Wikipedia

Bofors 57 mm Naval Automatic Gun L/60

(Redirected from 57 mm lvakan M/50)
Not to be confused with Bofors 57 mm Naval Automatic Gun L/70.

Bofors 57 mm Naval Automatic Gun L/60 (Swedish: 57 mm sjöautomatkanon L/60 (57 mm SAK 60)),[1][2] also known as 57 mm/60 (2.25") SAK Model 1950[3] and the like (full English product name: Bofors 57 mm Automatic A.A. Gun L/60 In Stabilized Twin Turret),[4] was a twin-barreled 57 mm (2.2 in) caliber fully automatic dual purpose naval artillery piece designed by the Swedish arms manufacturer Bofors from the early 1940s to the early 1950s to meet a request from the Dutch Navy.[1] Besides the Dutch Navy, the weapon was also adopted by the Swedish and the French Navy, most predominantly by the latter.[3]

Bofors 57 mm Naval Automatic Gun L/60
Swedish Bofors 57 mm SAK 60 (57 mm akan m/50) on the destroyer HSwMS Småland
TypeNaval Gun
Place of originSweden
Service history
In service1952–1990
Used byDutch Navy
Swedish Navy
French Navy
Production history
Designed1950
ManufacturerBofors
Produced1950
Specifications
MassTraversing mass: 24 t (24 long tons; 26 short tons)
Barrel length60 calibres 3.420 m (11.22 ft)
Crew8
Shell57 × 438 mm R (m/50)
Shell weight2.6 kg (5.7 lb)
Calibre57 mm (2.2 in)
Elevation-9°/+90°, 30°/s
Traverse-360°, 30°/s
Rate of fire2 × 130 rounds/min
Muzzle velocity850–920 m/s (2,800–3,000 ft/s)
Effective firing range13,000 m (43,000 ft) (max)
5,000 m (16,000 ft) (practical)
5,500 m (18,000 ft) AA ceiling

Design

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The Bofors 57 mm Naval Automatic Gun L/60 is at its core a scaled up version of the famous Bofors 40 mm Automatic Gun L/70, but constructed as a twin-gun system sharing the same receiver/mantle with ammunition feeding from the sides into each gun.[1] The guns were water-cooled and fed by large 80-cartridge magazines that allowed several long bursts to be fired without reloading.[3]

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    French "57mm/60 modèle 1951" on display at Port-Louis naval museum.
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    French "57mm/60 modèle 1951" on display at Port-Louis naval museum.

Use in the Dutch Navy

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Dutch Bofors 57 mm SAK 60 on the cruiser HNLMS De Ruyter.

The Dutch were the initial users of the Bofors 57 mm Naval Automatic Gun L/60. As part of rebuilding the Dutch Navy post World War II, the Dutch Navy had requested several naval gun systems to be developed by Bofors for their next generation of naval-vessels,[5] one being a twin-barreled 57 mm dual-purpose gun for the planned De Zeven Provinciën-class cruisers HNLMS De Ruyter and De Zeven Provinciën.[1] This request led to the creation of the Bofors 57 mm Naval Automatic Gun L/60, which entered active service with the Dutch Navy in 1953 mounted on the cruisers De Ruyter and De Zeven Provinciën.

Use in the Swedish Navy

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Swedish 57 mm akan m/50 on the destroyer HSwMS Småland

Following the Dutch example, the Swedish navy decided to acquire the new 57 mm system for a new generation of destroyers in 1950. In Swedish service the weapon was fitted to the Halland-class destroyers HSwMS Halland and Småland, both of which entered service in 1956.[1] The weapon was initially designated 57 mm automatkanon m/50 (57 mm akan m/50),[6] meaning "57 mm autocannon m/50", but around 1970 the weapon was redesignated to 57 mm torndubbelautomatpjäs m/50 (57 mm tdblapjäs m/50),[7][8] meaning "57 mm turret double automatic piece m/50" (literal).

The gun was in use until the Halland-class destroyers were taken out of service.

Use in the French Navy

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Two French Le Normand-class frigates fitted with 57mm/60 mle 51 turrets on the bow.

The Bofors 57 mm L/60 naval gun was also purchased by the French Navy and came to serve on a number of naval-vessels under the designation 57mm/60 modèle 1951 (57mm/60 mle 51) from 1952 onward, although primarily post 1956.[3] The French navy version of the system featured a French designed naval mount that maintained the system in mechanical equilibrium, even when firing.[3] The French mounting was some 8 tons lighter than the Dutch/Swedish version.[citation needed]

In French service the gun notably armed light escorts as main guns and larger ships as secondary guns. The following French ships were armed with the 57mm/60 mle 51 system:[3]

See also

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References

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Notes

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  1. ^ a b c d e "Bofors automatic 57mm Dual-Purpose guns". tfd.chalmers.se. Archived from the original on 2007-07-01. Retrieved 2021-09-14.
  2. ^ "030306_SAK57_Mk3.pdf" (PDF). boflv.se. Bofors Luftvärnsförening (Bofors Anti-Aircraft Association). 2003. Archived (PDF) from the original on 2010-09-11. Retrieved 2021-11-19.
  3. ^ a b c d e f "57 mm/60 Modèle 1951 on NavWeaps.com". navweaps.com. Archived from the original on 2016-08-19. Retrieved 2021-11-19.
  4. ^ Bofors (in Swedish). Karlskoga, Sweden: AB Bofors, Karlskoga (Boforskoncernen). 1958. p. 87.
  5. ^ "120 mm Bofors naval guns". tfd.chalmers.se. Archived from the original on 2007-05-18. Retrieved 2021-11-19.
  6. ^ Amreg Fl, Ammunitionsregister för flottan, 1955 (in Swedish). Stockholm, Sweden: Ammunitionssektionen, Marinförvaltningens Artilleribyrå. 1955.
  7. ^ Amreg Marinen, Ammunitionsregister för marinen, 1962, ändringar 1965 (in Swedish). Stockholm, Sweden: Kungliga Marinförvaltningen. 1965.
  8. ^ AMKAT, Ammunitionskatalog, Data och bilder, Marinen, 1977 års utgåva (in Swedish). Stockholm, Sweden: Swedish Defence Materiel Administration (FMV). 1977.
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