During World War II these guns were used as coastal artillery. They were then supplied with a better ballistically shaped shell and with a larger propellant charge for increased range.
Constructed of A tube, two layers of hoops and a jacket. Used the Krupp horizontal sliding wedge breech block. About 16 guns were made.
Actual bore diameter was 20.93 cm (8.24").
Blücher as she appeared pre-war as
a gunnery training ship
One of the wing turrets on SMS Blücher
|Designation||21 cm/45 (8.27") SK L/45|
|Ship Class Used On||Blücher|
|Date Of Design||about 1905|
|Date In Service||1909|
|Gun Weight||16,156 lbs. (16,400 kg)|
|Gun Length oa||370.9 in (9.420 m)|
|Bore Length||347.5 in (8.826 m)|
|Rifling Length||292.5 in (7.430 m)|
|Grooves||(60) 0.79 in D x 0.266 in W (2.0 mm D x 6.76 mm W)|
|Lands||0.165 in (4.2 mm)|
|Twist||Increasing RH 1 in 45 to 1 in 30 at the muzzle|
|Chamber Volume||3,033 in3 (49.7 dm3)|
|Rate Of Fire||4 - 6 rounds per minute|
|Projectile Types and Weights||World War I
AP L/3,1 - 238 lbs. (108 kg)
HE L/3,1 - 238 lbs. (108 kg)
World War II
|Bursting Charge||AP L/3,1 - 7.67 lbs. (3.5 kg)
HE L/3,1 - 15.18 lbs. (6.9 kg)
Others - N/A
|Projectile Length||AP L/3,1 - 25.6 in (65 cm)
HE L/3,1 - 25.6 in (65 cm)
HE L/4,3 - 35.5 in (90 cm)
(see Note 3)
|World War I
77.3 lbs. (35.1 kg) RP C/06
World War II
|Cartridge Case Type, Size and Empty Weight||Brass, 210 x 836 mm, N/A|
|Muzzle Velocity||2,953 fps (900 mps)|
|Working Pressure||20.2 tons/in2 (3,175 kg/cm2)|
|Approximate Barrel Life||N/A|
|Ammunition stowage per gun||85 rounds|
1) The World War II HE round was a special coastal artillery projectile with both base and nose fuzes. This projectile was of better ballistic shape than the earlier AP projectile.
2) Actual Projectile designations were
3) 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. I lack the breakdown of the propellant weights between the fore and main charges.
|Range @ 30 degrees
(Max. elevation of turret)
|Range @ 45 degrees
Blücher (6): DrL C/06
|Weight||195 to 197 tons (198 to 200 mt)|
|Elevation||-5 / +30 degrees|
|Elevation Rate||4 degrees per second|
|Train||Forward and Aft Turrets: about -150
/ +150 degrees
Beam Turrets: about +30 / +150 degrees
|Train Rate||3.5 degrees per second|
|Gun recoil||20.5 in (52 cm)|
1) All but the forward wing turrets fed from common projectile/propellant ammunition magazines with two fixed hoists passing projectiles and main charges to a handling room below the gunhouse. Upper hoists revolved with the gunhouse. Each gun had a single hoist which fed both projectiles and main charges to the gun while the fore charge was supplied by auxiliary hoists located between the main hoists. The working chamber held ready ammunition, storing either 38 APC or 34 HE, 26 main and 52 fore charges. These allowed the guns to fire at about six rounds per minute until these were used up and then about 4 to 5 rounds per minute afterwards.
2) Forward wing turrets differed from the other turrets in that they were fed from a combined magazine located beneath the rear wing turret via a centerline conveyor belt. This fed the turret handling rooms via inclined hoists, one for projectiles and one for main charges. Fore charges were passed into the handling room through openings in the barbette.
3) Gun axes were 70.9 in (180 cm) apart.
4) Armor thickness given in "Naval Weapons of World War One" by Norman Friedman:
Face: 7.1 in (18
29 February 2008 - Benchmark
28 March 2010 - Added side view of Blücher
22 May 2012 - Updated to latest template
25 November 2012 - Added details about guns, ammunition and mountings