The Past And Future Of The 4.5-Inch Mark 8 Naval Gun

The 4.5-inch naval gun has served the test of time as the Royal Navy’s medium-calibre firepower of choice in 1938. But as we now see the first hull of the Type 26 Global Combat Ship take shape, it symbolises the move from the 4.5 inch gun, to the 5 inch gun, and therefore a long-awaited refresh in armament technology. So is the historically vigilant 4.5-inch gun still decisive in the battle-space at sea? And is its replacement worthy to fill the place?

Developed of the current Mark 8 type of 4.5 Inch naval gun started in the 1960s by the Royal Armament Research and Development Establishment, and built by Vickers Ltd Armament Division. It utilised a longer 55-calibre barrel, instead of the World War Two era 45-calibre barrel. This improved in accuracy and round velocity, but also the time at which the gun can be prepped and ready to fire, due to the single-barrel loading system, as well as ammunition advancements allowing rounds to be in ‘one-piece’. This allows the gun to compete as a defence mechanism with modern hostile missiles, enabling them to be intercepted quicker, and having a higher chance of doing so due to the increase in speed. Due to a smaller number of operators needed, the Mk 8 can be fitted on smaller ships with a limited crew capacity. All of this creates a very competitive 25 round per minute maximum fire rate.

An amazing picture of HMS Argyll firing her 4.5 Inch Gun on a Night GUNEX in the West Pacific

However, its entry into the RN was not said to be smooth. First fitted to the now training ship HMS Bristol in 1973, it proved to be less reliable than the older Mk V. During the Falklands War, there were reports of ships having to cease fire due to mechanical faults. This was later fixed in the two-tranche mod 1 modification of 1998, which replaced all hydraulic systems within the gun housing with electric, more reliable systems, as well as the housing itself, from the rounded and easily detectable by radar shape, to the flat angled surfaces design, with the intention of reducing radar cross-section; nicknamed the “Kryten gun”, after the robot from Red Dwarf, due to the character’s similarly shaped head. The mod 1 upgrade was implemented from 2005 to 2012 on 13 guns.

Type 23 Frigate HMS Iron Duke firing her 4.5 Inch Naval Gun

One of the many proposed plans falling victim to the SDSR10 was the "155mm Third Generation Maritime Fire Support" (155 TMF) program. This introduced the idea of interoperability between the British Army and the Royal Navy to develop a ‘common calibre’ of 155mm. This was supposed to improve logistics between the services, as well as keeping costs at a minimum, due to the ‘one size fits all’ outlook on the program.

But the Mark 8 is soon to be replaced with the 5-Inch Mark 45, which will first appear in the RN fleet on the Type 26 frigate. However, this gun has already seen time on board ships, most notably in the US Navy, on the Arleigh Burke-class destroyer. It has an inferior fire rate; at only 16-20 rounds per minute, and range approx 3 km short of the Mk 8, however, has a larger ‘burst charge’, complimented with 10° more elevation than the 4.5-inch Mk8, resulting in a more effective defence against aircraft. It is expected the T26 will be fitted with the mod 4 variant, which further reduces radar signature due to its flat-top turret, and with a longer 62-calibre barrel it has increased velocity and functionality for land attack. Amongst this, it is better integrated with modern systems, like the T26’s Type 997 Artisan 3D search radar and newly introduced Sea Ceptor, as well as having a superior traverse speed. The US Navy has investigated into guided ammunition systems for the gun, but at the moment, without success.

The BAE 5 Inch Mk45 Naval Gun, which will be equipped on the future Type 26 Frigates

But the iconic Mark 8 has many years left in service, being a key component of the Type 23 Frigates that will continue serving the Royal Navy until the mid 2030s, and part of the Type 45 Destroyers that will serve for decades longer than the T23s.

A 4.5 Inch Mk8 Naval Gun on a Type 45 Destroyer, on which it will serve for decades to come

So it seems that the future of naval guns in the Royal Navy is somewhat bright, due to proven and tested technology soon to be introduced to the RN. However, with BAE making advancements in electromagnetic railgun technology, the new Mark 45 may not be in service for as long as its iconic predecessor.