Germany 40.6 cm/52 (16") SK C/34 and 42 cm/48 (16.5") SK C/40 (original) (raw)

Turret intended for "H" Battleships.

These guns were intended for the "H" class battleships which were laid down in 1939 but never completed. This weapon was a good design, but it could be said that it had an excessively high muzzle velocity, hence giving it minimal deck penetration even at long ranges.

Accounts differ as to the actual number of guns completed, but there appears to have been twelve. There were three versions of this weapon; the original prototype for proof and experimental testing; three guns built to the naval pattern and intended for the "H" battleships; and eight finished to a modified design for coastal artillery use and also known as Adolph. The coast artillery version had a similar construction to the naval version but with a larger chamber. The naval guns were completed as one left hand and two right hand. Only one of these had power ramming.

These naval guns were placed on BSG (Bettungschiess-Gerüst - "Platform firing framework") mountings and sent to the Hel Peninsula in Poland to become Battery Schleswig-Holstein. All three guns were emplaced and test fired, but shortly afterwards they were dismantled and were sent to France where they were made part of Battery Lindemann, named after the Captain of the battleship Bismarck. This battery was located near Sangatte in France where they often fired across the Channel at Dover.

The eight coastal artillery guns were sent to Norway to be employed to protect Narvik and Tromsø, with one gun being lost in transit. Of the remaining seven guns, three were emplaced as Battery Dietl on the island of Engeløya and the other four were mounted as Battery Trondenes near Harstad. At the end of the war, the guns were taken over by the Norwegian Army along with 1,227 shells. A German gun crew trained the Norwegians in their use and the guns were actively used for about a decade. The three guns at Battery Dietl were decommissioned in the early 1950s and then scrapped in 1956. The battery at Trondenes was last fired in 1957 and formally taken out of commission in 1961. The guns then sat idle and were placed on sale for scrapping in 1968, but they still remain in place and one of them is currently open as a museum at Trondenes Fort.

As these guns had a rather thick barrel for their size, during the redesigns of the "H" class battleships in 1941 and 1942 (H-41 and H-42) it was proposed to bore them out and convert them into 42 cm/48 (16.54") weapons. One of the reasons behind this conversion was that this change would give these ships a larger caliber weapon than those planned for any known Allied battleship. None of the guns already built were ever converted and no new guns were started. The SK C/40 model year for this version is my estimate.

Constructed of a loose barrel, which was universally interchangeable between production guns, a loose liner which only fitted a particular gun, B tube, a jacket over the rear end of B tube, a breech end-piece thrust over the jacket and kept in place by a threaded ring, a breech block supporting piece inserted in the breech end-piece and secured by a threaded ring. A retaining ring with two fittings for transmitting rotation forces was screwed onto the rear of the barrel. Used a horizontal sliding breech block, similar to other large-caliber German naval guns.

The data that follows is specifically for the 40.6 cm (16") Naval version except where noted. Actual bore diameter of all versions was 40.64 cm (16.0").

• ^The sliding breech block weighed 7,940 lbs. (3,600 kg), the barrel 91,710 lbs. (41,600 kg) and the liner 45,860 lbs. (20,800 kg). The prototype gun differed in that the barrel weighed 83,110 lbs. (37,700 kg) and the liner 38,360 lbs. (17,400 kg).

• ^
  Actual designations for Projectiles

  APC L/4,4	40,6 cm Psgr. L/4,4 (m.Hb)
  HE L/4,6 base fuze	40,6 cm Spgr. L/4,6 Bdz
  HE L/4,8 nose fuze	40,6 cm Spgr. L/4,8 Kz (m.Hb)
  Adolph HE L/4,2	40,6 cm Ad.gr. L/4,2 Bdz u. Kz (m.Hb)
  HE L/4,1 base and nose fuze	40,6 cm Spgr. L/4,1 Bdz u. Kz (m.Hb)

• ^2.12.22.3German HE Nose Fuze and HE Base and Nose Fuze 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 the 12.7 cm SK C/34 datapage.
• ^A Note on Sources: Most references say that the Spgr. Kz (HE nose fuze) was 4,4 calibers long, but M.Dv. Nr. 198 lists it as 4,8 calibers long. This agrees with the length given in "German Capital Ships of World War Two."
• ^Burster weights (reiner Sprengstoff) from "German Capital Ships of World War Two." Burster composition from M.Dv. Nr. 198.
• ^The burster for the APC L/4,4 projectile was made from Fp 25, Fp 20, Fp 10, Fp 5 and Fp 5.
• ^The burster for the HE L/4,6 base fuze projectile was made from Fp 25, Fp 20, Fp 15, Fp 10, Fp 5 and Fp 5.
• ^The burster for the HE L/4,8 nose fuze projectile was made entirely with Fp 1.
• ^The burster for the Adolph nose fuze projectile was made entirely with Fp 1.
• ^The burster for the HE L/4,1 base and nose fuze projectile was likely 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.
• ^The case for the rear charge was changed to mild steel late in the war.
• ^The cartridge rim diameter was 465 mm.

