Germany 30.5 cm/50 (12") SK L/50 (2024)

These guns were fitted to many battleships and battlecruisers completed just before and after the start of World War I. When compared to contemporary British guns in terms of penetrating power, they were superior to the 12"/45 (30.5 cm) and 12"/50 (30.5 cm) guns, and only slightly less powerful than the 13.5" (34.3 cm) guns. They were, of course, completely outclassed by the 15"/42 (38.1 cm) guns used on the Queen Elizabeth class.

The battlecruisers Derfflinger and Lützow used these weapons at the Battle of Jutland (Skagerrak) to sink the British battlecruisers HMS Queen Mary and HMS Invincible.

The World War I Coastal Defense Battery Kaiser Wilhelm II located near Knocke in Belgium was equipped with four of these guns.

The mountings for these guns used electric pumps to drive hydraulic elevation gear while the training was all electric. These guns also had hydraulically worked rammers and breeches, the first fitted to German large-caliber guns. These changes increased the rate of fire, with most ships having a ROF of 20 seconds while the Kaiser class were reported to have had an overall ammunition supply speed of three rounds in 48 seconds, including all transfers.

In World War II these guns were used only as coastal artillery. They were then supplied with a more streamlined shell and used a larger propellant charge, giving them increased range. The best known battery was the six-gun Friedrich August at Wangerooge. Later, three of these guns on BSG mountings were moved to near Wimille on the Channel Coast.

Constructed from shrunk on tubes and hoops and used the Krupp horizontal sliding wedge breech block.

Actual bore diameter was 30.50 cm (12.008").

• ^The often-seen figure of 171,079 lbs. (77,600 kg) for this weapon actually includes the weight of the Weige (gun cradle).

• ^

  Actual designations for World War I Projectiles

  APC L/3,4	30,5 cm Psgr. L/3,4
  HE L/3,8 base fuze	30,5 cm Spgr. L/3,8 Bdz
  HE L/5,3 base fuze	30,5 cm Spgr. L/5,3 Bdz

  Actual designations for World War II Projectiles

  APC L/3,4	30,5 cm Psgr. L/3,4
  HE L/3,8 base fuze	30,5 cm Spgr. L/3,8 Bdz
  HE L/3,6 base and nose fuze	30,5 cm Spgr. L/3,6 Bdz u. Kz (m.Hb)

• ^A Note on Sources: Weights for both the APC L/3,4 and for the HE L/3,8 vary in many references. I have chosen to use the weight given in both M.Dv. Nr. 170,54 and in M.Dv. Nr. 234,6 and as stenciled on the projectiles shown in these documents which are all given as 405.0 kg (892.9 lbs.).

• ^A Note on Sources: Many English language references show the designation for the Psgr. (APC) projectile with a "(m.Hb)" suffix (projectile with ballistic cap). However, this suffix is not used in any German documentation for this projectile that I have found.

• ^A Note on Sources: In "Jutland: An Analysis of the Fighting" by John Campbell the length of the World War I 30,5 cm Psgr. (APC) is given as 97.4 cm (38.3 inches) or about L/3,1. However, the sketch used to illustrate this projectile is identical to the one in the World War II German document M.Dv. Nr. 170,54 where it is identified as the 30,5 cm Psgr. L/3,4. While no overall projectile length is given in the German documents, scaling it using a dimension that is on the sketch shown below has found that this projectile was about 3.4 calibers in overall length. More recent publications such as "German Battlecruisers of World War One" by Staff only note the Psgr. L/3,4 and not a L/3,1. From this analysis, I believe that the World War I and the World War II Psgr. projectiles were most likely the same shell and that Campbell is likely incorrect.

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• ^A Note on Sources: In "German Battlecruisers of World War One" the weight of the Spgr. L/3,8 Bdz (HE L/3,8 base fuze) is stated as being 415 kg (915 lbs.) which is incorrect. See "A Note on Sources" below regarding 405.0 kg and 415 kg projectiles.

• ^The HE L/5,3 projectile was the HE L/3,8 base fuze projectile modified to add a ballistic cap.

