Mark 50 torpedo

The Mark 50 torpedo is a U.S. Navy advanced lightweight torpedo for use against fast, deep-diving submarines. The Mk 50 can be launched from all anti-submarine aircraft and from torpedo tubes aboard surface combatant ships. The Mk 50 was intended to replace the Mk 46 as the fleet's lightweight torpedo.^[1] Instead the Mark 46 will be replaced with the Mark 54 LHT.

Mark 50 Advanced Lightweight Torpedo
Mark 50 torpedo being fired
Type	Lightweight ASW torpedo
Place of origin	United States
Service history
Used by	United States Navy
Production history
Designer	Honeywell[1]
Designed	1974
Manufacturer	Alliant Techsystems
Produced	1991–
No. built	1000[2]
Specifications
Mass	approx. 800 lb (360 kg)[3]
Length	9.5 ft (2.9 m)[3]
Width	12.75 in (0.324 m)[3]
Warhead	HE shaped charge[1]
Warhead weight	100 lb (45 kg)[1][3]
Engine	Stored chemical energy propulsion system pump-jet
Propellant	sulfur hexafluoride, lithium
Operational range	16,000 yd (15 km) [4]
Maximum depth	> 1,900 ft (580 m)
Maximum speed	> 40 kn (74 km/h)[1][3]
Guidance system	Active or passive/active Acoustic homing[3]
Launch platform	Mark 32 surface vessel torpedo tubes, ASW aircraft (P-3 Orion), RUM-139 VL-ASROC

The torpedo's stored chemical energy propulsion system uses a small tank of sulfur hexafluoride gas, which is sprayed over a block of solid lithium, which generates enormous quantities of heat, which generates steam. The steam propels the torpedo in a closed Rankine cycle,^[5] supplying power to a pump-jet. This propulsion system offers the very important deep-water performance advantage in that the combustion products—sulfur and lithium fluoride—occupy less volume than the reactants, so the torpedo does not have to force these out against increasing water pressure as it approaches a deep-diving submarine.

General characteristics, Mk 50

• Primary function: air and ship-launched lightweight torpedo^[1][3]
• Contractor: Alliant Techsystems, Westinghouse^[3]
• Length: 9.5 ft (2.9 m)^[3]
• Weight: approx. 800 lb (360 kg)^[3]
• Diameter: 12.75 in (324 mm)^[3]
• Speed: > 40 kn (74 km/h)^[3]
• Power Plant: Stored Chemical Energy Propulsion System^[1]
• Propulsion: Pump Jet
• Guidance system: Active/passive acoustic homing^[1][3]
• Warhead: 100 lb (45 kg) high explosive ^[1][3]

Comparable weapons

• Stingray torpedo
• MU90 Impact

Notes

1. Thomas, Vincent C. The Almanac of Seapower 1987. Navy League of the United States (1987). ISBN 0-9610724-8-2. p. 190.
2. "Mark 50". Deagel, 2012. Accessed 5 Dec 2012.
3. "U.S. Navy Fact File: Mk-50 Torpedo" Archived 2016-10-12 at the Wayback Machine. The U.S. Navy—Fact File. Department of the Navy, 27 Nov 2012. Accessed 4 Dec 2012.
4. "Ticonderoga Class Aegis Guided Missile Cruisers, United States of America." Naval-technology.com. Net Resources International, 2012. Accessed 5 Dec 2012.
5. Hughes, T.G.; Smith, R.B. & Kiely, D.H. (1983). "Stored Chemical Energy Propulsion System for Underwater Applications". Journal of Energy. 7 (2): 128–33. Bibcode:1983JEner...7..128H. doi:10.2514/3.62644.

References

• MK-50 Advanced Lightweight Torpedo via FAS
• USA Torpedoes since World War II - navweaps.com
• Issues Related to the Navy's Mark-50 Torpedo Propulsion System, General Accounting Office, January 1989 - has diagrams showing internal general arrangement, retrieved December 18, 2012