There have been a number of 18-inch

torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, ...

es in service with the United Kingdom. These have been used on ships of the

Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against Fr ...

and aircraft of both the

Fleet Air Arm The Fleet Air Arm (FAA) is one of the five fighting arms of the Royal Navy and is responsible for the delivery of naval air power both from land and at sea. The Fleet Air Arm operates the F-35 Lightning II for maritime strike, the AW159 Wi ...

and

Royal Air Force The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) an ...

, while Royal Navy surface ships and submarines use 21-inch torpedoes. The British "18-inch" torpedoes were in diameter, beginning with the "Fiume"

Whitehead torpedo The Whitehead torpedo was the first self-propelled or "locomotive" torpedo ever developed. It was perfected in 1866 by Robert Whitehead from a rough design conceived by Giovanni Luppis of the Austro-Hungarian Navy in Fiume. It was driven by a t ...

of 1890.

45 cm "Fiume" (Whitehead) torpedo

First introduced into British service in 1894. * Year : about 1888 * Weight : * Length : * Warhead : wet gun-cotton * Performance : for * Propulsion :

Compressed air Compressed air is air kept under a pressure that is greater than atmospheric pressure. Compressed air is an important medium for transfer of energy in industrial processes, and is used for power tools such as air hammers, drills, wrenches, an ...

Mark V

Used on the River-class and 1905 Tribal-class destroyers. * Year : about 1899 * Weight : * Warhead : including pistol * Propulsion : Compressed air

Mark VI

Used on destroyers of the early 1900s. * Year : about 1904 * Performance : for or for * Propulsion : Compressed air

Mark VII and VII*

Introduced on the 1908 members of the 1905 Tribal class destroyers. Used by torpedo boats built before the First World War and destroyers. Used by RAF flying boats in the 1920s. * Year : 1907 * Warhead : TNT * Performance : ** Mark VII :
for
for ** Mark VII* :
for
for * Propulsion : Wet-heater

Mark VIII

* Year: 1913 * Role: Submarines and aircraft (Note: During World War II and after the Mk.VIII was a 21-inch torpedo) * Warhead: TNT * Propulsion: Wet heater * Performance: for

Mark XI

* Year: 1934 * Aircraft carried * Dimensions: dia. * Warhead: TNT * Propulsion: Burner cycle * Performance: for

Mark XII

Aircraft launched, used by

and

RAF Coastal Command RAF Coastal Command was a formation within the Royal Air Force (RAF). It was founded in 1936, when the RAF was restructured into Fighter, Bomber and Coastal Commands and played an important role during the Second World War. Maritime Aviation ...

Mark XIV

The Mark XIV was an aircraft-launched torpedo. Stocks were lost with the

fall of Singapore The Fall of Singapore, also known as the Battle of Singapore,; ta, சிங்கப்பூரின் வீழ்ச்சி; ja, シンガポールの戦い took place in the South–East Asian theatre of the Pacific War. The Empire ...

Mark XV

* Year: 1942 * Operators: Fleet Air Arm, RAF Coastal Command, Royal Navy * Role: Aircraft and Motor Torpedo Boats, 1943 onwards * Dimensions: × * Warhead: Torpex * Propulsion: Burner cycle * Performance: for or for

Mark XVI

Electric torpedo project not completed.

Mark XVII

* United Kingdom, 1944 * Aircraft launched * Operated by FAA, RAF Coastal Command, Blackburn Firebrand * Dimensions: × * Warhead: Torpex * Propulsion: Burner cycle * Performance: for

Mark 30

An air-dropped passive acoustic homing torpedo known as "Dealer" and "Dealer B". * Length: * Weight: * Performance: for or for