BEARING DRIFT The direction of change of a contact’s bearing, i.e., bearing drift is right when the contact moves from 090 to 095.
BEARING RATE The speed (or rate of change) of a contact’s bearing. A contact that has a bearing change from 090 to 095 in one minute has a bearing rate of 5 degrees per minute right.
BIGMOUTH ANTENNA Slang name for the AN/BRA-34 multifrequency antenna. A radio antenna suitable for transmission or reception of several frequencies including HF, VHP, and UHF. Shaped like a telephone pole, it protrudes from the sail about 25 feet.
BILGES The space at the very bottom of the cylindrical hull of a submarine below the lower level deck. In the engineering spaces, the bilges capture leakage from piping systems for pumpout by the drain system. The bilges also capture any water from flooding so that it can be pumped out before it rises above the lower level deck to damage equipment.
BIOLOGICS Ocean noises generated by marine life forms: shrimp, whales, and other fish and mammals fill the sea with clicks, groans, grunts, and even tonals. The sounds can sometimes be mistaken for F’lbmarine sounds. A current theory holds that submarines transiting at low speeds can attract marine animals, thus shrouding the submarine in a cloak of biologies. For this reason, biologies are usually investigated with narrowband sonar to prove they do not hide an enemy submarine.
BLOCKS-OF-WOOD SONAR Code name for a Russian active sonar that sounds like two wood blocks clicking together. Used almost exclusively by Russian submarines to verify a target’s range immediately prior to weapon launch. Immediate action for an American submarine hearing Blocks of Wood sonar is to call a Snapshot.
SLOWDOWN Opening a valve in a pipe from a steam generator (boiler) to the sea to blow out sediment and boiler chemicals. High pressure of the boiler forces the water out to lower pressure of the sea when at fairly shallow depths. Usually done only at periscope depth. Extremely noisy operation that destroys sonar reception completely.
BLOWING SANITARY Application of high pressure air to a sanitary (sewage) tank to force the sewage out of the tank into the sea. The air trapped in the tank must be vented to the inside of the ship to avoid telltale bubbles that could allow the ship to be detected. The venting makes the ship stink.
BLUEOUT Reverberations and noise from the bubbles caused by an underwater nuclear explosion. Masks sonar reception for hours, sometimes days.
BOMB GRADE URANIUM U-235, capable of fissioning and causing nuclear energy release. High concentrations of U235 are used only in nuclear bombs and in high power-density naval reactors.
BOMB (OXYGEN GENERATOR) An electrical device that puts an ultrahigh voltage on distilled water, causing electrolysis, the breakdown of water into hydrogen and oxygen. The oxygen is put into the oxygen banks and bled into the ship for breathing. The hydrogen is discarded overboard through the auxiliary seawater system. The device, making the explosive combination of oxygen and hydrogen, has the potential to explode violently enough to breach the hull and sink the ship. Affectionately nicknamed the Bomb.
BOOMER Nickname for an FBM, fleet ballistic missile submarine. When used by SSN (fast attack submarine) sailors, it can be a derogatory term. A badge of honor to boomer sailors who see themselves as the lone defenders of America.
BOTTOM CONTOUR NAVIGATION Navigation by using a bottom bounce sonar pulse to map the contour of the ocean bottom and comparing the contour to computer memories. When the actual contour matches the computer’s memory, the ship’s position is known and the ship has a “fix.” Advantageous since it allows obtaining a fix when deeply submerged without need to slow down and approach the surface. Disadvantages are that it emits an active sonar beam, allowing detection, and is useless when over a sandy flat bottom.
BOTTOM CONTOUR (BE) SONAR Sonar set allowing bottom contour navigation with a secure pulse (narrow frequency, short pulse duration) sonar.
BOTTOM SOUNDING Distance from the keel to the ocean bottom, measured in fathoms using the fathometer or BE sonar.
BOUNDARY LAYER Region of fluid flow around a solid object where the flow is slowed by friction with the surface of the object. Causes drag, slowing the object.
BOURDON TUBE A bent tube of metal that straightens when increasing internal pressure is applied. Used in primitive depth gages.
