Underwater Propeller Change,
USS Enterprise, CVN-65

The Boss Nut Breaks

Cutting began the next day in an attempt to reduce the one inch portion remaining at the shaft to a possible one-half inch. Both kerfs No. 1 and No. 2 were trenched out as close as possible to the threads. Divers had become so comfortable with the Kerie cable technique and had such positive control that they were able to cut within a quarter of an inch to the shaft threads.

Two hydraulic jacks were then positioned in kerf No. 1. A pressure of 13,000 PSI (112 tons) finally broke the kerf. Attempts to reposition the jacks and break kerf No. 2 failed. A new type of shim, a 1/2 inch semi cylindrical bar, was attached with countersunk set screws to the face of each ram, and under a pressure of 18,500 PSI, the nut broke.

A grip hoist was rigged to remove the smaller portion of the boss nut. Attempts to pull loose or unscrew the remaining part of the nut only served to bend the eye bolts and part a 5/8 inch wire rope. (See WebMaster Notes below.) It was decided that another cut would be necessary to remove this larger portion of the boss nut. To prepare for cut No. 3, the bent eye bolt was cut off and a hole was burned through near th edge of cut No. 1 to attached a securing line. The other half of the nut was secured with an eye bolt.

Cut No. 3 began along its key way using the 12 MM Kerie cable. Approximately 300 feet of cable was used in about three hours of rough cutting to shape a new trench which was then smoothed out with the 9 and 6 mm cable. Because cut No. 3 was in the8 o'clock position (looking forward), divers had to be on the underwater staging and cutting upward. Many reported they could not see the top of the cut: gases and slag diminished visibility. As a result, kerf No. 3 was extremely rough. In addition to deepening the trench as much as possible at the after face, the kerf was sloped from about 1/2 inch at the after face of the boss nut to do about 1 1/2 inches at the propeller hub. Later, when the jacks were installed and pressure was applied, the cracked could be seen starting at the aft inch of the nut and following along the base of the cut toward the propeller hub. The remaining section of the boss nut broke loose at 2000 PSI.

WebMaster Notes: I was standing watch on the compressor system providing air to the divers this day. When the above-mentioned wire rope broke, it SNAPPED with an unGodly force. A broken piece of cable ricocheted off the underbelly of the flight deck 85 feet above, then hit the deck next to me- missing me by inches. Happened so fast, I didn't have time to be scared until later.

WebMaster Bruce