5"/54 caliber Mark 45 gun

"5"/54 caliber gun" redirects here. For the earlier 5"/54 gun, see 5"/54 caliber Mark 42 gun.

"Mark 45" redirects here. For the torpedo, see Mark 45 torpedo.

Mark 45 5-inch/54-caliber lightweight gun
The latest version, a 5"/62 caliber Mark 45 Mod 4 firing
Type	Naval gun
Place of origin	United States
Service history
In service	• Mod 0: 1971[1] • Mod 1: 1980[1] • Mod 2: 1988[1] • Mod 4: 2000[2]
Used by	See users
Production history
Designed	1968[1]
Manufacturer	United Defense[1] (now BAE Systems Land & Armaments)
Produced	1971[1]
Specifications
Weight	• Mod 2: 21,691 kg (47,820.5 lb)[1] • Mod 4: 28,924 kg (63,766.5 lb)[1]
Length	• Mod 2: 8.992 m (29 ft 6.0 in)[3] • Mod 4: 10.008 m (32 ft 10.0 in)[2]
Barrel length	• Mod 2: 6.858 m (270.0 in)[3] Rifling: 5.82 m (229 in)[3] 8,000 rounds (barrel life)[3] • Mod 4: 7.874 m (310.0 in)[2] Rifling: 6.836 m (269.1 in)[2] 7,000 rounds (barrel life)[2]
Shell	Conventional: 31.75 kg (70.0 lb)[1]
Caliber	5.0 inches (127.0 mm)
Elevation	• -15°/+65°[3] Maximum elevation rate: 20°/sec[3]
Traverse	• 170° from either side of centerline[3] Maximum traversing rate: 30°/sec[3]
Rate of fire	16–20 rounds per minute automatic[4]
Muzzle velocity	• Mod 2: 2,500 ft/s (762.0 m/s)[1] • Mod 4: 2,650 ft/s (807.7 m/s)[1] • 1,500 ft/s (457.2 m/s) reduced charge for defilade fire or illumination rounds
Effective range	13 nmi (24.1 km)[4]
Feed system	600 rounds (Ticonderoga class) 680 rounds (Arleigh Burke class) 475–500 rounds (Other classes)

The 5-Inch/54-caliber (Mk 45) lightweight gun is a modern U.S. naval artillery gun mount consisting of a 5-inch (127 mm) L54 Mark 19 gun on the Mark 45 mount.^[1] Originally designed and built by United Defense, it is now manufactured by BAE Systems Land & Armaments after the former was acquired. The latest 5-inch/62-caliber version consist of a longer barrel L62 Mark 36 gun fitted on the same Mark 45 mount.^[1] The gun is designed for use against surface warships, anti-aircraft and shore bombardment to support amphibious operations.^[1]

The gun mount features an automatic loader with a capacity of 20 rounds. These can be fired under full automatic control, taking a little over a minute to exhaust those rounds at maximum fire rate. For sustained use, the gun mount would be occupied by a three-man crew (gun captain, panel operator, and ammunition loader) below deck to keep the gun continuously supplied with ammunition.

History

Development started in the 1960s as a replacement for the 5"/54 caliber Mark 42 gun system with a new, lighter, and easier to maintain gun mounting. In USN use, the Mark 45 is used with either the Mk 86 Gun Fire Control System or the Mk 160 Gun Computing System. Since before World War II, 5" has been the standard gun caliber for U.S. Naval ships. Its rate of fire is lower than the British 4.5-inch (114 mm) gun, but it fires a heavier 5" shell which carries a larger burst charge that increases its per-shell effectiveness against aircraft.

Variants

• Mod 0: used mechanical fuze setter. Two piece rifled construction, with replaceable liner
• Mod 1: electronic fuze setter replaces the mechanical one. Made with a unitary construction barrel, which has a life span approximately twice that of the Mark 42 gun.
• Mod 2: export version of Mod 1, but now used in the US Navy
• Mod 3: same gun with a new control system; never put into production
• Mod 4: longer 62 caliber barrel (Mod 1/2 54 caliber) for more complete propellant combustion, higher velocity, greater range at +20 nm (36 km)^[5] and thus more utility for land attack.

Special note

In sustained firing operations (Mode III), the gun is manned by a three-man crew all located below decks. These are a gun captain, a panel operator, and ammunition loader. In fully automatic non-sustained firing operations (Mode IV), the gun can be fired without any personnel inside the mount. However, sustained fire is limited to the capacity of the automatic loader (20 rounds). This means that there will be no-one at control panel for the gun to safe the weapon when having to fallback to verbal cease fire to the gun crew.

