37 by its shorter shield.

3) Twin mounts had a crew of six on-mount plus ammunition passers.

4) The guns in the L. C/31 and L. C/37 mountings were in separate cradles.  Both mountings were trained via electrically driven hydraulic gear while the elevation and cross-leveling gear were all electric.  Elevation was partially RPC and the cross-leveling was fully RPC.  The loading gear used an electric motor on the cradle to drive a continuously running roller above the bore with an idler roller in the breech block.  These helped to ram the round into the breech.  L. C/37 had a fuze setter for each gun mounted near the breech.

5) The Dop. L. C/38 was an all-electric true turret with full RPC and was to have hoists on the outside of each gun supplying rounds horizontally with automatic loading.  One long trunk and one short trunk prototype were completed for evaluation, but the production units were cancelled along with the "H" class battleships.

6) The mixing of Dop. L/31 and Dop. L./37 mountings on Bismarck may partially account for her poor showing against British aircraft during her only operational sortie.  These mounts had different training and elevating characteristics that were apparently not accounted for in her AA fire control systems.  Tirpitz was originally fitted with two Dop. L/31 mounts but these were replaced in late 1941 giving her a uniform battery of eight Dop. L/37 mounts.  The Kriegsmarine designated these mountings in their standard fashion for secondaries with starboard mountings being Stb I (forward) through Stb IV (aft) and port mountings being Bb I (forward) through Bb IV (aft).

7)  Distance between gun axes:
        Dop. L. C/31:  26.8 in (68 cm)
        Dop. L. C/37:  26.0 in (66 cm)
        Dop. L. C/38:  38.2 in (97 cm)

8) Bismarck and Tirpitz were equipped with a practice gun installed between "C" and "D" turrets.  This consisted of a complete breech mechanism and a short barrel.
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Data from
"Naval Weapons of World War Two" by John Campbell
"The Postwar Naval Revolution" by Norman Friedman
"Battleships:  Axis and Neutral Battleships in World War II" by W.H. Garzke, Jr. and R.O. Dulin, Jr.
"German Warships 1815-1945" by Erich Gröner
"French Cruisers:  1922 - 1956" by John Jordan and Jean Moulin
"German Naval Guns:  1939 - 1945" by Miroslaw Skwiot
"German Capital Ships of World War Two" and "German Cruisers of World War Two" both by M.J. Whitley
"Warship Pictorial #21:  Kriegsmarine Prinz Eugen" by Steve Wiper
Page History

10 September 2007 - Benchmark
26 January 2009 - Added gun information and ship usage
17 February 2010 - Corrected number of mountings on Scharnhorst, miscellaneous changes
05 June 2011 - Updated data for Tirpitz mountings and added note about practice gun
29 March 2013 - Added information about Châteaurenault