127mm Mk 42
Overview
127mm Mk 42
Side view of 127mm Mk 42 naval gun turret.
Source: www.mod.go.jp -
© copyright lies with original owner
Japan - (license production)
Japan
Australia
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Germany
Description
Introduction
The Mk 42 is an early Cold War era dual purpose naval gun turret of US origin. It was developed after World War 2 as a more capable turret to for all new major surface combattants to be introduced. The Mk 42 introduced a new heavier range of 127mm ammunition compared to World War 2. Today these dimensions are still the NATO specification for 127mm naval shells.
Design
The Mk 42 is a single gun turret with the 127mm 54-caliber Mk 18. For its time the Mk 42 was highly automated. The rate of fire is similar to earlier twin barrel designs. The turret is large and bulky since it houses some of the crew members. The two domes house the local fire control systems for surface fire (left) and anti-aircraft fire (right).
Fire control
On most ships the Mk 42 turret received fire direction from the Mk 68 gun fire-control system with its associated AN/SPG-53 radar system. For use against surface there is local fire control. This option was retained in all variants. Local fire control against aircraft was present, but removed in the 1960's during refit due to its limited use against jet aircraft. The Mk 42 Mod 8 was fitted with an on mount fire control radar, which proved to be unsuccessful.
Firepower
The Mk 42 fires 127mm shells with a weight of about 31 kg. Various types of ammunition are available. These incluse SAP, anti-aircraft, illumination and rocket assisted projectiles. The maximum range is 23.7 km against surface targets and the anti-aircraft ceiling is over 15 km. Upon introduction the rate of fire was 40 rpm. Issues with reliability were resolved by bringing rate of fire down to 28 rpm.
Platforms
Compared to World War 2 era designs the Mk 42 had a high rate of fire, more capable ammunition and higher level of automation. It was widely used on US ships and on those acquired or home built by US allies. Both the US and Japan fitted various classes of ship with the Mk 42. In US service the Mk 45 was introduced in the 1970's to replace the Mk 42 on new ships.
Variants
Details
Media
Mk 42 naval gun turret
Two Mk 42 naval guns of the Japanese Haruna Class Destroyer firing during an exercise.
Source: JMSDF
Copyright: Copyright lies with original owner
AN/SPG-53 radar on Mk. 68 GFCS
Mk. 68 gun fire-direction system with AN/SPG-53 radar.
Source: US Navy
Copyright: Public domain
127mm Mk 42
Forward view of 127mm Mk 42 naval gun turret.
Source: Hunini
Copyright: GNU Attribution - Share Alike license
Mk 42 naval gun turret
Forward view of the Mk 42 naval gun turret with 127mm Mk 18 gun.
Source: www.navweaps.com
Copyright: Copyright lies with original owner
Related articles
127mm Mk 45
The Mk 45 is the successor of the Mk 42 in US service. The Mk 45 is much smaller design. Both naval guns use the same range of 127mm ammunition.
127mm Compatto
The Italian Compatto is a 127mm naval gun that uses the same range of 127mm ammunition. In Japanese service both the Compatto and Mk 45 are successors to the Mk 42.