• ^A Note on Sources: M.Dv. Nr. 198, first issued in 1940 and updated a few times until 1944, lists that the 30,5 cm SK L/50 gun had two 405 kg (892.8 lbs.) projectiles - 30,5 Psgr. L/3,4 and 30,5 cm Spgr. 3,8 Bdz, both introduced before World War I - and three 415 kg (915 lbs.) projectiles - 30,5 cm Psgr. L/4,9 (m.Hb), 30,5 cm Spgr. L/5 Bdz. (m.Hb) and 30,5 cm Spgr. L/4,8 Kz. (m.Hb). This may be the source used by the post-war "Service Major Caliber Projectiles of the German Navy: Technical Report No. 393-45" which lists all five of these projectiles as being for the 30,5 cm SK L/50 gun. Neither of these works mentions the prototype 30,5 cm SK C/39 gun found in "Naval Weapons of World War Two." As its designation implies, this prototype gun was designed in 1939 and completed shortly afterwards. This book does not mention the 405 kg (892.8 lbs.) projectiles at all, but instead states that 415 kg (915 lbs.) projectiles were used for both the 30,5 cm SK L/50 guns and also for the prototype 30,5 cm SK C/39 gun. In reviewing German primary source documents, it is found that 415 kg (915 lbs.) projectiles are not listed in two Kriegsmarine documents for the 30,5 cm SK L/50 guns; M.Dv. Nr. 170,54, which was issued in 1940, and M.Dv. Nr. 234,6, which was issued in 1941. In addition, respected English language books for these guns such as "German Artillery of World War Two," published in 1975, also do not list the 415 kg (915 lbs.) projectiles but instead list the 405 kg (892.8 lbs.) projectiles as being issued for this weapon. Finally, in examining the 415 kg (915 lbs.) projectile types listed in M.Dv. Nr. 198, it seems obvious that they are 'German ship type' projectiles, not 'German coastal artillery type' projectiles, which were usually low weight types in order to obtain the maximum range possible. In trying to resolve these discrepancies and weighing alternatives, what seems to be the most reasonable answer is that these heavier projectiles were actually developed for the prototype 30,5 cm SK C/39 gun which was intended to arm a new class of commerce-raiding heavy cruisers. They may have been test fired by the older 30,5 cm SK L/50 gun on the proving grounds, but probably were not actually introduced into service for that weapon. Based upon this conclusion, the 415 kg (915 lbs.) projectiles are listed only on the datapage for the 30,5 cm SK C/39 gun and not on this datapage.

• ^German HE Base and Nose Fuzed projectiles with ballistic caps had a rod between the nose of the shell and the fuze to improve performance when striking obliquely. See details on 12.7 cm SK C/34 datapage.

• ^Burster weights (reiner Sprengstoff) for World War I projectiles mainly from "Diagrams of Great War."

• ^The APC burster had a wooden block in the nose of the burster cavity which acted as a shock absorber.

• ^A Note on Sources: In "Jutland: An Analysis of the Fighting" by John Campbell, the APC L/3,4 burster weight is given as 30 lbs. (13.61 kg). I believe that this weight is too heavy and that the actual weight was probably closer to the 23.78 lbs. (10.785 kg) of the World War II loading. "Naval Weapons of World War One" says the burster was 25.0 lbs. (11.34 kg), but apparently uses the explosive and non-explosive weight (Gesamtgewicht) which was 25.39 lbs. (11.518 kg) rather than the actual explosive weight (reiner Sprengstoff) of 23.78 lbs. (10.785 kg).

• ^12.112.2As noted above, the HE L/5,3 base fuze projectile was the HE L/3,8 base fuze projectile modified with a long ballistic cap. The burster was the same in both projectiles and there was a wooden block in the nose of the burster cavity which acted as a shock absorber.

• ^Burster weights (reiner Sprengstoff) for World War II projectiles from M.Dv. Nr. 170,54.

• ^The burster for the APC L3,4 projectile of World War II was made from Fp 15 and Fp 1.

• ^The burster for the HE L/3,8 base fuze projectile of World War II was made from Fp 15, Fp 10, Fp 5 and Fp 1.

• ^The burster of the HE L/3,6 base and nose fuze projectile of World War II was made entirely with Fp 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 "rear charge" which was propellant in a brass case. The brass case helped to seal the breech of the gun.

• ^Propellant weights differ in many references and even in official documents such as the M.Dv. Nr. 170 and M.Dv. Nr. 190 series. This seems to be the result of most charges being listed as "zu etwa" which means "to about." This was probably because the different propellant formulations used - such as C/32 or C/38 - varied in weight. In addition, different loading weights were used depending upon the powder grain size utilized to make up the charge. The weights in the table above are for the powder grain specified.

• ^Firing with reduced charges usually did not use a forward charge. Reduced charges were made with RP C/06, apparently to use up existing stocks of the older propellant.