Ranges of AP projectiles

All of the 2,271 lbs. (1,030 kg) projectiles had similar maximum ranges.

Ranges of Adolph HE projectiles

This data is from "Battleships: Axis and Neutral Battleships in World War II" for a muzzle velocity of 2,657 fps (810 mps) and is based upon the USN Empirical Armor Penetration Formula.

• ^The sources listed below differ as to the actual elevation span of the ship turrets. I have chosen to use those figures given in "German Capital Ships of World War Two."

One of the 40.6 cm Coastal Artillery Emplacements in Norway.

Side view of 40.6 cm SK C/34 turret under construction at the Krupp works.

Turret being lowered into its housing at the Krupp factory. The base includes over 200 ball bearings for the traversing mechanisms of the turret.

Breech-view of the twin turret mounting. Note the ammunition feed and rack mechanisms.

40,6 cm Spgr. L/4,4 Kz (m.Hb) now on display at the Norway Resistance Museum, Oslo, Norway. Photograph copyrighted by Graham Overman and used here by his kind permission.

Fore Charge (Vorkartusche) for 40,6 cm gun. Sketch from M.Dv. Nr. 190,4A6.

Rear Charge (Hülsenkartusche) for 40,6 cm gun. Sketch from M.Dv. Nr. 190,4A1.

Range Chart for a 1,323 lbs. (600 kg) projectile for a muzzle velocity of 3,084 fps (940 mps). Photograph courtesy of Peter Lienau.

Title of above Range Chart. Photograph courtesy of Peter Lienau.

Close up of the maximum range section. Large numbers are the range in hectometers, smaller numbers are time of flight in seconds. Photograph courtesy of Peter Lienau.

"Naval Weapons of World War Two" by John Campbell
"The Illustrated Encyclopedia of 20th Century Weapons and Warfare" by Bernard Fitzsimmons
"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
"German Artillery of World War Two" by Ian Hogg
"Naval Guns: 500 years of Ship and Coastal Artillery" by Hans Mehl
German Naval Guns: 1939 - 1945" by Miroslaw Skwiot
"German Capital Ships of World War Two" by M.J. Whitley
---
"Schlachschiff H" document by Dipl Ing Otto Riedel
"Munitionsvorschriften für die Kriegsmarine - Hülsenkartusche" M.Dv. Nr. 190,4A1 by Oberkommando der Kriegsmarine
"Munitionsvorschriften für die Kriegsmarine - Vorkartusche" M.Dv. Nr. 190,4A6 by Oberkommando der Kriegsmarine
"Übersicht über die für die Marinegeschütze und deren Abk K zu verwendende Munition und ihre Einzelteile einschließlich Salut- und Manöverladungen" M.Dv. Nr. 198 by Oberkommando der Kriegsmarine
---
Special help from Cliff McMullen, Peter Lienau, Charles Schedel and Thorsten Wahl

The Adolf Guns. Existing 40.6 cm guns in Norway.
Polish Coastal Defense Museum. Includes Battery Schleswig-Holstein fortifications where the German 40.6 cm guns were emplaced. Tourist Guidebooks in English are available from the Museum.

10 September 2007 - Benchmark
02 April 2011 - Additional details about coast artillery guns, added link to Adolph Guns
19 May 2012 - Updated to latest template
18 September 2016 - Converted to HTML 5 format
26 February 2019 - Reorganized notes and added data and sketches from M.Dv. Nr. 190,4A1 and M.Dv. Nr. 190,4A6
30 July 2019 - Added link to the Polish Coastal Defense Museum - Battery Schleswig-Holstein, added comments about use in Poland
14 February 2021 - Added photograph of 40,6 cm projectile on display in Norway
28 August 2024 - Added notes about burster and designation of Spgr. L/4,8 Kz (m.Hb), added propellant information