Mark 13 torpedo

Mark 13 torpedo
A Mark 13B torpedo being loaded onto a TBF Avenger aboard the Wasp in 1944; the torpedo is fitted with wooden breakaway nose and tail protection which is shed upon hitting the water
Type	Aerial torpedo
Place of origin	United States
Service history
In service	1936–1950
Used by	United States Navy
Wars	World War II
Production history
Designer	Bureau of Ordnance Bureau of Aeronautics
Designed	1925
Manufacturer	Naval Torpedo Station Pontiac Motor Division Amertorp Corporation International Harvester
Produced	1942-1945
No. built	16,600
Variants	Mod 1 Mod 2 Mod 2A - Mod 13
Specifications
Mass	2216 pounds
Length	161 inches
Diameter	22.5 inches
Effective firing range	6300 yards
Warhead	Torpex
Warhead weight	600 pounds
Detonation mechanism	Mk 8, contact
Engine	Turbine
Maximum speed	33.5 knots
Guidance system	gyroscope
Launch platform	Douglas TBD Devastator Grumman TBF Avenger

The Mark 13 torpedo was the U.S. Navy's most common aerial torpedo of World War II. It was the first American torpedo to be originally designed for launching from aircraft only.

At the close of the war, the Mark 13 was considered one of the most reliable air-dropped torpedoes available, "universally accepted as the best aircraft torpedo owned by any nation." They were also used on PT boats.

Design

Mark 13 torpedo's general arrangement, as published in a service manual

Douglas TBD Devastator making a practice drop with a Mark 13 torpedo, October 20, 1941

Originating in a 1925 design study, the Mark 13 was subject to changing USN requirements through its early years with resulting on-and-off development. Early models—even when dropped low to the water at slow speeds—were prone to running on the surface, or not running at all. By late 1944, the design had been modified to allow reliable drops from as high as 2,400 ft (730 m), at speeds up to 410 knots (760 km/h). The final Mark 13 weighed 2,216 lb (1,005 kg); 600 lb (270 kg) of this was the high explosive Torpex.

The Mark 13 was designed with unusually squat dimensions for its type: diameter was 22.4 inches (570 mm) and length 13 feet 5 inches (4.09 m). In the water, the Mark 13 could reach a speed of 33.5 knots (62.0 km/h; 38.6 mph) for up to 6,300 yards (5,800 m). The Mark 13 ran 12.8 knots (23.7 km/h; 14.7 mph) slower than the Mark 14 torpedo. 17,000 were produced during the war.

The Mark 13 was very similar in design to the Mark 14 and Mark 15 torpedoes which suffered from problems such as submerged running approximately ten feet lower than set, contact exploder duds and magnetic trigger premature explosions. The Mark 13 design avoided these problems with its larger diameter, lesser mass, lesser negative buoyancy, slower running speed and the lack of a magnetic influence feature in its Mark IV exploder.

See also

• GT-1 (missile)

External links

• The short film Aerial Torpedo Attack - High Speed High Altitude is available for free download at the Internet Archive [more]

Notes

1. ^ National Museum of the United States Air Force. Mark 13 Torpedo". Archived on July 9, 2006.
2. ^ NavWeaps (18 February 2005). "USA Torpedoes of WWII". Retrieved 2 August 2005.
3. ^ Milford, Frederick J. U. S. Navy Torpedoes; Part One: The great torpedo scandal, 1941–43. The Submarine Review, April 1996. Archived on October 14, 2007.
4. ^ Milford, Frederick J. U. S. Navy Torpedoes; Part Two: The great torpedo scandal, 1941–43. The Submarine Review, October 1996. Archived on December 10, 2005.