QF 4.7 inch Mk V naval gun

QF 4.7 inch Gun Mk V
On troopship SS Orca, March 1919
Type	Naval gun Coast defence gun
Place of origin	United Kingdom  Empire of Japan
Service history
In service	1900–1945
Used by	British Empire
Wars	World War I World War II
Production history
Designer	Elswick Ordnance
Designed	ca. 1895
Variants	Mark V, Mark V*
Specifications
Weight	Barrel & breech 5,936 pounds (2,693 kg)
Barrel length	212.6 inches (5.40 m) (45 cal)
Shell	Separate loading QF 45 pounds (20.41 kg) Common Pointed, Lyddite
Calibre	4.724 inches (120 mm)
Breech	single motion interrupted screw
Recoil	8 inch
Elevation	-10° to +20°
Muzzle velocity	2,350 feet per second (720 m/s)
Maximum firing range	16,500 yards (15,100 m)

The QF 4.7 inch Gun Mark V originated as a 4.7 inches (120 mm) 45-calibre naval gun produced for export by the Elswick Ordnance Company in the 1890s and used by various countries.

The Royal Navy did not adopt the gun, but several were adopted by the army as coast defence guns around the United Kingdom from 1900 onwards. During World War I, the UK acquired 620 of a version manufactured in Japan, and mounted them as anti-submarine guns on merchant ships and troop ships, under the designation Mark V*. Many of these guns were used again in World War II on defensively armed merchant ships and troop ships.

On 10 March 1917 the crew of a single gun on the merchant ship SS Otaki fought a notable action against the heavily armed German commerce raider SMS Möwe. They managed to set the Möwe on fire and inflicted severe damage before the Otaki was sunk. Otaki's commander Archibald Bisset Smith went down with his ship and was eventually awarded a posthumous Victoria Cross for refusing to surrender his ship.