Mark 45 naval gun

Mark 45 naval gun. The Mark 45 is a 5-inch (127 mm) caliber, lightweight, single-barrel naval gun system designed and manufactured in the United States. It was developed in the late 1960s to replace the heavier, twin-barrel Mark 42 naval gun on United States Navy destroyers and cruisers. The system provides reliable, rapid-fire support for naval surface fire support, anti-surface warfare, and limited anti-air warfare roles.

Development and history

The development of the Mark 45 was initiated by the United States Navy in the 1960s to address the weight and manning issues associated with the preceding Mark 42 naval gun. The contract for design and production was awarded to Northern Ordnance, which later became part of FMC Corporation and subsequently United Defense. The primary goal was to create a lighter, more automated system with reduced crew requirements for installation on new classes of guided-missile destroyers like the Spruance-class destroyer. The first operational system, the Mod 0, entered service aboard the USS King (DDG-41) in 1971. Throughout the Cold War, the gun proved its utility during numerous exercises and deployments with the United States Seventh Fleet and other formations.

Design and specifications

The Mark 45 is a fully automated, remotely operated system from within the ship's Combat Information Center. Its key design features include a single 5-inch/54 caliber barrel, a vertically sliding wedge breech, and a below-decks automatic loader and magazine. The system uses separate-loading ammunition, where the projectile and the combustible cased charge are loaded independently. Standard ammunition includes high-explosive rounds, illumination rounds, and training rounds. Later variants, developed in conjunction with programs like the Advanced Gun System study, introduced longer 62-caliber barrels and enhanced control systems. The gun mount is constructed from lightweight materials, significantly reducing top-side weight compared to its predecessors, a critical factor for ship stability.

Operational history

The Mark 45 has seen extensive operational use with the United States Navy across multiple global conflicts. It was used for naval gunfire support during the Vietnam War by earlier destroyer classes. Its most notable combat employment came during the Gulf War, where it provided fire support for coalition forces. The system was also used in the Iraq War and during ongoing operations in the Persian Gulf. Beyond the U.S., allied operators have deployed the gun in various regional exercises and security operations. The system's reliability and accuracy have made it a staple for naval surface fire support missions for over five decades, serving on platforms from the Kidd-class destroyer to the modern Arleigh Burke-class destroyer.

Variants

*Mod 0: The original model introduced in 1971, featuring a 54-caliber barrel. *Mod 1: An upgraded version with improved reliability and a new digital control system. *Mod 2: A further refinement, often associated with the Vertical Gun for Advanced Ships technology demonstration. *Mod 4: The most advanced variant, featuring a longer 62-caliber barrel, increased range, and compatibility with specialized munitions like the Extended Range Guided Munition (ERGM) and the Bofors 3P round. This variant is standard on newer Flight IIA destroyers.

Operators

*: Installed on ''Hobart''-class destroyers. *: Used on Hydra-class frigates. *: License-built as the Mark 45 Mod 4 by Japan Steel Works for the Maya-class destroyer and Atago-class destroyer. *: On the Anzac-class frigates. *: On the KDX-III-class destroyers (Sejong the Great-class destroyer). *: On the Kee Lung-class destroyer (ex-Kidd-class destroyer). *: On the HTMS Bhumibol Adulyadej frigate. *: On the Barbaros-class frigate. *: Primary operator, on Ticonderoga-class cruisers and Arleigh Burke-class destroyers.

Category:Naval guns of the United States Category:5-inch artillery