BOW COMPARTMENT Furthest forward compartment in a Piranha class submarine, containing crew berthing in the upper level and the emergency diesel generator in the lower level.
BOX A rectangular area of ocean, about ten miles wide and thirty miles long. A transiting submarine is required to stay inside the box. The box moves through the ocean at the same speed as its center, called a PLAIN (point of intended motion). Used so that an ASW surface ship does not mistake a transiting U.S. sub for an enemy. Any submarine contact inside the box is assumed to be a friendly. Not used in wartime, when submarine safety lanes are used, entire lanes devoted to transiting U.S. subs.
BRIDGE Small space at the top of a submarine’s sail used for the Officer of the Deck to control the movement of the ship when on the surface. The height allows a better view of the surroundings of the ship.
BRIDGE ACCESS TRUNK Tunnel from the interior of the submarine to the bridge.
BROADBAND Noise containing all frequencies; white noise, such as heard in radio static, rainfall, or a waterfall. Broadband detection range is high for surface ships, which are noisy. Broadband detection range is low for submarines, usually less than five miles, due to quiet submarine designs.
BUBBLES (1) The ship’s angle in degrees, as in the order “five degree down bubble.” A relic of the days when bubble inclinometers were used to measure the ship’s angle. Modern angle indicators take input from the gyro. The old style bubble is retained as insurance against electrical failures. (2) Control. Loss of control is known in slang as “losing the bubble.”
BULKHEAD Seagoing name for a wall. Compartment bulkheads are the reinforced steel walls between compartments, hardened against seapressure so that one flooded compartment will not flood the neighboring compartment.
BURST COMMUNICATION Satellite-to-submarine and submarine-to-satellite radio transmissions using computers to compress messages. Allows high data rates, so that a ream of messages may be transmitted or received in mere seconds.
BUS Electrical term for a collection of loads. Vital bus loads include reactor main coolant pumps and control rod control. Nonvital bus loads are also “vital” and include sonar, fire-control, etc., but are called nonvital since their loss will not immediately cause the loss of the ship.
CAVITATION Noise generated by a ship’s screw. Always generated on surface ships, but only on submarine screws when a ship accelerates. A screw blade moving in the water, like an airplane wing, causes a low pressure region on one side and a high pressure region on the other. The low pressure (suction) side pulls the ship forward while the high pressure side pushes the ship forward. When the low pressure side’s pressure gets too low, the water actually flashes to steam (boils) since the pressure can no longer keep the water molecules together in liquid form. A steam bubble is formed that is moved out into the water. When the steam bubble sees the higher pressure in the water away from the screw, it collapses again into liquid and emits a loud high frequency screech. A dead giveaway that a submarine is accelerating. To minimize noise, a submarine accelerating does so deliberately slowly. When running from a torpedo, in an emergency, the Conn will order maneuvering to cavitate since speed is more important than stealth.
CHAIN REACTION When a nuclear fission reaction causes at least one more fission reaction from the release of neutrons. The fission neutrons leak when subcritical, but when a reactor is critical, the number of fissions is constant since one reaction leads to another.
CHARGE PUMP A high-pressure pump that forces water into the high-pressure nuclear reactor cooling system to make up for any water lost from a rupture or leak.
CHECK VALVES Valves that allow flow only in one direction.
CHICKEN SWITCH One of two levers in the contr
ol room that emergency blow the main ballast tanks. So named since they are used when the captain is chicken and can no longer remain submerged. A term sometimes used for the hydraulic levers aft that shut ball valves on seawater systems for isolation of flooding.
CHIEF OF THE BOAT (COB) The most senior non-nuclear chief petty officer aboard, who is administratively responsible for the enlisted men on the submarine.
CINCLANTFLEET Commander-in-Chief, U.S. Atlantic Fleet. Admiral in command of the fleet, who has COMAIRLANT, COMSUBLANT, and COMSURFLANT reporting to him. Little known fact: as a CINC, the admiral has nuclear weapon release authority separate from that of the President. He will out of courtesy not release nuclear weapons without Presidential orders, but is authorized to use his own judgment during an emergency. CINCLANTFLEET also is the name for the organization supporting the admiral’s command.
CIRCLE PATTERN Mark 49 and Mark 50 torpedo search pattern in which the torpedo swims in a circle until it finds the target.
