Tags: Weapon.
There have been a number of 18 inch torpedoes in service with the United Kingdom.These have been used on ships of the Royal Navy and aircraft of both the Fleet Air Arm and Royal Air Force while Royal Navy surface ships and submarines use 21 inch torpedoes. Note that the British 18 inch torpedoes were 17.72 inches (45.0 cm) in diameter beginning with the Fiume Whitehead torpedo of 1890.