One of the largest guns ever constructed, this was probably an experimental weapon. Ordered in 1938, the prototype gun and cradle were apparently fired a few times although the proof mounting was not completed. It seems unlikely that this weapon was ever seriously intended to be used as an actual naval gun as even the gigantic H-44 battleship was to be armed "only" with 50.8 cm (20") guns.
Construction was of built up design consisting of four layers; a shrunk loose liner, A tube and two outer tube layers. Used a horizontal sliding breech block, similar to other Krupp designs.
Actual bore diameter was 53.34 cm (21.0").
The APC projectile is modeled in Nathan Okun's Facehard programs.
| Designation | 53 cm/52 (21") Gerät 36 |
|---|---|
| Ship Class Used On | Experimental |
| Date Of Design | 1938 |
| Date In Service | 1941 (?) |
| Gun Weight | Including breech mechanism: 329.8 tons (335.1 mt) |
| Gun Length oa | 1,090.55 in. (27.700 m) |
| Bore Length | 1,025.2 in. (26.040 m) |
| Rifling Length | 843.2 in. (21.417 m) |
| Number Of Grooves | (110) 0.236 in deep x 0.323 in (6.0 mm x 8.2 mm) |
| Lands | 0.277 in (7.03 mm) |
| Twist | Increasing RH 1 in 35.9 to 1 in 29.9 |
| Chamber Volume | 76,280 in3 (1,250 dm3) |
| Rate Of Fire | Probably less than 1 round per minute |
| Type | Cartridge - Bag - Bag |
|---|---|
| Projectile Types and Weights 1 2 | APC L/4,9: 4,850 lbs. (2,200 kg)
HE L/4,9 nose fuze: 4,850 lbs. (2,200 kg) Coastal Light HE: 3,886 lbs. (1,400 kg) |
| Bursting Charge 3 | APC L/4,9: 100.2 lbs. (45.45 kg)
HE L/4,69 nose fuze: 485 lbs. (220 kg) Coastal Light HE: N/A |
| Projectile Length | APC L/4,9: 103.2 in (262.1 cm)
HE L/4,9 nose fuze: 103.8 in (264.6 cm) Coastal Light HE: N/A |
| Propellant Charge 4 | Fore: 551 lbs. (250 kg) Gu RP 5 Middle: 551 lbs. (250 kg) Gu RP Main: 661 lbs. (300 kg) Gu RP Brass case for main charge: 346 lbs. (157 kg) |
| Muzzle Velocity | APC and HE: 2,690 fps (820 mps)
Coastal Light HE: 3,410 fps (1,040 mps) |
| Working Pressure | 19.0 tons/in2 (3,000 kg/cm2) |
| Approximate Barrel Life | N/A |
| Ammunition stowage per gun | N/A |
- ^A Note on Sources: Projectile and burster weights from the post-war National Archives document "DEFE 15/247." This may have been one of the sources used by Campbell in "Naval Weapons of World War Two" which lists these same values. These values are also listed in the APC projectile sketch shown above which is dated April-May 1943. An earlier German document dated 1942 from the Bundesarchiv folder RH 8/3798K notes a projectile weight of 2,335 kg (5,148 lbs.). This earlier document may have been for the original projectile design which was later replaced by the lighter projectiles.
- ^
Actual German designations APC L/4,9 53.3 cm Psgr. L/4,9 (m.Hb) HE L/4,9 nose fuze 53.3 cm Spgr. L/4,9 Kz (m.Hb) Coastal Light HE N/A - ^Burster weights shown here are the Gesamtgewicht (gross weight) values and not the reiner Sprengstoff (actual explosive weight) values shown on most NavWeaps datapages.
- ^These guns used a three part charge with the fore and middle charges being identical. The rear or main charge was in a brass cartridge case, similar to those used for other German naval guns.
- ^Gu RP was a nitroguanidine propellant in hollow tubular form.
| Elevation | Range for APC & HE | Range for Light HE |
|---|---|---|
| 50 degrees | about 51,950 yards (47,500 m) | about 71,080 yards (65,000 m) |
"Naval Weapons of World War Two" by John Campbell
"DEFE 15/247" National Archives
---
Special help by Zhu Shipeng, Maciej Chodnicki, Bene Adler and Thorsten Wahl
21 March 2007 - Benchmark
19 May 2012 - Updated to latest template
26 December 2023 - Converted to HTML 5 format and added sketch of APC
16 August 2024 - Minor changes
24 April 2025 - Added Coastal Light HE and notes about projectile and burster weights