REMOVAL OF GEARBOX FOR INSPECTION AND MAINTENANCE

CATEGORY I - Vessel in Water

Necessary Components:

A) Tunnel Expansion Plugs (Available Option) or purchase at local plumbing supply.

b) Machined Plate (Available Option) - this plate is machined to match hole layout in saddle and thickness of gearbox flange (1/2").

Procedure:

1.  From inside the vessel, unbolt the two 3/8" hex cap screws that hold the hydraulic motor in place and remove it without disconnecting the hydraulic hoses.

2.  Diver must then remove the stator screens, zinc anodes, nuts, washers and props taking care not to lose the keys in the shaft and prop bore keyways.

3.  Install tunnel expansion plugs in port and starboard ends of tunnel.

4.  Gearbox is then removed from inside the hull by removing the 12 -1/4" hex cap screws and the 2 - 3/8" nuts. Take care not to disturb the 4 saddle mounting bolts and saddle. They are permanent. Gearbox is then lifted out of permanently mounted saddle and special machined plate is fastened down with the screws that held the gearbox in place. The "0" ring is left in its slot in the saddle.

5.  Gearbox can be worked on, and then replaced by reversing the order of removal. Insure that the "0" ring is installed in the saddle "0" ring groove. Use Locktite #242 on the 1/4" hex cap screws and tighten to 10 lb. ft. torque. The two 3/8" nuts should have Locktite #242 applied and tighten to 30 lb. ft. torque.

6.  The prop shaft nuts should have Never Seize applied. The keys should be secured in the shaft with Locktite #242. The props should be installed on the gearbox shafts by a diver. It is essential that the props slide on and off the shafts without great effort. This will ensure that a prop puller will not be required to remove the props for future maintenance.

7.  Slide a wood bar into the tunnel to prevent rotation of the shaft while tightening the prop nuts. The prop nuts are tightened to 50 lb. ft. torque. Finally, screw the zincs on using Locktite #242 and tighten with a plumbers basin wrench. Reinstalling the stator screens  and the hydraulic motor finishes the job.

CATEGORY II - Vessel in Dry-dock

Same as above except diver and expansion plugs and plate are unnecessary.