The US Navy’s Mk 48 (or Mark 48) is a heavyweight acoustic-homing torpedo designed to destroy enemy warships and merchant vessels. It has a sophisticated sonar, an all-digital guidance and control system, a digital fusing system, and a robust propulsion system.
The Mark 48, A History
The Navy’s submarine force attack and missile boats are built around the Mk 48 heavyweight torpedo.
Introduced in 1972, the Mk 48 was designed to allow SSNs with enough stealth and speed to defeat the Soviet Navy in the open ocean by closing with and destroying even the most capable Soviet capital warships and antisubmarine warfare (ASW) platforms.
The warhead is designed to strike the keel of a warship, breaking its back, as shown in the video. The Navy was conducting a SINKEX, where they studied the weapons’ effects by sinking retired US warships.
The Mark 48 torpedo is the final weapon that hits the warship in the video. And it breaks the ship in half.
The torpedo has undergone several changes and enhancements during its service lifetime, establishing itself as the universal torpedo for US submarines.
Conceived in the mid-1950s during the pre-digital era, the Mk 48 was pioneering in its use of multi-speed propulsion. This innovative design allowed the torpedo to achieve high transport speeds while wire-guided and then reduce speed to effectively home in on its target.
Mark 48: Lockheed Martin Gets $245 Million Contract For Upgrades
The Navy extended Lockheed Martin’s MK 48 Guidance and Control (G&C) program contract by $245 million.
This contract extension, announced in December, focuses on enhancing the Mod 7 version of the MK 48 submarine-launched torpedo, widely regarded as one of the most capable weapons in the world.
The Mark 48 Torpedo Is a Beast
The Mod 7 variant, developed jointly by the US and Royal Australian Navies, features a high-explosive 650-pound warhead capable of sinking surface ships and submarines.
At high speed, the torpedo can reach speeds of 65 mph.
The Mk 48’s modular design allows easier digital guidance system software updates. This is an important feature, as it enables weapons systems to remain in mission-capable service for extended periods.
The 21-inch (533 mm) submarine-launched weapon is one of the most complex torpedoes ever developed. The Advanced Capability (ADCAP) variant remains the US Navy’s sole submarine-launched torpedo deployed across all US submarines, including strategic missile submarines, as a critical self-defense weapon.
Internally, it consists of a nose group, warhead group, control group, fuel tank group, and afterbody.
The nose group consists of the Mark 72 transducer, the Mark 83 transmitter, the Mark 68 receiver, and the Mark 1 Homing Control Logic (HCL). The transducer unit is in the front of the nose to transmit and receive acoustic signals, the acquisition range being two nautical miles (3600 m).
The receiver in the lower half of the nose group processes acoustic data and determines the target location to generate steering commands.
The HCL at the rear of the nose group and above the receiver contains the computer that directs torpedo maneuvers in the search, homing, and re-attack modes. It is also used to analyze all acoustic signals for valid target returns.
The warhead group consists of the Mark 107 PBXN warhead, the Mark 21 exploder, the Mark 2 arming device, and the Mark 12 electronic assembly. The 292.5 kg warhead has the Mark 21 and the Mark 2 within it, the fuze possessing contact and long-/short-range proximity functions. The Mark 12 electronic assembly at the compartment’s rear contains target detection electronics that detonate the warhead.
The command control unit in the lower third of the control group compartment implements fire control instructions, maintains the torpedo’s speed, and ensures the weapon stays within the maximum and minimum depth limits.
The gyro control unit in the center of the compartment converts steering commands into fin deflection signals while the PCU controls the torpedo’s speed.
The fuel tank group houses the Otto monopropellant fuel (968 pounds) and the wire dispenser used for command guidance after launch.
Virginia-Class. Image Credit: Creative Commons.
The afterbody contains the 500-horsepower external combustion gas piston engine, steering control surfaces, and engine accessories.
The MK 48 is operational across the US submarine fleet and used by Canadian, Netherlands, Brazilian, and Taiwanese navies, demonstrating its global impact.
Author Information and Expertise
Steve Balestrieri is a 19FortyFive National Security Columnist. He served as a US Army Special Forces NCO and Warrant Officer. In addition to writing for 19FortyFive, he covers the NFL for PatsFans.com and is a member of the Pro Football Writers of America (PFWA). His work was regularly featured in many military publications.
