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A modern torpedo is a self-propelled guided projectile that operates underwater and is designed to detonate on contact or in proximity to a target. Torpedoes are weapons that may be launched from submarines, surface ships, helicopters and fixed-wing aircraft, and from unmanned naval mines.

They are also used as parts of other weapons; the Mark 46 torpedo used by the United States becomes the warhead section of the ASROC (Anti-Submarine ROCket) and the Captor mine uses a submerged sensor platform that releases a torpedo when a hostile contact is detected.

Etymology

In naval usage, the term "torpedo" was first used in the American Civil War to refer to tethered naval mines, developed by Matthew F. Maury, a Confederate Admiral (these are what David Farragut was referring to when he ordered his men to "damn the torpedos, full speed ahead"). The word torpedo comes from the electric ray, one of the fishes of the family Torpedinidae.

This use of the word to refer to what are now called mines lasted until World War I, as other torpedoes were developed the term was modified to stationary torpedo and the term mine was also used.

History

Attempts had been made to develop unpowered, but directable towed torpedoes, such as Harvey's Sea Torpedo. But it was Ivan Lupis-Vukić, a retired Croatian naval engineer who served in the Austro-Hungarian navy, who constructed the first self-propelled torpedo prototypes and presented them to the emperor Franz Joseph in the port city of Rijeka in 1860. Robert Whitehead, an English engineer/entrepreneur, was working in the Trieste port on navy projects, so in 1864 Lupis made a contract with him in order to perfect the invention. This resulted in Minenschiff, the first self-propelling torpedo, officially presented to the imperial naval commission on December 21, 1866.

After the government decided to invest in the invention, Whitehead started the first torpedo factory in Rijeka. In 1870, they improved the devices to travel up to 1,000 yards (914 m) at a speed of up to six knots, and by 1881 the factory was exporting its torpedoes to ten other countries. The torpedo was powered by compressed air and had a explosive charge of gloxyline or gun-cotton. Whitehead went on to develop more efficient devices, demonstrating torpedoes capable of 18 knots (1876), 24 knots (1886) and finally 30 knots (1890).

In 1877 the British Admiralty paid him £15,000 for certain of his developments and he opened a new factory at Portland. The largest Whitehead torpedo was 19 feet (5.8 m) long, 18 inches (457 mm) in diameter and hulled in polished steel or phosphor-bronze, the explosive charge was up to 200 lb (90 kg) of gun-cotton. The air was compressed to around 1,300 lb/in&sup2 (9 MPa) and drove two propellers through a three cylinder Brotherhood engine. Considerable effort was taken in trying to ensure the torpedo self-regulated its course and depth.

Blanco Encalada was the first ship sunk in a military action by a self-propelled torpedo, during the Chilean civil war on April 23, 1891.

Around 1897, Nikola Tesla patented a remote controlled boat and later demonstrate the feasibility of radio-guided torpedoes to the United States military. Radio remote controlled torpedoes remained uninvestigated until the 1960s. During the World War I, torpedoes came to mean self propelled projectiles fired from a ship or submarine. Later, torpedoes were given (homing) guidance systems.

Torpedoes used by the U.S. Navy

The three major torpedoes in the US Navy inventory are the Mark 48 heavyweight torpedo, the Mark 46 lightweight and the Mark 50 advanced lightweight.

Mark 48 Torpedo

The Mk-48 is designed to combat fast, deep-diving nuclear submarines and high performance surface ships. It is carried by all U.S. Navy submarines. The improved version, Mk-48 ADCAP, is carried by attack submarines, the Ohio-class ballistic missile submarines and the Seawolf-class attack submarines. The Mk-48 replaced both the Mk-37 and Mk-14 torpedoes. The Mk-48 has been operational since 1972. Mk-48 ADCAP became operational in 1988 and was approved for full production in 1989.

Mk. 48 is designed to detonate under the keel of a surface ship, breaking the ship's back and destroying her strength.

Mk-48 and Mk-48 ADCAP torpedoes can operate with or without wire guidance and use active or passive homing. When launched they execute programmed target search, acquisition and attack procedures. Both can conduct multiple reattacks if they miss the target. The MK-46 torpedo is designed to be launched from surface combatant torpedo tubes, ASROC missiles and fixed and rotary wing aircraft.

General Characteristics, Mk-48, Mk-48 (ADCAP)

• Primary Function: Heavyweight torpedo for submarines
• Contractor: Gould
• Power Plant: Piston engine; pump jet
• Length: 5.79 m (19 ft)
• Weight: 1545.3 kg (3,434 lb) (MK-48); 1662.75 kg (3,695 lb) (MK-48 ADCAP)

• Diameter: 53.34 cm (21 in)
• Range: Greater than 8 km (5 mi)
• Depth: Greater than 365 m (1,200 ft)
• Speed: Greater than 28 kn (32.2 mi/h, 51.8 km/h)
• Guidance System: Wire guided and passive/active acoustic homing
• Warhead: 292.5 kg (650 lb) high explosive

• Date Deployed: 1972

Mark 46 Torpedo

The Mk-46 torpedo is designed to attack high performance submarines, and is the current NATO standard. In 1989, a major upgrade program began to enhance the performance of the Mk-46 Mod 5 in shallow water. Weapons incorporating these improvements are identified as Mod 5A and Mod 5A(S). The Mk-46 Mod 5 torpedo is the backbone of the U.S. Navy's lightweight ASW torpedo inventory and is expected to remain in service until the year 2015.

General Characteristics, Mk-46 MOD 5

• Primary Function: Air and ship-launched lightweight torpedo
• Contractor: Alliant Techsystems
• Power Plant: Two-speed, reciprocating external combustion; Mono-propellant (Otto fuel II) fueled
• Length: 2.6 m (102.36 in) tube launch configuration (from ship)
• Weight: 234.8 kg (517.65 lb) (warshot configuration)
• Diameter: 32.4 cm (12.75 in)
• Range: 7.3 km (8,000 yd)
• Depth: > 365 m (1,200 ft)
• Speed: > 28 knot (32.2 mi/h, 51.8 km/h)
• Guidance System: Homing mode: Active or passive/active acoustic homing
• Launch/search mode: Snake or circle search
• Warhead: 44.45 kg (98 lb) of PBXN-103 high explosive (bulk charge)
• Date Deployed: 1966 (Mod 0); 1979 (Mod 5)

Mark 50 Torpedo

The Mk-50 is an advanced lightweight torpedo for use against the faster, deeper-diving and more sophisticated submarines. The Mk-50 can be launched from all ASW aircraft, and from torpedo tubes aboard surface combatant ships. The Mk-50 will eventually replace the Mk-46 as the fleet's lightweight torpedo.

General Characteristics, Mk-50

• Primary Function: Air and ship-launched lightweight torpedo
• Contractor: Alliant Techsystems, Westinghouse
• Power Plant: Stored Chemical Energy Propulsion System
• Length: 2.84 m (112 in)
• Weight: 340 kg (750 lb)
• Diameter: 32.4 cm (12.75 in)
• Speed: > 40 kn (46 mi/h, 74 km/h)
• Guidance System: Active/passive acoustic homing
• Warhead: Approximately 45 kg (100 lb) high explosive (shaped charge)

External Links

• US Navy torpedo data cut'n'pasted from a Navy Fact File
• A slightly more recent writeup on the Mk-48 is available at a SSBN 624 web site by Clwyd