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 control 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.