CARBON  DIOXIDE–A  colorless,  colorless  gas  used  as a fire-extinguishing agent and for inflating life rafts and  life  jackets. CARBON  PACKING–Pressed  segments  of  graphite used  to  prevent  steam  leakage  around  shafts. CASUALTY POWER SYSTEM–Portable cables that are rigged to transmit power to vital equipment in an  emergency. CENTRAL  CONTROL  STATION  (CCS)–The  CCS is the main operating station from which a majority of   the   engineering   plant   machinery   can   be controlled and monitored on modern naval ships. CHECK VALVE–A valve that permits the flow of a liquid in one direction only. CIRCUIT   BREAKER–An   electrical   device   that provides  circuit  overload  protection. CLUTCH–A form of coupling designed to connect or disconnect a driving or driven member. COLD  IRON–The  condition  of  an  idle  engineering plant when all port services are received from an external source such as shore or tender. CONDENSATE–Water   produced   in   the   cooling system, of the steam cycle, from steam that has returned  from  the  turbine  or  from  steam  that  has returned  from  various  heat  exchangers. CONDENSER–A  heat-transfer  device  in  which  steam or vapor is condensed to water. CONDUCTION–A method of heat transfer from one body to another when the two bodies are in physical contact. CONSTANT   PRESSURE   GOVERNOR–A   device that  maintains  a  constant  pump  discharge  pressure under  varying  loads. C O N T R O L L A B L E     R E V E R S I B L E - P I T CH PROPELLER  (CRPP)–A  propeller  whose  blade pitch can be varied to control the amount of thrust in both ahead and astern directions. CONTROLLER–A  device  used  to  stop,  start,  and protect motors from overloads while the motors are running. COOLER–Any  device  that  removes  heat. CORROSION–The  process  of  being  eaten  away gradually by chemical action, such as rusting. COUNTERSINK–A  cone-shaped  tool  used  to  enlarge and bevel one end of a drilled hole. CREEP-RESISTANT  ALLOY–A  metal  that  resists the slow plastic deformation that occurs at high temperatures when the material is under constant stress. CROSS-CONNECTED   PLANT–A   method   of operating two or more systems as one unit. CURTIS   STAGE–A   velocity-compounded   impulse turbine stage that has one pressure drop in the nozzles and two velocity drops in the blading. DEAERATING  FEED  TANK  (DFT  or  DA  tank)–A device  used  in  the  waste-heat  boiler  system  to remove  dissolved  oxygen  and  noncondensable gases from the feedwater. DEBALLASTING–The process by which seawater is emptied  from  tanks  to  protect  the  ship  from underwater  damage  and  to  increase  its  stabilitySee BALLASTING. DEGREE  OF  SUPERHEAT–The  amount  by  which the temperature of steam exceeds the saturation temperature. DIESEL FUEL MARINE–A fuel oil. DIRECT CURRENT (dc)–current that moves in one direction  only. DIRECT DRIVE–One in which the drive mechanism is coupled directly to the driven member. DISTILLATE–Water  produced  in  distilling  plants. DISTILLING   PLANT–A   system   that   converts seawater  into  fresh  water  commonly  called evaporators  (evaps). DRAWING–An illustrated plan that shows fabrication and  assembly  details. DRUM, STEAM–The large tank at the top of the boiler in which the steam collects. DRUM, WATER–A tank at the bottom of a boiler. DUCTILITY–The property possessed by metals that allows them to be drawn or stretched. ECONOMIZER–A  heat-transfer  device  on  a  boiler that uses the gases of combustion to preheat the feedwater. EDUCTOR–A  jet  pump  that  uses  water  to  empty flooded  spaces. EFFICIENCY–The ratio of the output to the input. ELASTICITY–The ability of a material to return to its original  size  and  shape. AI-2