Nimitz Reaches Availability Milestone

Story Number: NNS110707-11Release Date: 7/7/2011 3:27:00 PM
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From Puget Sound Naval Shipyard and Intermediate Maintenance Facility Public Affairs

BREMERTON, Wash. (NNS) -- Puget Sound Naval Shipyard and Intermediate Maintenance Facility (PSNS & IMF) workers announced July 7, they reached a milestone in USS Nimitz's (CVN 68) ongoing maintenance availability with the installation of two new sponsons to the aircraft carrier.

Sponsons are structures that project from the vessel to support a weapon system or antenna array.

The huge assemblies were constructed upside down to accommodate access to the work surfaces, and then two bridge cranes were used in unison to move each of the structures individually outside the building.

"The largest assembly weighed 117,000 pounds," said Wayne Prather, Rigging and Crane Operations division process manager. "Each structure was suspended from a portal crane, and rotated 180 degrees using rigging gear. The larger sponson was rotated first, followed some days later by the second sponson. This placed the sponsons in an upright position. They were then each moved back into the building for some final fitting and welding."

Once welding was complete, the team used two bridge cranes to move the 117,000 pound forward sponson back outside the building and staged it for transport. Next, the team used a portal crane to load the sponson onto the 100-ton capacity shipyard trailer for transport to dry docks and installation on Nimitz.

The forward sponson unit remained suspended from the portal crane for five days until the welding process was complete enough to support the structure. Once the crane was able to disconnect from the first unit, the second sponson was transported and suspended following the same process.

"Because of the length of time that has passed since our team has done work of this nature, the job required substantial planning, engineering, and innovation," David Sell, Lifting and Handling department head. "Not only did we want to refresh our skills for the task, we also wanted to make sure we weren't exposing any workers to unnecessary risks while working with the suspended load."

The four Naval Shipyards - Norfolk Naval Shipyard in Portsmouth, Va.; Pearl Harbor Naval Shipyard and Intermediate Maintenance Facility in Pearl Harbor, Hawaii; Portsmouth Naval Shipyard in Kittery, Maine; and Puget Sound Naval Shipyard and Intermediate Maintenance Facility in Bremerton, Wash., - perform logistic support and work in connection with ship construction, conversion, overhaul, repair, alternation, dry docking, outfitting, manufacturing research, re-development and test work.

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