Underwater Propeller Change,
USS Enterprise, CVN-65

Special Equipment Requirements

As planning got underway it became necessary to make provisions for the special equipment required to change such a large propeller underwater. Through innovative use and/or modification of existing equipment the Navy diving community extended its capabilities to a new limit and demonstrated its ability to accomplish a broad range of underwater tasks. The use of special underwater equipment and techniques was a key factor in the successful completion of the Enterprise propeller change.

Initial planning for unseating the propeller hub from the propeller shaft taper called for a specially modified strongback, six hydraulic pancake jacks and a special steel collar. During the propeller change, the six hydraulic jacks were coupled together and mounted to the strongback pressure plate. Their total force of 660 tons was expected to unseat the propeller. These jacks were also used earlier in the operation to break the propeller boss nut.

The strongback on which the jacks were mounted had been additionally reinforced and modified for this operation by the crew of the Hector. The pressure plates on which the jacks were mounted were 1-1/2" thick steel plates. A special steel collar was designed and fabricated to protect the shaft end cap and permit the force of the six hydraulic jacks to be applied directly against the shaft shoulder. The three 50-ton chain hoists were specially procured to handle the 34-ton propeller. These hoists operated on compressed air which was supplied by a dedicated, mobile air compressor located on the pier. The hoists were specially modified and tested for operation underwater. Modifications to each hoist included removing the air exhaust muffler and installing an air exhaust hose to prevent seawater from entering the hoist motors. A low pressure air line was installed in the midsection brake housing to keep the brake linings free of saltwater as well.

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