Russia is seeking to further bolster its sub-surface capabilities, with new generations of conventional and nuclear propulsion submarines, which promise to be significantly more difficult to detect and track for western naval forces. This includes the Yasen, Lada, and Kalina classes of submarines. In recent times, Russia has also demonstrated its growing capability to perform land attack missions with submarines. In December of 2015, a Russian submarine in the Mediterranean fired Kalibr missiles against land targets in Syria.
The U.S. Navy is now prototyping a new, longer range and more lethal submarine-launched heavyweight Mk 48 that can better destroy enemy ships, subs and incoming weapons at longer ranges, service officials said. Lockheed Martin developed the new version of the Mk-48 under a five-year $425 million contract that was awarded in 2011. Torpedoes are self-propelled guided projectiles that operate underwater and are designed to detonate on contact or in proximity to a target. For the U.S. Navy, the modern torpedo enables submarines to defeat surface and undersea threats and gives surface ships and aircraft the means to reach beneath the surface and attack submarines.
The earlier version, the Mk 48 Mod 6, has been operational since 1997 – and the more recent Mod 7 has been in service since 2006.The Mk-48 torpedo is designed to be launched from submarine torpedo tubes. The weapon is carried by all U.S. Navy submarines, including Ohio-class ballistic missile submarines and Seawolf-, Los Angeles-, and Virginia-class attack submarines. It is also used on Canadian, Australian, Brazilian and Dutch submarines.
Lockheed Martin will provide the U.S. Navy the latest advancements in sonar systems under a contract valued at up to $425 million for guidance and control systems for the MK 48 Mod 7 torpedo. Compared to older versions of the venerable Mk-48, the new modular Mod 7 variant increases sonar bandwidth. It can transmit and receive pings over a wider frequency band and it takes advantage of broadband signal processing techniques to greatly improve the weapon’s search, acquisition and attack effectiveness. The torpedo’s seeker has an active electronically steered “pinger” (2D phased array sonar) that helps avoid having to maneuver as it closes with the target.
The three major torpedoes in the Navy inventory are the Mark 48 heavyweight torpedo, the Mark 46 lightweight and the Mark 50 advanced lightweight. The lightweight torpedo gives surface ships, airplanes, and helicopters the means to destroy threat submarines.
A Mk 48 torpedo is 21 inches in diameter and weighs 3,520 pounds; it can destroy targets at ranges out to five miles and travels at speeds greater than 28 knots. The weapon can operate at depths greater than 1,200 feet and fires a 650-pound high-explosive warhead. The MK 48 is propelled by a piston engine with twin, contra-rotating propellers in a pump jet or shrouded configuration. The engine uses Otto fuel propulsion system, a liquid monopropellant fuel,that decomposes into hot gas when ignited, which drives the engine. The thrust is generated by a propulsor assembly
The MK 48 has a sophisticated guidance system permitting a variety of attack options. As the torpedo leaves the submarine’s launch tube a thin wire spins out, electronically linking the submarine and torpedo. This enables an operator in the submarine, with access to the submarine’s sensitive sonar systems, initially to guide the torpedo toward the target. This helps the torpedo avoid decoys and jamming devices that might be deployed by the target. The wire is severed and the torpedo’s high-powered active/passive sonar guides the torpedo during the final attack. The MK48 Mod 5, with its improved guidance system, and the MK48 Mod 6 with low noise propulsion, provide the fleet with torpedoes whose performance is unmatched in deepwater scenarios.
The Mk48 Mod 7 Common Broadband Advanced Sonar System (CBASS) torpedo is optimized for both the deep and littoral waters and has advanced counter-countermeasure capabilities. The Common Broadband Advanced Sonar System (CBASS) upgrades to ADCAP will extend the current sonar array on the weapon into a broadband mode and improve the onboard signal processing to provide enhanced operation against countermeasures and diesel submarines operating in the littorals. “This provides streamlined targeting and allows the torpedo to transmit and receive over a wider frequency band,” Tom Jarbeau, Director and General Manager of Targets, Torpedoes and Sensors, Lockheed Martin, said.
The submarine missions now increasingly take place in shallow-water littoral areas. The Chief of Naval Operations continues to stress shallow water (less than 600 feet) as a critical operating area to counter third world diesel electric submarines. Acoustic reverberation, poor sound propagation, local ship traffic, false targets, and bottom clutter all make torpedo operations more difficult in this noisy operating environment.
MK-48 and MK-48 ADCAP torpedoes can operate with or without wire guidance and use active and/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 earlier MK 48 Mod 5 ADCAP torpedo was an improvement to the MK 48 submarine launched torpedo. The ADCAP enhancement included all digital guidance and control systems, digital fuzing systems, and pro-pulsion improvements which add speed, depth, and range capability. The ADCAP version, in comparison with earlier MK 48 torpedoes, has improved target acquisition range, reduced vulnerability to enemy countermeasures, reduced shipboard constraints such as warmup and reactivation time, and enhanced effectiveness against surface ships.
In 2015 the USN announced plans to restart production and seek a more modular design. “ In the torpedo restart, we are going to be making this a truly modular design that you can pull out a section and plug in different payloads or different propulsion systems or different fuel supplies, and so as you’re developing the payloads you ought to be thinking about how you integrate with the modular Mk 48 some new capabilities and the like,” Program Executive Office for Submarines Executive Director George Drakeley said.
References and Resources also include: