LMRS: Long-term Mine Reconnaissance System: A remote-controlled self-propelled probe vehicle, launched from a torpedo tube and operated by the parent submarine. The LMRS is designed to detect and map enemy minefields or other undersea obstructions, and is equipped with forward and side-scanning sonars and other sensors. Each LMRS is retrievable and reusable.
MAD: Magnetic Anomaly Detection. A means for detecting an enemy submarine by observing its effect on the always-present magnetic field of the earth. Iron anywhere within the submarine (even if its hull is nonferrous or de-Gaussed) will distort local magnetic field lines, and this can be picked up by sensitive magnetometers in the MAD equipment. Effective only at fairly short ranges, often used by low-flying maritime patrol aircraft. Some naval mine detonators also use a form of MAD by waiting to sense the magnetic field of a passing ship or submarine.
Megaton: a measure of power for strategic nuclear weapons. One megaton equals the explosive force of one million tons of TNT. (A megaton also equals one thousand kilotons.)
METOC: Meteorology and Oceanography Command. The part of the U.S. Navy that is responsible for providing weather and oceanographic data, and accompanying tactical assessments and recommendations, to the navy’s operating fleets. METOC maintains a network of centers around the world to gather, analyze, interpret, and distribute this information.
Naval Submarine League (NSL): A professional association for submariners and submarine supporters. See their Web site, www.navalsubleague.com.
Network-centric warfare: a new approach to war fighting in which all formations and commanders share a common tactical and strategic picture through real-time digital data links. Every platform or node, such as a ship, aircraft, submarine, Marine Corps or army squad, or SEAL team, gathers and shares information on friendly and enemy locations and movements. Weapons, such as a cruise missile, might be fired by one platform and redirected in flight toward a fleeting target of opportunity by another platform, using information relayed by yet other platforms — including unmanned reconnaissance drones. Network-centric warfare promises to revolutionize command, control, communications, and intelligence, and greatly leverage the combat power of all friendly units while minimizing collateral damage.
NOAA: National Oceanic and Atmospheric Administration. Part of the Department of Commerce, responsible for studying oceanography and weather phenomena.
Ocean Interface Hull Module: part of a submarine’s hull that includes large internal “hangar space” for weapons and off-board vehicles, to avoid size limits forced by torpedo-tube diameter. (To carry large objects such as an ASDS minisub externally creates serious hydrodynamic drag, reducing a submarine’s speed and increasing its flow noise.) The first Ocean Interface has been ordered as part of the design of the USS
PAL: Permissive Action Lock. Procedures and devices used to prevent the unauthorized use of nuclear weapons.
Photonics mast: the modern replacement for the traditional optical periscope. The first will be installed in the USS
Piezo rubber: a hull coating that uses rubber embedded with materials that expand and contract in response to varying electrical currents. This permits piezo-rubber tiles to be used to help suppress both a submarine’s self-noise and echoes from enemy active sonar (see
Pump jet: a main propulsor for nuclear submarines that replaces the traditional screw propeller. A pump jet is a system of stator and rotor turbine blades within a cowling. (The rotors are turned by the main propulsion shaft, the same way the screw propeller’s shaft would be turned.) Good pump-jet designs are quieter and more efficient than screw propellers, producing less cavitation noise and less wake turbulence.
Quieting: design techniques and technologies used to minimize the amount of noise a submarine transmits into the surrounding water. Since quieting is crucial to stealth, the most advanced methods are highly classified. Techniques include placing internal decks on “rafts” that float on springs or flexible pivot joints in order to isolate internal sounds and vibrations from the outer hull. Equipment may also be mounted on noise- insulating materials, such as rubber blocks or bladders filled with oil. Quieting can also include disciplined behavior by the submarine’s crew, for instance not slamming hatches, not dropping tools on the deck, and not operating some devices or equipment at all when quieting is most essential.
Radiac: Radiation Indications and Control. A device for measuring radioactivity, such as a Geiger counter. There are several kinds of radiac, depending on whether alpha, beta, or gamma radiation, or a combination, is being measured.
ROEs: Rules of Engagement. Formal procedures and conditions for determining exactly when weapons (including “special weapons” such as nuclear devices) may be fired at an enemy.
SEAL: Sea Air Land. U.S. Navy Special Warfare commandos. (The equivalent in the Royal Navy is the SBS, Special Boat Squadron.)
7MC: a dedicated intercom line to the Maneuvering Department, where a nuclear submarine’s speed is controlled by a combination of reactor-control-rod and main steam-throttle settings.
Sonobuoy: a small active (“pinging”) or passive (listening-only) sonar detector, usually dropped in patterns (clusters) from an aircraft or a helicopter. The sonobuoys transmit their data to the aircraft by a radio link. The aircraft might have on-board equipment to analyze this data, or it might relay the data to a surface warship for detailed analysis. (The aircraft will also carry torpedoes or depth charges in order to be able to attack any enemy submarines that its sonobuoys detect.) Some types of sonobuoy are able to operate down to a depth of sixteen thousand feet.
SOSUS: Sound Surveillance System. The network of undersea hydrophone complexes installed by the U.S. Navy and used during the Cold War to monitor Soviet submarine movements (among other things). Now SOSUS refers generically to fixed-installation hydrophone lines used to monitor activities on and under the sea. The Advanced Deployable System (ADS) is one example: disposable modularized listening gear designed for rapid emplacement in a forward operating area. After the Cold War, some SOSUS data has been declassified, proving of immense value for oceanographic and environmental research.
Sound-ray traces: a display of the paths in which spreading sound waves will be bent and reflected underwater in a particular area. Ray traces are estimates, based upon calculations using information on local ocean temperature and salinity at different depths. Sound-ray trace information can be used to help a
