12.75 inch Mark 46 (324 mm)

12.75 inch Mark 46 (324 mm) captured in-flight

Description

The 12.75 inch Mark 46 is an American lightweight anti-submarine torpedo introduced in 1963 (in Mod 0 variant), which was quickly replaced in 1967 by Mod 1, addressing initial issues with the propulsion system. Torpedo has seen a series of upgrades until the replacement arrived in 1990 - the Mark 50 Barracuda. Still, struggling with high cost, the Mark 46 received Service Life Extension Programme, and eventually new, cheaper, derivative, the Mark 46 Mod 8, was being developed in 1994 merging the two torpedoes into what eventually became the Mark 54 torpedo, finally replacing the Mark 46 series in 2004.

Vehicles equipped with this weapon

• Chikugo

General info

Tell us about the tactical and technical characteristics of the torpedo.

Effective damage

Describe the type of damage produced by this type of torpedo (high explosive, splash damage, etc)

Comparison with analogues

• SET-40 (400 mm) - A Soviet lightweight anti-submarine torpedo. Compared to the Mark 46, it is much slower but has almost double the explosive mass and a slightly longer range

Usage in battles

Characteristic blunt nose of the Mark 46, and a triple launcher on Chikugo (here in the Sea Biathlon event camouflage)

As submarines are not in War Thunder, the Mark 46 will have to be used against surface ships, which with its pathetic explosive mass of 44.5 kg means it will only be effective on boats or sub-chasers. Because it cannot destroy most ships in a single hit, it should be used in conjunction with gun fire to destroy ships. You can soften up targets first by setting them on fire and disabling weapons, before launching a few torpedoes to finish it off, or use it to disable a ship's engines first, and then dissect it with the main battery.

Pros and cons

Pros:

• Very fast speed of 91 km/h, can be somewhat reliably used against fast vessels

Cons:

• Tiny explosive mass of 44.5 kg, a destroyer can tank a full salvo of 3 torpedoes

History

The Mark 46 was born out of the need for a torpedo that could handle latest soviet submarines, something Mark 44 couldn't. Feasibility studies begun in December 1956, leading to the requirements being issued in November 1960. After 3 years of development, the production of the Mark 46 Mod 0, has begun in 1963.

The Mark 46 Mod 0 was manufactured by the Aerojet-General Corporation and was notable for being the first high-performance, thermal-powered torpedo in US Navy service. It was "thermal powered" for the solid fuel it used, which burned releasing high-pressure gasses that powered the torpedo and proved to be more energy-dense than the battery-electric propulsion. The system, however, proved very difficult to maintain.

The Mark 46 Mod 1 introduced in April 1967 aimed to address the maintainability concerns. The Mod 1 switched to using a monopropellant fuel based on propylene glycol dinitrate, named Otto fuel, which was an oily substance that could burn without any oxidiser, being more energy-efficient than either the battery-electric or even the previously used solid fuel, leading to an increased the range and speed of the torpedo, while also being much cheaper to maintain. Honeywell Incorporated was asked to become a second production source for the torpedo.

Further enhancements led to the development of the Mark 46 Mod 2, which entered service in 1972. This version incorporated a new course gyro and presetter, and most Mod 1 torpedoes were upgraded to Mod 2 standard by 1975. The Mod 2 featured improved performance for ship-launched versions and was optimised for use from helicopters equipped with dipping sonars, allowing operations within a 360-degree radius. It also became the standard of torpedoes used by the ASROC launchers at the time. Together with the launching component it was designated RUR-5A ASROC Mod. 4. Overall, Mod 2 was adopted by 23 countries, de-facto becoming NATO's standard anti-submarine warfare torpedo at the time.

One of the Mark 46 Mod 2 torpedoes was recovered by a Chinese fishermen in 1978, and over the next decade its design was reverse-engineered into a Yu-7 torpedo (鱼-7, meaning Fish-7), which entered testing in 1988 and production in 1990. It used Otto fuel II for propulsion.

Attempts to develop a Mark 46 Mod 3 variant were abandoned in 1972. The Mark 46 Mod 4 was developed in 1973 as the payload for the CAPTOR anti-submarine mines, with an improved version becoming the Mod 6.

In October 1972 the Near-Term Improvement Programme (Neartip) was initiated. This programme aimed to enhance the torpedo's acoustic performance, countermeasure resistance, and guidance systems by incorporating CMOS integrated circuits. It culminated in the Mark 46 Mod 5, which entered production in July 1979. From 1981 onwards, the Mod 5 became the main version of the torpedo, available both: as new-builds and as upgrades for existing Mod 2 torpedoes. The Mod 5 introduced an advanced digital computer control system and a new passive/active sonar, significantly improving its capabilities in various acoustic environments, including shallow waters. Production under licence began in Japan by Mitsubishi Heavy Industries in 1982, and the Mod 5 was selected by nine additional countries.

With the further increase of the importance of engaging slow-moving or littoral targets, the Mark 46 Mod 5A and Mod 5A(S) were developed in the mid-1980s, entering service in 1989. The Mod 5A(S) was capable of operating in waters as shallow as 40 metres. In October 1996 the Mod 5A(SW) was introduced, being an upgrade of the older torpedoes to the standards set by the new Mod 5A(S).

Mark 46 Mod 7 was planned to improve the passive sensors, but it was cancelled before completing the development.

Mark 49 received Service Life Extension Programme, and eventually new, cheaper, derivative, the Mark 46 Mod 8, was being developed in 1994 merging the two torpedoes into what eventually became the Mark 54 torpedo, finally replacing the Mark 46 series since 2004 in the US service. Overall, over 26,000 units of Mk 46 were produced, operated by 37 countries and deployed from various platforms, including ships, fixed-wing aircraft, and helicopters. The torpedo became a worldwide success and will likely remain in use for a significant amount of time, even as the Mark 54 becomes increasingly widely adopted.

Media

Excellent additions to the article would be video guides, screenshots from the game, and photos.

See also

• 12.75 inch Mark 44 (Predecessor)

External links

• [Wikipedia] Mark 46 torpedo
• [Federation of American Scientists: Military Analysis Network] MK-46 Torpedo
• Janes Naval Weapon Systems
• [Opisy Broni] Torpeda Mark 46 (in Polish)
• [NavWeaps] United States of America - ASROC RUR-5A and VLA