The QF 4.5 inch (113 mm) gun has been the standard medium-calibre gun used by the Royal Navy as a medium range weapon capable of use against surface, aircraft and shore bombardment targets since 1938. This article covers the early 45-calibre family of guns up to the 1970s. For the current unrelated 55-calibre Royal Navy gun, see 4.5 inch Mark 8 naval gun, manufactured by BAE Systems.
Note that all British 4.5 inch naval guns actually have a calibre of 4.45 inches (113 mm)[1].
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History
From the BL Mark I of 1916, the QF 4.7 inch gun (120 mm) was the mid-calibre weapon of choice for the Royal Navy, used particularly on destroyers. Apart from some ships armed with QF 4 inch guns due to supply problems, it remained the standard weapon for destroyers up to the W class destroyers of 1943. However, its usefulness as an anti-aircraft weapon had been limited by the failure to develop a mounting with elevation over 55°, the lack of a predictive fire control system in destroyer classes built prior to the introduction of the 4.7" twin mount, (see HACS) and the setting of fuzes by hand on early, prewar, mountings. Later 4.7" mountings used mechanical fuze setters that were identical to those used on the 4.5" mountings.[2]
The QF 4.5 inch L/45 (113 mm) was developed originally as a dual-purpose weapon with which to arm aircraft carriers and reconstructed battleships and battlecruisers. It was later developed as a new dual-purpose weapon with which to arm destroyers, supplanting the ubiquitous 4.7 inch gun. Despite the lower calibre, it actually had a heavier shell, resulting in a more powerful weapon.
Variants
The nomenclature system for guns used by the Royal Navy can be somewhat confusing. The gun and mounting each have their own Mark number and a letter(s) giving additional information. QF stands for "quick firing", UD for "upper deck", BD for "between decks" and CP for "central pivot".
- QF Mark I: adopted after failure of a 5" gun project and used a fixed round, which proved to be somewhat heavy for the loaders to keep up the intended firing rate. Was fitted in twin mountings UD Mark III.
- QF Mark II: used by the British Army as an anti-aircraft gun, with the barrel lined down to 3.7 inches to use the same ammunition as existing weapons.
- QF Mark III: same as Mark I, except for firing mechanism. Was fitted in twin mountings BD Mark II, BD Mark II** and BD Mark IV. HMS Illustrious fired about 3000 rounds of 4.5" ammunition, at an average of 12 rounds per gun per minute, during one prolonged action in January 1941.[3]
- QF Mark IV: used a two part (charge and shell) ammunition system. Designed specifically for use by small warships. Fitted in mountings BD Mark IV, CP Mark V and UD Mark VI.
- QF Mark V: a further development of the Mark IV, designed from the outset for anti-aircraft use with remote power control (RPC, where the guns automatically train and elevate the target following the director) and a high rate-of-fire assisted by automatic ramming. Carried in the mounting UD Mark VI, with separate high-angle and low-angle hoists for the two types of ammunition (AA and SAP/HE) and a third for the cartridges. The rate of fire of the Mk V was 24 rounds per minute when power-loaded, 12-14 when hand-loaded, and up to 18 in burst mode when hand-loaded.
Some 800 naval 4.5" guns of various marks were built.
During the 1950s, a change was made in designating the weapons systems which focussed on the gun mount rather than the gun itself. Together with a change from Roman numerals, the Gun QF Mark V on mounting BD Mark VI became simply the Mark 6. The Mark 7 was never produced as the planned Malta class aircraft carriers they would have been used on were never built.
The majority of new escort vessels built for the Royal Navy in the 1950s and 1960s carried at least one Mark 6 mounting, with two in the Leopard class frigate and County class destroyer and three in the Daring class destroyer. This gave these ships a level of firepower unprecedented only 15 years earlier. The Type 81 Tribal class frigates were an exception, using reconditioned Mark V mounts from scrapped C class destroyers that were fitted with RPC and known as the Mark 5* Mod 1.
The evolution of the 45-calibre 4.5 inch gun family ended with the Mark V gun / Mark 6 mounting. It has been replaced by a new weapon of original design, the 4.5 inch Mark 8 with a 55 calibre-long barrel.
Use
Ships with 4.5 inch guns QF Mark I in twin mounting UD Mark III
- aircraft carrier Ark Royal
- Dido class cruisers Scylla and Charybdis
- naval auxiliaries
Ships with 4.5 inch guns QF Mark III in twin mounting BD Mark II
- reconstructed Queen Elizabeth class battleships Queen Elizabeth and Valiant
- reconstructed Renown class battlecruiser Renown
- Illustrious class aircraft carrier
- aircraft carrier Indomitable
- Implacable class aircraft carrier
Ships with 4.5 inch guns QF Mark III in twin mounting BD Mark II**
- Audacious class aircraft carrier, Eagle and Ark Royal
Ships with 4.5 inch guns QF Mark III in twin mounting BD Mark IV
- Battle class destroyer
- Nueva Esparta Class Destroyer D-11 Nueva Esparta, D-21 Zulia and D-31 Aragua
Ships with 4.5 inch guns QF Mark IV in single mounting CP Mark V
- Z class destroyer
- Ca, Ch, Co and Cr class destroyer
- "1944" Battle class destroyer
Ships with 4.5 inch guns Mark 5* (rebuilt mounting CP Mark V).
- rebuilt Ca class destroyer (Mark 5* Mod 1)
- Type 81 Tribal class frigate (Mark 5* Mod 2)
Ships with 4.5 inch guns QF Mark V in twin mounting UD Mark VI (later renamed gun Mark 6)
- Daring class destroyer
- County class destroyer
- Type 12 Whitby class frigate
- Type 12I Rothessay class frigate
- Type 12M Leander class frigate
- Type 41 Leopard class frigate
- Type 61 Salisbury class frigate
- Nueva Esparta Class Destroyer D-11 Nueva Esparta, D-21 Zulia and D-31 Aragua
See also
Media related to QF 4.5 inch Mk I - V naval gun at Wikimedia Commons- 4.5 inch Mark 8 naval gun The Royal Navy's current, but unrelated, 4.5" gun
- 5"/38 caliber gun and 5"/54 caliber Mark 42 gun, the US Navy equivalents
- Newsreel video of HMS Scylla fighting the Luftwaffe with her 4.5 inch guns while protecting convoy PQ18
References
- ^ Jane's Ammunition Handbook, 1999-2000 Edition. http://www.janes.com
- ^ Destroyer Weapons of WW2, Friedman, p96
- ^ Naval Weapons of WW2, Campbell, p17
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