The QF 4.7 inch Gun Mark V originated as a 4.7 in 45-calibre naval gun designed by the Elswick Ordnance Company for export customers and known as the Pattern Y.

United Kingdom service

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. In 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.

Notable actions

On 10 March 1917 the crew of a single gun on the refrigerated cargo liner SS Otaki (1908) fought a notable action against the heavily-armed German commerce raider SMS Möwe (1914). They managed to set the Möwe on fire and inflicted significant damage before the Otaki was sunk. Otaki's Master Archibald Bisset Smith went down with his ship and was posthumously awarded the Victoria Cross for refusing to surrender his ship.