Voyage of the Devilfish

DOPPLER EFFECT Effect responsible for train whistles sounding shrill when the train approaches and low pitched when the train is past. When a moving platform emits sound waves, the waves are compressed ahead and rarefacted (spread apart) behind the source. The compression of the waves raises their frequency, making a higher note.

DOPPLER FILTER A sonar receiver that blanks out reception of the frequency of transmission of a sonar pulse. The receiver listens only for higher or lower frequency returns, thus screening out stationary contacts and only detecting moving contacts. Used in police radars and torpedo underice active sonars.

DOT STACK Same as a bearing dot stack.

DOUBLE HULL Construction of the pressure hull inside an outer hull. The space between the outer and inner hull is used for equipment and ballast water. Creates a very survivable platform at the cost of weight and expense.

DRAIN PUMP Main component of the drain system. Pumps out bilges of flooding spaces and discharges the water overboard.

DUTY OFFICER Essentially the Officer of the Deck when the ship is tied up at the pier or in drydock.

D/E (DEFLECTION/ELEVATION) The spherical array of the BAT-EARS sonar suite has hydrophone sonar receivers placed over most of its surface. A sound received on the upper surface (high D/E angle) means the contact is above the submarine or its noise is bouncing off the ocean above. A sound received at low D/E is either reflected from the ocean bottom or directly transmitted from beneath the submarine.

ELECTRIC PLANT CONTROL PANEL (EPCP) A console in the maneuvering room that controls the electrical distribution of the ship including the turbine generators and the battery.

ELF (EXTREMELY LOW FREQUENCY) Long wave radio waves capable of penetrating deeply into the ground and underwater. Requires large high power land based antennae and has very low data rates (taking several minutes to transmit one letter or number). Usually used to call a submarine up to periscope depth to receive a burst of communication from the satellite.

EMBRITTLEMENT A reactor’s pressure vessel is impacted by trillions of neutrons, altering the physical structure of the metal. The steel vessel becomes brittle and fractures easily when subjected to sudden temperature changes, like a frozen coffee mug shatters when hot coffee is poured in.

EBMT BLOW Emergency main ballast tank blow.

EMERGENCY BLOW Blowing the water out of the main ballast tanks using ultrahigh-pressure air. Empties ballast tanks in seconds, lightening the ship, allowing the ship to get to the surface in an emergency such as flooding.

EMERGENCY COOLING (XC) A system that uses a seawater heat exchanger to cool the nuclear reactor when flow through the core is lost. Uses natural convection flow, which is flow motivated by the tendency of hot water to rise and cold to sink.

EMERGENCY DEEP An emergency procedure used at periscope depth to avoid collision with a surface ship. Involves cavitating, flooding a depth control tank, and putting a diving angle on the ship to get deep in mere seconds. Designed to avoid hull rupture from collision with a surface ship that cannot see the sub at PD. Era of super tankers makes this a vital procedure because super tankers have so much oil volume forward of their engines that they are quiet as a sailboat and are often undetected by sonar.

EMERGENCY HEATUP RATE Emergency procedure used on startup when heating a nuclear reactor after a scram. Instead of a nice slow warmup at a half degree per minute or one degree per minute, the plant is heated up at up to several hundred degrees per minute to save the ship, ignoring the risk of a possible vessel rupture from thermal stress.

EMERGENCY PROPULSION MOTOR (EPM) A large DC motor aft in the engineroom, capable of turning the shaft to achieve 3 knots using battery power alone. An electricity hog.

EMERGENCY SSTG WARMUP Emergency procedure to get a turbine generator to make power within seconds from its cold condition after a reactor scram. Done to achieve power quickly, ignoring the risk of turbine destruction, case rupture, and major steam leak.

ENGINEROOM Largest and furthest aft compartment on a U.S. submarine. Holds the maneuvering room, propulsion and electrical turbines, main condensers, numerous pumps, evaporator, air conditioners, reduction gear, clutch, EPM, and shaft seals.

ENSIGN Lowest officer rank. Also a flag flown aft when the ship is tied up.

EO (ELECTRICAL OPERATOR) Enlisted nuclear qualified watchstander who mans the Electric Plant Control Panel and reports to the EOOW.

EOOW (ENGINEERING OFFICER OF THE WATCH) Nuclear qualified officer who runs the nuclear power plant. Responsible to the OOD for propulsion and propulsion plant damage control.

ESCAPE POD Device used on Russian submarines to escape a sinking ship.

ESCAPE TRUNK A spherical airlock used on American nuclear submarines. The device can be used to make emergency exits from a sub sunk in shallow water. Principally used for divers to lock in or lock out.