The Škoda Works of Pilsen produced a total of 65 guns (5 of them were spares). The first 13 were for the Radetzky-class, the second 52 were for the Tegetthoff-class. Only the second series, the guns for the Tegetthoff-class, were designated as K10. The K10 differed slightly from the earlier 30.5 (12") guns in that its chamber was 1.97 inches (5 cm) longer, so that it could handle a heavier propellant charge.
Erzherog Franz Ferdinand, Radetzky and Tegetthoff were ceded after World War I to Italy, where they were scrapped and their guns then used as coastal artillery.
Actual bore diameter was 30.50 cm (12.008 inches).
Stern Mounts of Viribus Unitis
Breech of one of the 30.5 cm guns on Prinz
Painting of Viribus Unitis
|Designation||30.5 cm/45 (12") K10|
|Ship Class Used On||Austria-Hungary: Radetzky and Viribus
Italy: Coastal Artillery
|Date Of Design||1910|
|Date In Service||1911|
|Gun Weight||116,070 lbs. (52,650 kg)|
|Gun Length oa||541 in (13.750 m)|
|Bore Length||about 512 in (14.461 m)|
|Rate Of Fire||3 rounds in first minute, 1 to 2 rounds per minute afterwards|
|Projectile Types and Weights||Austria-Hungary: AP - 992 lbs. (450
Italy: AP - 997 lbs. (452 kg)
|Propellant Charge||Austria-Hungary: N/A
Italy: 304 lbs. (138 kg)
|Muzzle Velocity for AP||Austria-Hungary: 2,625 fps (800
Italy: 2,510 fps (765 mps)
|Working Pressure||18.4 tons/in2 (2,900 kg/cm2)|
|Approximate Barrel Life||N/A|
|Ammunition stowage per gun||Radetzky: N/A
Viribus Unitis: 76 rounds
|Note: The figures for Italian service are an assumption based upon notes in "Naval Weapons of World War Two" by John Campbell.|
|Elevation||With Austria-Hungary 992 lbs. (450 kg) AP Shell||With Italy 997 lbs. (452 kg) AP Shell|
|Range @ 20 degrees||about 21,870 yards (20,000 m)||N/A|
|Weight||620 tons (630 mt)|
|Elevation||-3 / +20 degrees|
|Elevation Rate||2.5 degrees per second|
|Train||+140 / -140 degrees|
|Train Rate||3 degrees per second|
|Gun recoil||33.5 inches (85 cm)|
|Loading Angle||+2 degrees|
1) These turrets were poorly protected with thin armor. There was an unprotected slot between the gunhouse and the barbette. The cupolas for the rangefinders on the turret roofs were overly large. A hit on one of these could have peeled back the thin turret roof armor.
2) Under battle conditions the gun houses could not be ventilated as they would have sucked in the propellant gasses. It was estimated that they had no more than 15 minutes of oxygen once the ventilation was shut down.
3) On the Viribus Unitis class the heavy weight of the superimposed turrets caused hull distortions, requiring stiffening of the longitudinal frames.
Unitis - Austro-Hungarian Battleships
27 November 2007 - Benchmark
18 July 2010 - Updated with information supplied by Mihály Krámli