Germany
28 cm/50 (11") SK L/50
Updated 24 November 2012
A slightly more powerful gun than the previous 28 cm SK L/45.  The mountings for these guns used electric pumps to drive hydraulic elevation gear while the training was all electric.  The famous German/Turkish battlecruiser Goeben/Yavuz carried these guns for fifty years.

The battlecruiser Seydlitz has the unfortunate distinction of having her after turrets burned out twice following damage received at the battles of Dogger Bank and Jutland (Skagerrak).  However, alterations and practices put in place following Dogger Bank are credited with saving German lives at Jutland (Skagerrak).

With the exception of Yavuz, during World War II these guns were used only as coastal artillery.  They were then supplied with a lighter shell with a larger propellant charge for increased range.  Four of these guns in single Drh LC/37 coastal turrets were employed as the Grosser Kurfürst battery at Pillau, then at Framzelle, as part of the Channel defenses.

Constructed of A tube, two layers of hoops and a jacket.  Used the Krupp horizontal sliding wedge breech block.  A total of 36 guns were made.

All German 28 cm guns had an actual bore diameter of 28.3 cm (11.1").
WNGER_11-50_skc09_Seydlitz_pic.jpg

Battlecruiser Seydlitz in November 1918
U.S. Naval Historical Center Photograph # NH 45108
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Click here for additional pictures
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Gun Characteristics
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Designation 28 cm/50 (11") SK L/50
Ship Class Used On Moltke and Seydlitz Classes
Date Of Design 1909
Date In Service 1911
Gun Weight
(see Note 1)		 91,491 lbs. (41,500 kg)
Gun Length 557.1 in (14.150 m)
Bore Length 528.4 in (13.421 m)
Rifling Length 445.4 in (11.114 m)
Grooves (80) (2.8 mm D x 6.92 mm W)
Lands (4.2 mm)
Twist Increasing RH 1 in 45 to 1 in 30 at the muzzle
Chamber Volume 9,154 in3 (150 dm3)
Rate Of Fire
(see Notes 2 and 3)		 3 rounds per minute
Notes:

1) The often-seen figure of 149,914 lbs. (68,000 kg) for this weapon actually includes the weight of the Weige (gun cradle).

2) Description from "Naval Weapons of World War Two:"

"The hoists could supply three rounds per gun in 51 seconds, including loading and unloading the hoists, and the firing cycle with a strong and well trained crew was about 20 seconds."
3) During the Dogger Bank battle in 1915 Seydlitz was in continuous action for two hours.  During that time, she averaged a firing rate of one salvo every 42.3 seconds, an impressive performance considering that the guns were hand worked.
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Ammunition
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Type Cartridge - Bag
Projectile Types and Weights World War I
   APC L/3,2 - 666 lbs. (302 kg)

World War II
   APC L/3,2 - 666 lbs. (302 kg)
   HE L/3,6 base fuze - 666 lbs. (302 kg)
   HE L/4,4 base and nose fuze - 626 lbs. (284 kg)
Bursting Charge APC L/3,2 - 19.74 lbs. (8.95 kg)
Others - N/A
Projectile Length APC L/3,2 - about 35.3 in (90 cm)
HE L/3,6 base fuze - about 39.7 in (101 cm)
HE L/4,4 base and nose fuze - about 48.5 in (123 cm)
Propellant Charge World War I
   Main Charge:  174 lbs. (79 kg) RPC/12
   Fore Charge:  57 lbs. (26 kg) RPC/12

World War II
   Main Charge:  154.3 lbs. (70 kg) RPC/32
   Fore Charge:  79.4 lbs. (36 kg) RPC/32

   Total main cartridge weight:  262.3 lbs. (119 kg)
   Silk bag for fore charge:  3.3 lbs. (1.5 kg)

After 1942
   Total:  251.3 - 262.6 lbs. (114 - 119.1 kg) RPC/38 (16/6)
Muzzle Velocity World War I
   2,887 fps (880 mps)

World War II
   2,936 fps (895 mps)
Working Pressure 20.2 tons/in2 (3,180 kg/cm2)
Approximate Barrel Life N/A
Ammunition stowage per gun Moltke:  81 rounds
Seydlitz:  87 rounds
Notes:

1) These guns, like most large caliber German guns of this era, used a "fore charge" which was propellant in a double bag silk case and a "main charge" which was propellant in a brass case.  The brass case helped to seal the breech of the gun.

2) I lack the breakdown between the fore and main charges for the RPC/38 propellants used after 1942.

3) Actual Projectile designations were as follows.

