During a naval shipyard overhaul, the following work should be performed: inspection of the condition and clearance of thrust shoes to ensure proper position of gear; inspection of the thrust collar, nut, and locking device; and inspection of the flexible couplings between turbines and reduction gears and removal of the sludge deposits.

FULL POWER TRIALS

The correction of any defect disclosed by regular tests and inspections, and the conscientious observance of the manufacturers instructions, should assure that the gears are ready for full power at all times.

It is not advisable to open up gear cases, bearings, and thrusts immediately BEFORE TRIALS. In addition to the inspections which may be directed by proper authority which are conducted during the FULL POWER TRIALS, the following checks must be made AFTER TRIALS. Open the inspection plates, and examine the tooth contact and the condition of the teeth to note changes that may have occurred during the trials. (Running for a few hours at high power will show any possible condition of improper con-tact or abnormal wear that would not have shown up in months of operation at lower powers.) Check the clearance of the main thrust bearing.

SAFETY PRECAUTIONS

Observe the following safety precautions which apply to the operation, care, and maintenance of reduction gears and related equipment found on Navy ships.

1. If churning or emulsification of the oil in the gear case occurs, the gear must be slowed down or stopped until the defect is remedied.

2. If the supply of lubricating oil to the gears fails, the gears should be stopped and the cause located and remedied.

3. When bearings have been overheated, the gears should NOT be operatedexcept in extreme emergenciesuntil bearings have been examined and defects have been remedied.

4. If excessive flaking of metal from the gear teeth occurs, the gears should not be adjusted, except in case of emergency, until the cause has been determined.

5. Unusual noises should be investigated at once, and the gears should be operated cautiously or stopped until the cause for the noise has been discovered and remedied.

6. No inspection plate, connection, fitting, or cover which permits access to the gear casing should be removed without specific authority of the engineer officer.

7. The immediate vicinity of an inspection plate joint should be kept free from paint and dirt.

8. When gear cases are open, precautions should be taken to prevent the entry of foreign matter. The openings should never be left unattended unless satisfactory temporary closures have been installed.

9. Lifting devices should be inspected carefully before being used and should not be overloaded.

10. Naked lights should be kept away from vents while gears are in use (the oil vapor may be explosive).

11. Ships anchored in localities where there are strong currents or tides should take precautions and lock the main shafts.

12. When divers are in the vicinity of the propeller, propeller shafts should be locked.

13. When a shaft is allowed to turn or trail, the lubrication system must be in operation.

14. The main propeller shaft must be brought to a dead stop position before an attempt is made to engage or disengage the turning gear.

15. When a main shaft is being locked, precautions must be taken to apply the brake quickly and securely.

16. Where there is a limiting maximum safe speed at which a ship can steam with a locked propeller shaft, this speed should not be exceeded.

17. When the main gears are being jacked over, precautions must be taken to see that the turning gear is properly lubricated.

18. Before the main engines are started, it should be definitely determined that the turning gear has been disengaged.