QF 4.7 inch Mk V naval gun

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

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.

During World War I, the UK acquired 620 of a version of the guns 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 again used in World War II to arm merchant ships and troop ships.

Notable actions
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 Möewe. They managed to set the Möewe 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.