CLAMSHELLS The steel or fiberglass hinged plates that cover the top of the bridge cockpit when rigged for dive and are opened when rigged for surface. When shut, the top of the sail is completely smooth.
CLEAR BAFFLES A maneuver to turn the ship around so that the sonar system can examine the conical slice of ocean previously astern of the ship, the blind spot called the baffles.
CLEAR DATUM Tactical euphemism meaning run away.
CLEARANCE Permission from COMSUBLANT for a submarine to submerge and go to a certain place for a certain mission. Also called a SUBNOTE, the clearance specifies the travel of the box and the PLAIN through the ocean.
CLICK A kilometer per hour.
CLUTCH A device aft of the reduction gear that allows uncoupling the ship’s drive train (main engines and reduction gear) from the shaft, allowing the EPM (emergency propulsion motor) to turn the shaft, and hence the screw, without having to turn the massive main engines. Very similar to the clutch on an automobile.
CO BURNER/CARBON MONOXIDE BURNER A device that combusts carbon monoxide to produce carbon dioxide. CO is able to knock a crew unconscious with low concentrations, so the burners are vital pieces of the atmosphere control equipment.
C02 SCRUBBER Atmospheric control equipment that rids the ship of carbon dioxide (from breathing, the diesel, and the CO burner) by blowing it over an amine bed.
COCKPIT The small space at the top of the sail. The bridge.
COMAIRLANT Admiral in command of Naval Aviation in the Atlantic Fleet.
COMMINT Intelligence gained from intercepted enemy communications.
COMMODORE Commander of a squadron of submarines. Usually a Navy captain. For a few years, the old rank of commodore was recommissioned, and commodore was essentially a one star admiral. The admirals complained, wanting to be called admirals. In recent years the rank of commodore has been replaced with the rank rear admiral (lower half).
COMPARTMENT A section of a submarine with hardened bulkheads and the pressure hull as its envelope. Able to withstand almost full crush depth pressure. Separating a submarine into several compartments makes the ship more survivable.
COMSUBLANT Commander Submarines U.S. Atlantic Fleet, the admiral in command of the Atlantic’s submarine force. Also the name of the organization that supports the admiral, including intelligence, liaison, supply, communications, and procurement.
COMSUBRON 7 Commander of Submarine Squadron Seven. Also the name of the organization that supports the commodore.
SUBRON’s physical command includes pier 7 at Norfolk Naval Base and the submarine tender ship Hercules. The Squadron staff and the commodore occupy several 0-level decks of the Hercules.
COMSURFLANT Commander Surface Force U.S. Atlantic Fleet, the admiral in command of the Atlantic’s surface fleet. Also the name of the organization that supports the admiral.
CONDENSER A piece of equipment that converts low pressure steam to water by passing the steam over tubes with cold seawater flowing inside them. The main seawater system exists to pump the seawater through the truck-sized main condensers. The condensate water is pumped back into the steam generators (boilers) to be boiled to steam for use in the turbines for power production and propulsion.
CONN (1) The act of directing the motion and mission of a submarine. Done by the Officer of the Deck, the Junior Officer of the Deck, or the captain. Whoever has the Conn is the conning officer. (2) The elevated periscope stand in the control room where the Officer of the Deck usually conns the submarine.
CONN OPEN MICROPHONE RECORDER (COMR) A black box in the overhead of the control room that records conversations during sensitive operations for use of reconstruction. Submitted with patrol reports after an OP. Monitored in the radio room and sometimes in sonar.
CONNING TOWER The fin on top of a submarine’s hull allowing the ship to be conned safely on the surface. Called the sail in the U.S. Navy.
CONTACT Another ship, detected by visual means, sonar, or radar. A contact can be hostile or friendly.
CONTINGENCY 12 A section in the CINCLANTFLEET SIOP WARPLAN outlining options for a submarine captain when he suspects the United States has been the victim of a decapitation nuclear assault. Boomers and Javelin cruise missile submarines are given the option of launching nuclear weapons at the enemy without orders from Washington, NMCC, or CINCLANTFLEET. Fast attack submarines without land attack weapons are given the option of attacking enemy surface ships and submarines without further orders.