   APC L/3,1 - psgr. L/3,1 (mhb) - I am not entirely certain as to the actual ballistic length of this projectile.  Shape was about 4crh.
   APC L/3,2 - Psgr. L/3,2 (mhb)
   HE L/3,6 base fuze - Spr.gr. L/3,6 Bdz
   HE L/4,4 base and nose fuze - Spr.gr. L/4,4 Bdz u. Kz (mhb)
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Range World War I
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Elevation With 666 lbs. (302 kg) APC L3,1 Shell
Range @ 13.5 degrees
(maximum elevation as built)		 19,790 yards (18,100 m)
Range @ 16.0 degrees
(maximum elevation after 1915)		 Moltke, Seydlitz:  20,890 yards (19,100 m)
Nassau:  22,310 yards (20,400 m)
Range @ 22.5 degrees
(Goeben, only)		 23,730 yards (21,700 m)
Note:  The World War I projectiles are described as "having a rather blunt head," resulting in only a slight increase in range for the higher elevations.
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Range World War II
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Elevation With 666 lbs. (302 kg) APC L3,2 Shell
Range @ 48.1 degrees 33,570 yards (30,700 m)
Elevation With 626 lbs. (284 kg) HE L4,4 Shell
Range @ 49.5 degrees 42,400 yards (38,600 m)
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Armor Penetration
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Elevation With 666 lbs. (302 kg) APC L3,1 Shell
At the Dogger Bank battle in 1915, these guns are credited with penetrating the 5" and 6" (12.7 and 15.2 cm) side armor belts of the British Battle Cruisers.
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Mount / Turret Data
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Designation Two-gun Turrets
   Moltke class (5):  Drh LC/1908
   Seydlitz class (5):  Drh LC/1910

Single Coastal Artillery Turrets
   28 cm L/50 Kst.Drh.L.C/37
Weight  Drh LC/1908:  437.5 tons (444.5 mt)
Drh LC/1910:  (443.5 to 456.7 mt)
Elevation
(see Note 2)		 All as built:  -8 / +13.5
All after 1915:  -5.5 to +16.0 degrees
Goeben:  First increased to +16.0, then to +22.5 degrees

Coastal artillery:   -5 / +50 degrees
Elevation Rate Drh LC/1908:  4 degrees per second
Drh LC/1910:  N/A

Coastal Artillery:  10 degrees per second with shell loaded
Train End Turrets:  About +150 / -150 degrees
Beam Turrets:  About +80 / -80 degrees

Coastal Artillery:  -220 / +220 degrees
Train Rate Drh LC/1908:  3.3 degrees per second
Drh LC/1910:  3.0 degrees per second

Coastal Artillery:  4 degrees per second
Gun recoil
(see Note 3)		 33.1 in (84 cm)
Loading Angle Drh LC/1908:  2 degrees
Drh LC/1910:  2 degrees

Coastal Artillery:  0 degrees
Notes:

1) The guns were individually sleeved but could be coupled together by the elevation gear.  Loading, ramming and the breech mechanism were all hand operated.  Shell rooms were below the magazines with separate lower hoists which ran to a working chamber below the gunhouse.  The upper shell hoists came up between and behind the guns.  Hand worked trays were used to transfer the shells to the loading position where they were rammed by hand.  Cartridges and bags came up near the turret center on the outside of the guns.  Separate slides were used to transfer them to the breech end.  The cartridge was loaded via a manual loading tray, but the fore charge was simply picked up and placed into position.

2) Seydlitz had 62 complete charges ignited during the Dogger Bank battle but there was no explosion.  Following the Dogger Bank action, German mountings were modified to improve flash protection.  Double flap doors were installed at the beginning and end of the cartridge hoists and ready ammunition was removed from the gun houses.  Mountings were modified after Jutland (Skagerrak) to increase the maximum elevation from +13.5 to +16 degrees.  Goeben was modified in 1918 to +22.5 degrees.

3) The recoil distance given above is the nominal figure.  The absolute, metal-to-metal recoil distance was 35.4 inches (90.0 cm).

4) Each turret required 70 men to operate.

5) Magazines were located above the shell rooms.

6) Armor thickness given in "Naval Weapons of World War One" by Norman Friedman:

Drh LC/1908:  N/A

Drh LC/1910
    Face:  9.8 in (25 cm)
    Sides:  7.9 in (20 cm)
    Rear:  8.3 in (21 cm)
    Roof:  2.8 to 3.9 in (7 to 10 cm)
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Data from
"Jutland:  An Analysis of the Fighting" and "Naval Weapons of World War Two" both by John Campbell
"Skagerrak" by Arno Dohm
"Naval Weapons of World War One" by Norman Friedman
"The King's Ships Were at Sea:  The War in the North Sea August 1914 - February 1915" by James Goldrick
"German Warships 1815-1945" by Erich Gröner
"The Big Gun:  Battleship Main Armament 1860-1945" by Peter Hodges
"Battleships of World War I" by Peter Hore
"Die Geschichte der deutschen Schiffsartillerie" by Paul Schmalenbach
"German Battlecruisers 1914-18" and "Battle on the Seven Seas:  German Cruiser Battles 1914 - 1918" both by Gary Staff
"The Ship that Changed the World:  The Escape of the Goeben to the Dardanelles in 1914" by Dan van der Vat
"Admiral von Hipper" by Capt. Hugo von Waldeyer-Hartz
"German Capital Ships of World War Two" by M.J. Whitley
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M.DV.Nr. 234.6, "Vorläufige Beschreibung der 28 cm S.K.L/45, 28 cm S.K.L/50 und 30,5 cm S.K.L/50 in Kst.Drh.L.C.37" Berlin 1941, Oberkommando der Kriegsmarine
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Special help from Peter Lienau
Page History

24 April 2008 - Benchmark
26 August 2011 - Added comment about Seydlitz turret burn-outs, additional projectile information
19 May 2012 - Updated to latest template
24 November 2012 - Added details about guns, ammunition and mountings