the ship. Without adequate and proper means of communication between the different units, the whole organization of casualty control will fail in its primary objective. To  ensure  that  sufficient  means  of  com- munications  are  available,  several  different systems  are  installed  aboard  ship.  The  normal means of communications are the battle telephone circuits   (sound   powered),   interstation   2-way systems (intercoms), ship service telephones, ship’s loud speaker (1-MC), and voice tubes. Messengers are  also  used  in  some  situations  when  other methods  of  communications  are  not  available  or when written reports are required. The transmission of correct information re- garding  a  casualty  and  the  speed  with  which  the report is made are essential to be of value in any method of communication. It  is  also  essential  that  control  of  all  com- munication circuits be established by the con- trolling station. The circuits must never be allowed to  get  out  of  control,  because  of  “cross-talk” caused by more than one station operating at the same time and each assuming that it has the prior- ity  message.  Casualty  control  communication must  be  incorporated  into  casualty  control  train- ing, since prompt action to notify the control sta- tion or engineering control of a casualty must be taken  to  prevent  the  development  of  other casualties which could be more serious than the original   casualty. INSPECTION  AND  MAINTENANCE Inspection and maintenance are vital to suc- cessful  casualty  control,  since  they  minimize  the occurrence of casualties due to material failures. Continuous and detailed inspections are necessary not  only  to  discover  partly  damaged  parts  which may fail at a critical time, but also to eliminate any underlying conditions which may lead to early failure (maladjustment, improper lubrication, cor- rosion, erosion, and other causes of machinery damage).  Particular  and  continuous  attention must  be  paid  to  symptoms  of  malfunctioning, such  as  unusual  noises,  vibrations,  abnormal temperatures,  abnormal  pressures,  and  abnormal operating   speeds. Operating   personnel   should   thoroughly familiarize   themselves   with   the   specific temperatures,  pressures,  and  operating  speeds required  for  the  normal  operation  of  equipment, in  order  to  detect  all  departures  from  normal operation. When a gage, or other instrument recording the operating conditions of machinery, gives an abnormal  reading,  the  cause  must  be  fully  in- vestigated. A spare instrument, or a calibration test, will quickly indicate whether or not the ab- normal reading is due to instrument error. Any other cause must be traced to its source. Because of the safety factor commonly incor- porated in pumps and similar equipment, con- siderable loss of capacity can occur before any external evidence is readily apparent. Changes in the operating speeds (from those normal for the existing  load)  of  pressure-governor-controlled equipment  should  be  viewed  with  suspicion. Variations from normal pressures, lubricating oil temperatures,  and  system  pressures  indicate  either inefficient   operation   or   poor   condition   of machinery. When a material failure occurs in any unit, a prompt inspection should be made of all similar units to determine if there is danger that other similar failures might occur. Prompt inspection will prevent a series of repeated casualties. Strict  attention  must  be  paid  to  the  proper lubrication  of  all  equipment.  Frequent  inspections and samplings must be made to ensure that the correct quantity of the proper lubricant is in the unit. Lube oil samples must be taken daily on all operating auxiliaries. Lube oil samples should be allowed to stand long enough for any water to settle. Where auxiliaries have been idle for several hours,  particularly  overnight,  a  sufficient  sample should be drained from the lowest part of the oil sump to remove all settled water. Replenishment with fresh oil to the normal level should be in- cluded in this routine. The presence of saltwater in the oil can be detected by running a standard chloride test. A sample of sufficient size for test purposes can be obtained by adding distilled water to the oil sam- ple, shaking vigorously, and then allowing the water to settle before draining off the test sam- ple. Because of its corrosive effects, saltwater in the lubricating oil is far more dangerous to a unit than an equal quantity of freshwater. Saltwater in  units  containing  oil-lubricated  ball  bearings  is particularly harmful. ENGINEMAN  1  &  C 9-2