Users

Mark 45 gun aboard HMAS Arunta (FFH 151)

 Australia

Royal Australian Navy

• ANZAC-class frigates: Mod 2

In construction:

• Hobart class destroyer: Mod 4

 Denmark

Royal Danish Navy

• Absalon-class command and support ships

 Greece

Hellenic Navy

• Hydra-class frigates (MEKO 200 HN)

 Japan

Japan Maritime Self-Defense Force

• Atago-class guided missile destroyers: Mod 4
• 5000t-class destroyers: Mod 4

 Republic of Korea

Republic of Korea Navy

• King Sejong the Great-class guided missile destroyer: Mod 4
• Chungmugong Yi Sun-sin-class guided missile destroyer: Mod 4

 New Zealand

Royal New Zealand Navy: Mod 2

• ANZAC-class frigates

 Spain

Spanish Navy

• Álvaro de Bazán-class frigates: Mod 2

 Taiwan

Republic of China Navy

• Kee Lung-class guided missile destroyers

 Thailand

Royal Thai Navy

• Naresuan class frigates

 Turkey

Turkish Navy

• frigates (MEKO 200 TN II-B)
• Barbaros-class frigates (MEKO 200 TN II-A)
• Yavuz-class frigates (MEKO 200 TN)

5"/54 Mark 45 Mod 2 firing

Loading a round aboard USS Cole (DDG 67).

 United States

United States Navy

Active service ships:

• Tarawa-class amphibious assault ships (later removed)
• Ticonderoga-class guided missile cruisers: Mod 2^[4]
  • CG-52: Mod 4 after receiving the cruiser modernization
• Arleigh Burke-class destroyer guided missile destroyer:
  • DDG 51–80: Mod 2^[4]
  • DDG 81–112: Mod 4^[4]

Decommissioned:

• California-class cruisers
• Virginia-class cruisers
• Kidd-class destroyers
• Spruance-class destroyers

See also

• Extended Range Guided Munition: long range (~60 m) precision guided projectile program by Raytheon for the Mark 45 gun, canceled in 2008.
• Otobreda 127/54 Compact and Otobreda 127/64: contemporary 127mm naval gun from Italian manufacturer Oto Melara
• 4.5 inch Mark 8 naval gun: contemporary standard naval gun for British ships
• French 100 mm naval gun: contemporary standard naval gun for French ships
• Advanced Gun System: US Navy planned 155 mm gun for Zumwalt class destroyer

References

Notes

1. ^ ^{a b c d e f g h i j k l m n} Norman Polmar, pp. 492-493
2. ^ ^{a b c d e} "United States of America 5"/54 (12.7 cm) Mark 45 Mod 4". NavWeaps.Com. 18 April 2010. http://www.navweaps.com/Weapons/WNUS_5-62_mk45.htm. Retrieved 24 October 2010. 
3. ^ ^{a b c d e f g h} "United States of America 5"/54 (12.7 cm) Mark 45 Mods 0 - 2". NavWeaps.Com. 18 September 2007. http://www.navweaps.com/Weapons/WNUS_5-54_mk45.htm. Retrieved 24 October 2010. 
4. ^ ^{a b c d e} "The US Navy Fact File: 5-inch Mark 45 54-caliber lightweight gun". United States Navy. 20 February 2009. http://www.navy.mil/navydata/fact_display.asp?cid=2100&tid=575&ct=2. Retrieved 24 October 2010. 
5. ^ "5-inch 62-Caliber Mk 45 Mod 4 Naval Gun System". Brochure. BAE Sytems. http://events.us.baesystems.com/SAS/prodserv/pdf/BAE-Systems-Mk45-Mod4.pdf. Retrieved 5 October 2011. 

Bibliography

• Norman, Polmar (2005). The Naval Institute guide to the ships and aircraft of the U.S. fleet (18th ed.). Annapolis, MD: Naval Institute Press. pp. 492–493. ISBN 9781591146852. 

External links

• US Navy fact file
• BAE Systems: Mk 45 Mod 4 Naval Gun System
• BAE Systems: Mk 45 Naval Gun Overhaul and Upgrade
• NavWeaps.Com: 5"/54 (12.7 cm) Mark 45 Mods 0 - 2
• NavWeaps.Com: 5"/54 (12.7 cm) Mark 45 Mods 4
• FAS: Gunner officer information sheet

Video links

• BAE Systems promotional video of the Mk 45 Mod 4 gun on YouTube