This instructional film made by the Royal Air Force describes the Mark XII aircraft launched torpedo, used by Fleet Air Arm and RAF Coastal Command. 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. The 18 inch MK XII torpedo was used by the Swordfish in sinking the German battleship Bismarck. The contact pistol (seen at the 2:51 mark) is fitted and when the point of one of the "whiskers" strikes the enemy hull, the detonator is fired and the TNT warhead explodes.
Date Of Design: 1935
Date In Service: 1937
Weight: 1,548 lbs. (702 kg)
Overall Length: 16 ft 3 in (4.953 m)
Negative Buoyancy: about 230 lbs. (104 kg)
Explosive Charge: 388 lbs. (176 kg) TNT
Range / Speed: 1,500 yards (1,370 m) / 40 knots
3,500 yards (3,200 m) / 37 knots
Power Burner-cycle, about 140 hp @ 40 knots
Note: The Mark XII was an improved Mark XI. It was the standard airborne torpedo for the first half of World War II and still in limited use until the end.
The modern torpedo is a self-propelled weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with its target or in proximity to it.
Historically, it was called an automotive, automobile, locomotive or fish torpedo; colloquially called a fish. The term torpedo was originally employed for a variety of devices, most of which would today be called mines. From about 1900, torpedo has been used strictly to designate an underwater self-propelled weapon. The original torpedo is a kind of fish: an electric ray.
While the battleship had evolved primarily around engagements between armoured ships with large-caliber guns, the torpedo allowed torpedo boats and other lighter surface ships, submersibles, even ordinary fishing boats or frogmen, and later, aircraft, to destroy large armoured ships without the need of large guns, though sometimes at the risk of being hit by longer-range shellfire.