TRIM SYSTEM The piping network, tanks, and trim pump used to establish a good trim. Can be cross-connected to the drain system as a backup for the drain pump.
TRIP The actuation of an interlock, such as a reactor scram.
TURBINE A mechanical rotating device with blades that converts the pressure energy, velocity energy, and internal (temperature) energy of a fluid stream (steam or combustion gases) into mechanical power.
TWO THIRDS SPEED An engine order between All Ahead One Third and All Ahead Standard. Gives approximately 10 knots.
TWO-MAN CONTROL Term referring to the handling of authenticators for nuclear release message validation. No one man is ever alone with an authenticator. The authenticators are locked in double safes, and no one man has the combination to both.
TYPE 18 PERISCOPE Modem periscope able to act as a means of seeing outside the ship at PD, but also is able to receive radio messages from the satellite and allow reception and analysis of incoming radar signals. Contains video camera and low-light capability as well as a still photograph camera.
T-AVE (AVERAGE REACTOR COOLANT TEMPERATURE) An estimate of in-core water temperature by electrically averaging the outlet high temperature water (T-Hot) and the inlet low temperature water (T-Cold).
T-HOT Hot leg temperature, the temperature of water leaving the reactor core. Usually about 520 to 560 degrees IF.
T-HOT CUTBACK A cutback inserted when T-HOT gets above a trip setpoint.
T.O.T. (TIME-ON-TARGET) A land attack assault in which weapons are launched at carefully planned moments to cause all weapons to detonate on target at the same instant in time.
More remote launching platforms must fire before closer units.
ULTRAQUIET Ship systems lineup done in a tactical situation such as a close trailing OP or in wartime. Only the quietest equipment is running. Offwatch personnel are required to be in bed. The galley, showers, laundry, movies, and maintenance of equipment are all prohibited to minimize noise. Hard-soled shoes are prohibited. Lights are shifted to red to remind the crew of the need for silence.
UNDERHULL An operation in which a submarine sneaks up to a target when the target is in a surface transit or is running shallow. The submarine doing the underhull raises the periscope, starts the video recorder, and drives around the target taking video pictures of the ship’s hull. Especially valuable when done on a new ship, since the pictures are better than if a cameraman were sent into the ship’s drydock. Extremely dangerous operation.
UNIFORM WHISKEY MIKE Code for “your weapon missed me.”
UNIT A torpedo launched by own ship. As opposed to a torpedo (after sonar calls “torpedo in the water”), which is launched by a hostile submarine.
UWT (UNDERWATER TELEPHONE) A sonar system using voice transmissions instead of tones or pulses, used for communication between two submarines that are fairly close.
VACAPES OPAREA Virginia Capes Operation Area. A region off the continental shelf east of Norfolk where submarines of the Norfolk base practice tactics.
VALVE-OP WATER FLASKS (VOWF) Tanks of pure water used for hydraulically operating nuclear system valves. Can also be used to charge to the primary coolant system by air loading with high pressure air.
VARIABLE BALLAST TANKS Tanks used to hold seawater for added weight, or conversely, seawater tanks that can be pumped out or blown out to lighten the ship.
VARIABLE YIELD Yield is a nuclear warhead’s explosive power in kilotons or megatons. A warhead with variable yield can dial in the desired explosive power by changing the shape or size of the implosion charges or by altering the geometry or concentration of the fissionable (or fusion) material.
VECTOR Any quantity that has both magnitude and direction. Example: a velocity vector is speed (number of miles per hour) and direction (north).
VENT To release trapped air from a system.
VERTICAL SURFACE When a hovering submarine blows water from a variable ballast tank to establish a vertical velocity and then rises vertically from the water. Generally only used to surface through the ice.
VICTOR A class of Russian attack submarines built to counter the threat from the Piranha class of submarines.
VICTOR III A class of Russian attack submarines that are much more refined, quieter, and faster than the VICTOR class (only a few VICTOR II’s were built, and may be considered experimental models of the VICTOR Ill’s). Built to counter the Los Angeles class submarines. Precursors to the AKULA class attack submarines.
VITAL BUS A group of electrical loads supplied off the same motor generator breaker, able to be fed either from a turbine generator or the battery. These few loads are vital to the survival of the ship. Examples include primary ship control circuits, slow speed reactor main coolant pumps, reactor protection circuitry, and the wardroom coffee maker.
VLF LOOP An antenna capable of receiving VLF transmissions at depths down to several hundred feet.
VLF (VERY LOW FREQUENCY) Radio transmissions on a longer wavelength than LF but not as long as ELF.
VLS (VERTICAL LAUNCH SYSTEM) New missile launch system on later Los Angeles class attack submarines, in which space in the forward group of ballast tanks has vertical torpedo tubes for launching Javelin cruise missiles. Allows torpedo room space to hold more torpedoes.
WARDROOM (1) Officers’ messroom. Used also as a conference room, briefing room, reconstruction room, junior officers’ office, movie screening room, and place to converse. (2) The group of officers assigned to a ship.
WARSHOT A weapon that is used to sink an enemy ship or inflict damage on a target. As opposed to an exercise shot.
WATCH/WATCHSTATION A watch is an 8-hour shift during which a group of men at specific stations run the submarine. A watchstation is a person’s station or assignment during the watch.
WATCHSECTION A collection of watchstanders who run the submarine for an 8-hour shift called a watch.
WATER SLUG Shooting a torpedo tube when it is only full of water. A “slug” of water is ejected from the tube.
WATERFALL A display of broadband sonar with bearing on the horizontal and time on the vertical. Broadband noise traces fall down the screen, looking like a waterfall.
WIGGLE RANGE TMA range obtained by the wiggling of an advanced sonar system’s towed array hydrophones due to the tow cable moving in the water flowstream. Each hydrophone has accelerometers and instrumentation to determine its position and motion with respect to the contact and own ship.
WIRE GUIDE CONTINUITY A low electrical resistance in the wire guide to a torpedo, indicating the wire is still intact. Loss of wire guide continuity means the weapon got fouled in the wire and cut it, or that the weapon has exploded.
XO (EXECUTIVE OFFICER) Officer who is second in command of a nuclear submarine, responsible to the captain for the administrative functioning of the ship. At battle stations, the XO coordinates the fire-control team and makes recommendations to the captain.
ZIG A term used to describe a target’s maneuver, either a turn, speed change, or both.