• ^The silk bag for the fore charge weighed 5.3 lbs. (2.4 kg).

• ^Using the "Small Battle Load" of just the rear charge gave a muzzle velocity of about 2,034 fps (620 mps).

• ^The cartridge rim diameter was 350.2 mm.

• ^Outfits were typically 70% APC and 30% HE.

• ^British post-war documents state that the Kaiser class carried 98 to 103 rounds per gun.

• ^British post-war documents state that the König class carried 96 to 100 rounds per gun.

• ^Outfit for Derfflinger class was 65 APC and 25 HE per gun.

• Diagrams of some of these projectiles and their fuzes and propellant charges may be found below.

The HE L/3,8 base fuze projectiles were stated to be capable of penetrating 2 to 6 meters (6 to 20 feet) through unarmored structures before detonating.

• ^The Kaiser class were the first German battleships to have superfiring turrets. This allowed them to have one less turret than previous classes (5 vs. 6) yet still be able to fire the same number of guns on the broadside.

• ^The König class had all main guns on the centerline, giving them a heavier broadside than earlier ships.

• ^Derfflinger had a crew of 70 men in C mounting and probably in A and B as well while D mounting had 80 crewmen.

• ^The mounting weight differences were mainly the result of thicker armor used on the battleships.

• ^

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

  	Battleships	Battlecruisers
  Face	11.8 in (30 cm)	10.6 in (27 cm)
  Sides	9.8 (25 cm)	8.7 in (22 cm)
  Rear	11.4 in (29 cm) except Kaiser class: 10.6 in (27 cm)	10.6 in (27 cm)
  Roof	3.1 to 4.3 in (8 to 11 cm) except Helgoland class: 2.8 3.9 in (7 to 10 cm)	3.1 to 4.3 in (8 to 11 cm) except Hindenburg: 3.1 to 5.9 in (8 to 15 cm)

• ^Prinzregent Luitpold was modified just before and the other ships shortly after Jutland (Skagerrak) to increase the maximum elevation from +13.5 to +16.0 degrees. A few sources claim that the maximum elevation was increased on all ships to 16.5 degrees rather than to 16.0 degrees. Norman Friedman in "Naval Weapons of World War One" gives conflicting data for maximum elevations and ranges with no explanation. For that reason, I do not believe this source to be a reliable reference in this matter.

• ^The recoil distance given above is the nominal figure. The absolute,metal-to-metal recoil distance was 38.6 inches (98.0 cm).

• Run out was by compressed air. Magazines were below shell rooms on the battleships.

• On the Derfflinger class except for Hindenburg, A, B and C turrets had the magazines below the shell rooms, but D turret had the magazine above the shell room for reasons of space. D turret also did not have the shell hoists broken at the working chamber as did all other 30.5 cm (12") mountings. Instead, the projectile hoist ran directly from the shell room up to the gunhouse. Hindenburg had all shell rooms below the magazines as in the battleships. Hindenburg also differed from her half-sisters by having LC/1913 mountings with half the number of hoists as the the LC/1912, but these hoists ran faster and were still capable of supplying the equivalent of three complete rounds per gun per minute. The LC/1913 turrets had 7.7 m (25.5 foot) rangefinders on each turret rather than 3 m (10 foot) rangefinders on earlier designs. The Helgoland, Kaiser and König classes had a machinery level directly below the gunhouse with a handling room below it. Lower shell and projectile hoists came up to this room and the ammunition was then transferred over to upper hoists which ran up to the gunhouse. Battlecruisers were similar except for Hindenburg in which the projectile hoists ran directly up to the gunhouse although the propellant hoists were still two-stage.

• Training of the gun turrets was electric and gun elevation was hydraulic. Hydraulic power was provided by two electrically-driven triple pumps. Rammers were hydraulically powered with fluid being supplied directly from the elevation pump. Wedge breech mechanisms were hydraulically powered but could be manually operated.

• Propellant smoke was removed with two independent suction systems, each with its own motor. Should one motor fail, the other motor could be coupled to run both systems at a reduced rate.

• For at least the Drh LC/1912 turrets, the guns were separated by a 25 mm (1.0") splinter bulkhead. Following the Dogger Bank action, German mountings were modified to improve flash precautions. Double flap doors were installed at the beginning and end of the cartridge hoist and ready ammunition was removed from the gun houses.

• The gun axes were 106.3 in (270 cm) apart.