12/31/2009
NEWS BRIEFS
Bolts Fixed, Northrup Grumman Delivers $2.3b Navy Submarine
Courtesy Northrop Grumman
Northrop Grumman Corp. delivered the submarine New Mexico to the U.S. Navy, months after fastener problems delayed the project.
“Workers at the company’s Newport News shipyard pressed to finish the sub by the end of the year after finding construction errors in the boat’s weapons room that delayed its scheduled August delivery and November commissioning,” reports Peter Frost in the Daily Press of Hampton Roads, VA.
The Navy has scheduled the commissioning for early 2010.
Improperly installed bolts on weapons-handling systems had delayed delivery of the New Mexico – one of four U.S. Navy Virginia-class submarines to be sidelined by the bolt issue. The others include the North Carolina, Missouri and California.
Workers at Northrop Grumman’s Newport News shipyard reportedly mishandled the fasteners that hold together tracks on which weapons are moved in the sub’s torpedo room.
“During the final alignment of the forward and aft weapon cradle tracks aboard the Missouri, several bolts, bolt holes and fasteners were found that did not meet specifications. Specifically, the shipbuilders have found improperly drilled and machined bolt holes, bolts that had been improperly machined, and fasteners that were not installed and tightened properly,” according to a written statement from Naval Sea Systems Command (NAVSEA).
The application of nonspecification bolts, bolt holes and fasteners “could result in a misalignment of the weapons-handling equipment that could prevent the movement of weapon cradles within the torpedo room, and could compromise the integrity of the weapons handling system in a shock event,” according to a NAVSEA statement quoted in the Navy Times.
Inappropriate use of the fastener adhesive Loctite was also reportedly part of the issue.
Northrop Grumman described the problem as including “use of the incorrect grade of Loctite; close tolerance bolts that were modified without the proper use of appropriate technical direction (certain shanks tapered, thread ends cut short); close tolerance bolts that did not meet the diametrical clearance requirements for the respective hole; truss tapped holes that were damaged and nonconforming threads.” ©2009 GlobalFastenerNews.com
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