Mark 37 torpedo

Mark 37 torpedo
Westinghouse Electric[1] Underwater Sound Laboratory, Harvard University Ordnance Research Laboratory, Pennsylvania State University
Designed	1946[1]
Manufacturer	Naval Ordnance Station Forest Park[1]
Variants	Mark 37 Mod 1[1] Mark 37 Mod 2 Mark 37 Mod 3 NT37C NT37D NT37E NT37F
Specifications
Mass	1,430 pounds (650 kg)[1]
Length	135 inches (3.4 m)[1]
Diameter	19 inches (480 mm)[1] (21-inch guide rails)
Effective firing range	23,000 yards (21 km) at 17 knots, 10,000 yards (9.1 km) at 26 knots
Warhead	Mk 37 Mod 0, HBX-3[1]
Warhead weight	330 pounds[1]
Detonation mechanism	Mk 19 contact exploder
Engine	Electric[1]
Maximum speed	17 knots (31 km/h), 26 knots (48 km/h)
Guidance system	Gyroscope (initial), passive sonar (cruise) and Doppler active sonar homing (terminal) [1]
Launch platform	Submarines[1]

The Mark 37 torpedo is a

in the early 1950s, with over 3,300 produced. It was phased out of service with the US Navy during the 1970s, and the stockpiles were sold to foreign navies.

Development

Its engineering development began in 1946 by

Due to its electric propulsion, the torpedo swam smoothly out of the launch tube, instead of having to be ejected by pressurized air, therefore significantly reducing its acoustic launch signature. To allow for water flow around the torpedo while swimming out, several 1" thick guide studs were attached to the torpedo, which although 19" in diameter was designed to be used only from 21" torpedo tubes.[4]

The guidance of a Mk37 mod 0 torpedo was done by a gyroscope control during the initial part of its trajectory, where the gyro control achieved a straight run, a passive sonar homing system, and at the last 700 yards (640 m) by a Doppler-enabled active sonar homing, with magnetostrictive transducers operating at 60 kHz. The electronics was based on miniature vacuum tubes, later on solid-state semiconductor devices.

Modifications

The mod 1 torpedoes were longer, slower and heavier than mod 0, but offered better target acquisition capabilities and higher ability to intercept agile submarines. They used wire-guidance.

The efficiency of Mk37 torpedoes was high for targets with speed lower than 20 knots (37 km/h) and depth less than 1,000 ft (300 m). As submarines with higher speeds and operating depths appeared, new torpedoes were developed. Of them, NT37C, D, E, and F are based on the Mk37 design.

In 1967, the mod 0s started being refurbished as mod 3, and mod 1 as mod 2. These modifications involved many changes including replacement of magnetostrictive transducers with

ones, and resulted in target acquisition range increased from 700 yd (640 m) to 1,000 yd (910 m) without loss of sensitivity with increasing depth.

The torpedoes used Mark 46

.

For a long time, the Mark 37 was a primary U.S. submarine-launched ASW torpedo. It was replaced by the Mark 48 starting in 1972. The remaining inventory was then rebuilt and sold to several countries, including Israel, as the NT-37C after the vacuum tube guidance systems were replaced by solid-state electronics and the electric propulsion was replaced with a liquid monopropellant.^[5]

Other uses

The Mk 67 submarine launched mobile

General characteristics

• Power plant: Mark 46
  silver-zinc battery
  , two-speed electric motor
• Length: 135 inches (340 cm) (mod.0), 161 inches (410 cm) (mod.1)[5]
• Weight: 1,430 pounds (650 kg) (mod.0), 1,660 pounds (750 kg) (mod.1)^[5]
• Diameter: 19 inches (48 cm)^[5]
• Range: 23,000 yards (21 km) at 17 knots, 10,000 yards (9.1 km) at 26 knots
• Depth: 1,000 feet (300 m)
• Speed: 17 knots (31 km/h), 26 knots (48 km/h)
• Guidance system: active/passive sonar homing; passive until about 700 yards (640 m) from target, then active; mod.1 with wire-guidance^[5]
• Warhead: 330 pounds (150 kg)
  exploder
• Date deployed: 1957^[5]

References

External links

• Mk3-7 torpedo load, USS Torsk SS-423
• SOVIET SEIZURE OF US PRACTICE TORPEDO
• Tom Pelick: A historical perspective: U.S. Navy's First Active Acoustic Homing Torpedoes