CK 034 Multifunction search periscope on Royal Navy SSNs.
Clyde U.S. Navy nickname for the auxiliary diesel engine.
CO Commanding Officer. Title given to an officer in command of a ship. Often called 'Captain' or 'Skipper.'
COB Chief of the Boat. Senior enlisted man in the submarine's crew. Usually a senior or master chief petty officer. Interfaces directly with the XO on issues that affect the enlisted personnel. The Royal Navy equivalent is the coxswain.
COMINT COMmunications INTelligence.
COMSUBLANT COMmander, SUBmarine Force AtLANTic.
COMSUBPAC COMmander, SUBmarine Force PACific.
Conform Name of a Navsea-designed SSN in competition with Admiral Rickover's 688 design.
Control room Area on a U.S. Navy submarine where the submarine's ship control, fire control, and periscopes are located. All major submarine functions are controlled from this location. The OOD stands his watch here when the submarine is submerged. In communications the area is referred to as the conn.
Convergence Zone (CZ) Phenomenon whereby, if the water is deep enough, water pressure turns sound waves up toward the surface. This occurs at intervals of roughly 30 nautical miles. Multiple CZ contacts are possible when the sound bounces off the surface and heads back down, eventually to be turned back upward again by the pressure.
COW Chief of the Watch. Leading enlisted man in control during a watch. Operates the ballast control panel to dive and surface the submarine and makes trim corrections when directed by the diving officer.
CVBG Aircraft Carrier Battle Group.
Delta I to IV SSBNs The Russian Delta series of SSBNs is an ongoing variant of the basic Yankee-class SSBN design. Almost all variations are determined by the type of SLBM being carried. The latest variant, the Delta IV, also incorporates quieting and sensor enhancements. A total of forty-three Deltas have been built.
Direct path Term used to describe the route that sound waves take from noise source to sonar system without interacting with the surface or the ocean floor. Roughly speaking, it is considered to be the straight-line distance between the two vessels.
DNR Director, Naval Reactors
Dolphins Symbol of the submarine force in just about every nation. Also, the badge or pin that designates a sailor as qualified in submarines.
DSMAC Digital Scene-Matching Area Correlation. A second Tomahawk land attack missile navigation system used to improve the accuracy of the conventional variants. Uses a cameralike system to make detailed digital pictures of the terrain and compares them with stored images in the guidance computer.
DSRV Deep-Submergence Rescue Vehicle. A small rescue submersible designed to dock with a sunken submarine and retrieve the crew.
EAB Emergency Air Breathing system. A low-pressure air system that crewmen can plug in to and obtain breathable-although dry-air. This system is to provide a source of air while a submarine ventilates to get rid of the smoke from a fire.
Echo SSN A first-generation Soviet nuclear-powered submarine, it originally was designed as an SSGN (Echo I class), but the tubes were removed and the units converted to SSNs. These submarines were noisy and had extremely unsafe radiation problems. All have been retired because of their poor safety record. A total of six units were built.
Electric Boat Company The company started by John Holland to produce submarines for the U.S. Navy. Presently owned by General Dynamics Corporation.
ELF Extremely Low Frequency radio band.
Emergency blow Process by which high-pressure air is rapidly introduced directly into the submarine's main ballast tanks. An emergency blow makes the submarine positively buoyant, and it will rise to the surface quite quickly. This system was instituted as part of the Subsafe program following the loss of the USS
Enigma World War II German communication cipher (encryption) system.
EOOW Engineering Officer of the Watch. Officer in charge of the team that is monitoring and manipulating the submarine's reactor and propulsion system. Key responsibility is to maintain propulsion in a safe manner.
ESM Electronic Support Measures. A passive receiver system designed to detect radar emissions from aircraft and surface ships.
Exocet Antiship cruise missile made by the French firm Aerospatiale. Slightly smaller than a Harpoon but just as deadly.
Fairwater U.S. Navy term for the sail on a submarine. The Royal Navy uses the term
Familygrams Short (forty to fifty words) messages that U.S. Navy submariners receive from family members about once a week while on patrol.
FBM Fleet Ballistic Missile submarine.
First lieutenant The Royal Navy equivalent of a U.S. Navy executive officer. Often referred to as 'Number
