Chapter 2—ADMINISTRATION, SUPERVISION, AND TRAININGcan be accomplished by operating at a high frac-tional power.2. The speed of the engines should be gradu-ally increased to the speed specified for the trial.3. The machinery should be operatedeconomically, and designed pressures,temperatures, and number of revolutions must notbe exceeded.4. The full power trial should not be con-ducted in SHALLOW WATER, which is con-ducive to excessive vibration, loss of speed, andoverloading of the propulsion plant.5. A full power trial should continue beyondthe length originally specified, and all observa-tions should be continued until the trial is finished.6. The trial should be continuous and withoutinterruption. If a trial at constant rpm must bediscontinued for any reason, that trial should beconsidered unsatisfactory and a new start made.7. No major changes of the plant set-up orarrangement should be made during economytrials.UNDERWAY REPORT DATA.—Reports oftrials include all the attending circumstances,especially draft forward, draft aft, mean draft,and corresponding displacement of the ship at themiddle of the trial; the condition of the ship’s bot-tom; the last time drydocked; the consumptionof fuel per hour; the average speed of the shipthrough the water; and the average revolutionsof the propelling engines. The methods by whichthe speed was determined should also bedescribed.Reports should also include tabulations ofgage and thermometer readings of the machineryin use, and the revolutions or strokes of pertinentauxiliaries. The auxiliaries in use during the trialshould be stated. Each report should state whetherthe machinery is in a satisfactory condition. If themachinery’s condition is found to be unsatisfac-tory, all defects and deficiencies should be fullydescribed and recommendations made for correct-ing them.TRIAL REQUIREMENTS.—Trial require-ments for each ship cover the rpm for full powerat various displacements and injectiontemperatures. They are furnished to commandersand units concerned, by the Chief of Naval Opera-tions (Operations Readiness Division).As far as reports are concerned, full powertrials are of 4 hours duration. The usual procedureis to operate the ship at full power for a suffi-cient length of time until all readings areconstant, and then start the official 4-hour trialperiod. Economy trials are of 6 hours duration,a different speed being run at each time a trialis made.Once scheduled, trials should be run unlessprevented by such circumstances as:1. Weather conditions which might causedamage to the ship.2. Material troubles which force the ship todiscontinue the trial.3. Any situation where running or completingthe trial would endanger human life.If a trial performance is UNSATISFAC-TORY, the ship concerned will normally berequired to hold a retrial of such character as thetype commander may consider appropriate.The fact that a ship failed to make the requiredrpm for any hour during the trial, and the amountby which it failed, should be noted in the trialreport.OBSERVATION OF TRIALS.—When fullpower trials are scheduled, observing parties areappointed from another ship wheneverpracticable. When a ship is scheduled to conducta trial while proceeding independently betweenports, or under the other conditions where it isconsidered impractical to provide observers fromanother ship, the ship under trial may be directedto appoint the observers.The number of personnel assigned to anobserving party vary according to size and typeof ship. The duties of the observing party areusually as follows:1. The chief observers organize, instruct, andstation the observing party. They check the ship’sdraft, either at the beginning of the trial or beforeleaving port; supervise the performance of theengineroom observers; check the taking of counterreadings; render all decisions in accordance withcurrent directives; and check and sign the trialreports.2-51
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