ENGINEMAN  1  &  C 2. The assistant chief observers assist the chief observers  as  directed;  supervise  the  performance of  the  observers;  check  the  taking  of  fuel  oil soundings  and  meter  readings;  and  make  out  the trial reports. 3. Assistant observers take fuel soundings, meter readings, counter readings, the ship’s draft, and collect all other data that may be required for the trial reports. The  following  items  should  be  accomplished or considered before starting the trial: 1. When requested by the observing party, the ship  under  trial  should  provide  or  designate  a suitable  signaling  system  so  that  fuel  soundings and the readings of counters and meters may be taken   simultaneously. 2.  The  ship  under  trial  should  furnish  the chief observer with a written statement of the date of  last  undocking,  and  the  authorized  and  actual settings of all main machinery safety devices and dates when last tested. 3. The ship should have its draft, trim, and loading conform to trial requirements. In case a least  draft  is  not  specified,  the  liquid  loading should equal at least 75% of the full load capacity. 4.  The  chief  observer  should  determine  draft and  trim  before  and  after  the  trial,  verify  the amount of fuel on board and correct this amount of  the  time  of  beginning  the  trial.  The  draft observer should also determine the rpm required for the full power trial, at the displacement and injection temperature existing at the start of the trial. 5.  The  observing  party  should  detect  and promptly correct any errors in recording data, since it is important that the required data be cor- rect within the limits of accuracy of the shipboard instruments. 6. The chief observer should instruct members of the observing party to detect any violation of trial  instructions,  of  instructions  in  the  Naval Ships’ Technical Manual, or of good engineering practice, and then verify any such report and pro- vide the commanding officer or a detailed account of each violation. MANNER OF CONDUCTING TRIALS.— Some  of  the  requirements  in  regards  to  the manner of conducting full power and economy trials are as follows: 1. Unless otherwise ordered, a full power trial may be started at any time on the date set. 2.  The  trial  should  be  divided  into  hourly intervals,   but   readings   should   be   taken   and recorded every half hour. Data are submitted as hourly readings in the trial report. 3.  Fuel  expenditures  for  each  hourly  interval of the trial should be determined by the most ac- curate  means  practicable,  normally  by  meter readings corrected for meter error and verified by soundings. 4. The appropriate material condition of the ship should be set during the different trials. 5.  During  all  trials  the  usual  “housekeeping” and auxiliary loads should be maintained and the minimum  services  provided  should  include  nor- mal  operation  of  the  distilling  plant,  air  com- pressor,  laundry,  galley,  ventilation  systems, elevators (if installed), and generators for light and power  under  load  conditions  similar  to  those  re- quired for normal operations at similar speeds under the prescribed material condition. 6.  All  ships  fitted  with  indicators,  torsion- meters, and other devices for measuring shaft or indicated horsepower should make at least two observations  during  the  full  power  trial  to  deter- mine the power being developed. 7.  The  chief  observer’s  report  of  the  trial should state whether all rules for the trial have been  complied  with. SOME  HINTS  IN  REGARD  TO  FULL POWER   TRIALS.—There   are   special   forms used for full power and economy trial reports. Illustrations of these forms are not given in this training  manual,  but  you  can  obtain  copies  from your log room, and in this way get an idea of the data and readings that are required for full power and economy trials. Trial forms, and such items as tachometers, stop watches, and flashlights, should be available to  the  observing  party  and  to  the  personnel  who take readings. Any gages or thermometers which are considered doubtful or defective should be replaced before trials are held. A quartermaster must check and adjust all clocks in the engineer- ing spaces and on the bridge before any trials are held. 2-52