CONTROL COMPARTMENT Bubbleshaped compartment above the main pressure hull of some Russian submarines, where all control activities are centered.
CONTROL ROOM Nerve center of a submarine, where the depth, speed, and combat actions of a submarine are directed.
CONTROLLING ROD GROUP The group of nuclear control rods that are raised and lowered to control reactor temperature or dropped to the bottom of the core during a partial (group) scram.
COOLANT DISCHARGE Discarding reactor coolant (water) overboard. Done during the heatup of a fast recovery startup, when the raising of water temperature from 300 degrees to 500 degrees makes it expand dramatically.
COOLANT LOOP One of two piping loops going from the reactor vessel to the loop’s steam generator (boiler) and then to the loop’s reactor main coolant pumps and back to the reactor vessel. The piping is called the primary coolant system and is highly radioactive, CORE The inside of the reactor’s pressure vessel. The core contains fuel elements including enriched (bomb grade) uranium sheathed in zirconium metal; a moderator to slow down the fission neutrons so they can be absorbed by uranium nuclei to cause more fissions (water is the moderator in a Navy core); and control rods that absorb neutrons so that the reactions and power level can be controlled.
COSMOS Russian communications satellite.
COUNTER ROTATING SCREWS Propulsion method using a screw that turns clockwise with another coaxial screw that turns counterclockwise. Efficiency increased since the first screw’s exit vortex energy is used by the second screw to create more thrust. Disadvantages include complexity of design.
COUNTERDETECTION When submarine A sneaks up on submarine B, the detection by submarine B of submarine A is a counterdetection.
COUNTERFIRE When submarine A fires on submarine B, a counterfire is the launching of a weapon by submarine B at submarine A. COUNTERMEASURES A small object launched by a signal ejector or a torpedo tube designed to decoy an incoming torpedo. Some low-tech countermeasures are bubble generators designed to fool active sonars. More sophisticated countermeasures for use against passive sonar torpedoes are torpedosized noisemakers programmed with the firing ship’s own sound signature, broadcast louder than the firing ship.
COW (CHIEF OF THE WATCH) Member of the ship control team manning the Ballast Control Panel.
CPA (CLOSEST POINT OF APPROACH) The closest range a tracked contact will come to own ship. Prior to CPA the contact is closing. After CPA the contact is opening.
CPO (CHIEF PETTY OFFICER) Enlisted rank somewhat equivalent to sergeant
in the Army. Possesses infinite knowledge and wisdom regarding submarines.
CRAZY IVAN A Russian submarine’s maneuver to clear baffles. Due to the Russian submarines frequently being trailed by U.S. subs, the Russians clear baffles suddenly and come back on the reciprocal course. An intimidation tactic designed to deter American boats from trailing too close. The cause of several undersea collisions.
CREEP Property of some metals at elevated temperatures to stretch when failing instead of rupturing or fracturing. Titanium has the property of exhibiting creep at low temperatures.
CREEP DEPTH A titanium submarine’s depth at which the hull begins to fail in creep.
CRITICAL The point that a nuclear reactor’s fission rate is constant without an external source of neutrons. The chain reaction keeps fissions going on using neutrons from fissions.
CRUSH DEPTH The depth that a pressure hull ruptures from seawater pressure.
CSLINST COMSUBLANT Instruction. An administrative document with administrative orders from COMSUBLANT.
CURVE A curve is obtained when a fire-control solution is reached. Derives from the days of manual plots when bearing to a target was plotted against time. After two or three legs, the Z-shaped curve defined a solution to the target.
CUTBACK An automatic reactor protection circuitry action to lower reactor power by driving the controlling control rod group into the core. The cutback allows propulsion to continue while saving the reactor from an overpower meltdown accident. A Navy engineering compromise action between a scram (which eliminates propulsion) and continued criticality, which could lead to a nuclear accident.
CUTBACK OVERRIDE Action to stop a cutback by taking the mode selector switch to the cutback override position, stopping control rod motion inward. Used when a cutback is caused by an instrument failure rather than an actual hazard.
C.O. (COMMANDING OFFICER) Official title of the captain of a ship.
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