Voyage of the Devilfish

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.

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.