 The availability, simplicity and light weight of the gun kept it in use in small vessels and many were later brought back into service on merchant vessels used for auxiliary duties in World War II or as saluting guns and sub-calibre guns for gunnery practice until the 1950s.Early in WWII, it was also pressed into service in ports around the British Empire, to defend against possible incursions by motor torpedo boats, until the modern QF 6 pounder 10 cwt gun became available.Royal Navy ships armed with QF 3-pounder Hotchkiss guns include