| Mark 37 torpedo | |
|---|---|
 Mark 37 torpedo at the German Marine Museum Wilhelmshaven | |
| Type | Acoustic torpedo[1] |
| Place of origin | United States |
| Service history | |
| In service | 1956[1]-1972 |
| Used by | United States Navy Israeli Navy Royal Netherlands Navy |
| Production history | |
| Designer | 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] |
TheMark 37 torpedo is atorpedo with electrical propulsion, developed for theUS Navy afterWorld War II. It entered service with theUS Navy 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.[citation needed]
Its engineering development began in 1946 byWestinghouse. It was largely based on the concept of thepassive homingMark 27,[2] with addedactive homing system tested on modifiedMark 18s, and a new torpedo body. Between 1955 and 1956, thirty torpedoes were produced for development testing, with large-scale production commenced shortly afterwards.[3]
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 one-inch (25 mm)-thick guide studs were attached to the torpedo, which although 19 inches (480 mm) in diameter was designed to be used only from 21-inch (533 mm) torpedo tubes.[4]
The guidance of a Mk37 mod 0 torpedo was done by agyroscope 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 aDoppler-enabled active sonar homing, withmagnetostrictivetransducers operating at 60 kHz. The electronics was based on miniaturevacuum tubes, later on solid-state semiconductor devices.[citation needed]
The mod 1 torpedoes were longer, slower and heavier than mod 0, but offered bettertarget acquisition capabilities and higher ability to intercept agilesubmarines. They usedwire-guidance.[5]
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 withpiezoelectric 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.[citation needed]
The torpedoes used Mark 46silver oxide batteries. These had a known tendency to overheat, occasionally igniting or exploding. Training torpedoes used rechargeablesecondary batteries.[citation needed]
The efficiency of Mk 37 torpedoes was high for targets with speed lower than 20knots (37 km/h; 23 mph) and depth less than 1,000 ft (300 m). As submarines with higher speeds and operating depths appeared, new torpedoes were developed. Of them, the export models NT37C, D, E, and F are based on the Mk37 design.[citation needed]
For a long time, the Mark 37 was a primary U.S.submarine-launchedASW torpedo. It was replaced by theMark 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.[6]
The Mk 67 submarine launched mobilemine is based on a Mark 37 torpedo body.[7] It entered service in 1983 and is capable of swimming as far as 10 miles[clarification needed] through or into a channel, harbor, shallow water area and other zones which would normally be inaccessible to the vessel laying it. After reaching the target area it sinks to the sea bed and acts like a conventionally laidinfluence mine.[7] Theexploder in the Mk 67 warhead iscomputerised and incorporates magnetic, acoustic and pressure sensors.[8]
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