Underwater Propeller Change,
USS Enterprise, CVN-65

Dunce Cap Removal

The Enterprise was moored in 50 feet of water. 85 feet away from Pier 3 at the Naval Air Station Alameda, California. A large floating barge was positioned on the starboard side of the carrier near the stern, between the pier and the carrier. The barge was equipped with a HUGE steel "balance beam" actually welded to the floor of the barge. One of the 50-ton chain hoists was suspended from the end of the Balance Beam protruding over the side of the barge. Two hydraulic power units, a counterbalance weight, divers' control station, divers' mobile air compressor units, and all related diving equipment were then loaded on the barge.

With the barge and equipment in position, the dive team was ready to begin the propeller change. The first step was to remove all but four screws from the dunce cap and gland seal. The remaining section of rope guard (all but two retaining nuts), the lifting eye plug and the fill-drain plugs were then removed.

The lifting eye was installed in the dunce cap and the two remaining retaining nuts were removed. Two 10-ton chain hoists were then attached to the Enterprise propeller lifting shell fittings and rigged to the dunce cap. The aft chain hoist was used to pull the dunce cap off the propeller hub. The dunce cap was then brought alongside the barge in a yard-and-stay arrangement using a grip hoist and snatch blck attached on the barge deck.

After the dunce cap was removed to pierside, the forward chain hoist was temporarily moved to the aft propeller lifting shell fitting so as not to intefere with the jacking of the screw. The screw was jacked over, and the retaining bolts were removed from the forward retaining ring.

WebMaster Bruce