57mm Bofors SAK-57


USA: Mk 110


Overview


57mm Mk 110

US Navy 57mm Mk 110 being fired on a Freedom class littoral combat ship in 2010.
Source: US Navy - © Public domain

Origin
Sweden
Type
Naval gun
Entered service
1966 (Mark 1)
1985 (Mark 2)
1998 (Mark 3)
Status
In service
Development
1964 - 1966 (Mark 1)
1977 - 1982 (Mark 2)
1991 - Late 1990's (Mark 3)
Developer
Sweden - Bofors AB
Production
1966 - Late 1970's (Mark 1)
1985 - 2000's? (Mark 2)
Late 1990's - Present (Mark 3)
Producer
Sweden - Bofors AB (now BAE Systems)
United States - BAE Systems
Number produced
About 80 Mark 1
25 Mark 2
Designations
SAK-57 / SjöAutomatKanon 57mm
Swedish for "naval automatic gun 57mm"
Mk 110 Mod 0 (US Navy)

Variants


57mm SAK-57 Mark 1

First iteration of the 57mm Bofors L/70 gun turret as introduced in 1966. Easily identified by the more squared housing with large local control window. Often fitted with rails for flares on either side of the turret. The Mark 1 has a total of 168 rounds in the turret, with more stowed below deck.

57mm SAK-57 Mark 2

Improved 57mm L/70 gun mount that introduced the lower RCS plastic housing. Rate of fire has been increased to 220 rpm, even though water cooling was omitted. Turret weight has been further reduced with smaller ammunition stowage in the turret, but adding intermediate magazines in the hoists to retain the volume of fire. A much improved stabilization system makes the Mark 2 more useful against inbound anti-ship missiles.

57mm SAK-57 Mark 3 (US Mk 110)

Updated Mark 2 turret for use with the programmable 3P ammunition. A muzzle velocity radar is mounted above the gun to adjust programming to the exact ballistic conditions when firing. Produced in the United States as the Mk 110.

57mm SAK-57 Mark 3 in stealth housing

Alternative turret cover design for the SAK-57 Mark 3. A more angular housing that stores the gun barrel in a downward position when the gun is not in use. This reduces the radar cross signature even further while not exposing the round barrel.

Details


Facts 57mm SAK-57 Mark 1 57mm SAK-57 Mark 2 57mm SAK-57 Mark 3
General
Origin
Sweden
Type
Naval gun
Ordnance
Type
57mm L/70 glycol-water-cooled gun
Cartridge
57x438mmR
Rate of fire
200 rpm
Range
13.8 km for high explosive
17 km for extended range
7.6 km anti-aircraft ceiling
Rifling
24 grooves, progressive right hand twist
Muzzle velocity
1.025 m/s HE
950 m/s HCER
Mount
Feed mechanism
Automatic loader
2 ammunition hoists (1 hoist model also produced)
Ammunition
4x 10 round magazine in turret
4x 32 round ready racks in turret
Additional ammunition stowage below deck
Traverse
360°, powered
Traverse rate
55°/s
Elevation
-10° to +78°, powered
Elevation rate
40°/s
Operation
Crew
1 local control or remote console operator
4 hoist operators
Fire control
External control using radar input or optronic director
Optional local control using gun sight
Stabiliser
Yes, electro-hydraulic
Flares
Optional cage-type flare launchers on either side of turret
Dimensions
Weight
6.3 t without ammunition
Length
6.3 m
Swept radius
4.3 m
Width
3.5 m (wider with flares)
Height
2.6 m
Deck penetration
Magazine and twin hoist system below deck

Media


Platforms


57mm Bofors SAK-57 Mark 1

Mandau class

Indonesian class of missile boat. Four vessels in class.

57mm Bofors SAK-57 Mark 2

Lekiu class

Malaysian class of frigate. Two ships in class. Single Mark 2 on bow with flares.

Related articles


57mm Bofors M1950

The Bofors SAK-57 is a further development of the earlier L/60 gun and ammunition as used in the very large twin barrel M1950 gun mount. The SAK-57 is much lighter with similar level of firepower for a shorter duration.