Sub’s commissioning delayed by bad bolts

[CommunityEditor]

Commissioning ceremonies for the new nuclear-powered attack submarine New Mexico have been delayed until next year while Northrop Grumman shipbuilders work to fix construction problems in the vessel’s torpedo room, the U.S. Navy said Thursday.

Capt. Michael Jabaley, the Navy’s Virginia-class submarine program manager, said Northrop Grumman’s Newport News, Va., shipyard and the Naval Sea Systems Command continue to investigate the problem, which so far has been found on four submarines. One of the submarines, the North Carolina, already is in service, but is undergoing a shipyard period at the General Dynamics Electric Boat shipyard in Groton, Conn. Two other submarines with the problem, the Missouri and California, are in various stages of construction.

Another in-service submarine, the New Hampshire, apparently escaped the problem.

“The most immediate concern based on schedule was the New Mexico,” Jabaley said. The ship is about 99 percent complete, he said, and had been scheduled to be delivered to the Navy on Sept. 30. The commissioning ceremony had been scheduled for Nov. 21 at Norfolk, Va.

But Northrop Grumman and the Navy estimate about five weeks of work will be required to fix the problems on the New Mexico, and the new target delivery date of Nov. 13 didn’t provide enough margin to ensure the ship would be ready by the 21st.

“We thought it would be prudent to delay the ceremony,” Jabaley said. “Typically, we like two to three months between delivery and commissioning to give the crew time to become proficient at operating at sea.”

The holiday period beginning with Thanksgiving was also a factor in the delay, Jabaley said. A new date hasn’t yet been set, but it will “probably be in January or February,” he said.

Even so, Newport News still has a shot to beat the contract delivery date of April 30, 2010. Beating the delivery date has become an important factor in keeping down costs, and Electric Boat, which shares equally with Newport News in building the submarines and alternates with the Virginia yard in completing the ships, has delivered its last two submarines ahead of schedule.

The New Mexico is the third Virginia-class submarine to be completed at Newport News, and the company hopes it’s the first one delivered ahead of schedule.

“Northrop Grumman understands and supports the U.S. Navy's decision to delay the commissioning ceremony for the New Mexico until early 2010, to allow for completion of construction and repair work,” said company spokeswoman Margaret Mitchell-Jones. “We take the quality of our work and product quality very seriously and we have instituted improvements in our engineering, production and quality systems across Northrop Grumman Shipbuilding. We are focused on completing the construction of New Mexico, and we look forward to delivering a great ship to the Navy.”

The bolt problem came to light in early August when Electric Boat workers had trouble ensuring a proper fit in the tracks of the weapon handling system aboard the submarine Missouri. Newport News builds the weapons room section of all Virginia-class submarines, and GD, as prime contractor on the Virginia-class program, reported the problem to the Navy on Aug. 6.

‘No Safety Issues’
Jabaley took pains to say there were no safety issues with the bolt problem.

“This would cause a problem in operation only in the most strenuous situations — high forces due to shock, such as when a mine or torpedo detonates near you. For normal operations it’s not a concern at all,” he said.

The bolts, or “fasteners” in engineering parlance, hold together sections of track in the large weapons room of the submarines. The Virginia-class submarines employ a unique system to handle their weapons, which are placed in trays or cradles to be moved around the room and guided by the tracks.

Some of the tracks didn’t line up properly, and EB engineers traced the problem to the bolts. The Navy, in a written statement issued Aug. 19, said, “shipbuilders have found improperly drilled and machined bolt holes, bolts that had been improperly machined, and fasteners that were not installed and tightened properly.”

Such a problem, the Navy statement said, “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.”

Jabaley noted that about 340 bolts or fasteners were initially being inspected in each submarine’s weapons room.

“We’ve now expanded the inspections to similar applications, to ‘close-tolerance, bolted fit-up.’ That’s where you’re bolting two things together that require a very finely-machined bolt goes through a very finely-machined bolt hole,” Jabaley said. “We’ve ended up with a total of a little over 900 fasteners ship-wide.”

While the New Mexico’s delivery will be delayed, the work to fix the other submarines is not expected to delay their completion.

“On other ships that can be done in parallel with other work,” Jabaley said.

The New Mexico’s crew officially moved aboard July 28 and will not be required to leave the ship during the repairs, Jabaley said, noting that much of the crew still lives ashore. “The duty section spends the night aboard when they’re on duty,” he noted. “The repairs required are primarily in the torpedo room. It’s not an impact to habitability, and the galley is still fully operational.”

Northrop Grumman and the Navy continue to investigate the extent of the problem, Jabaley said, and are inspecting the other four Virginia-class submarines already in service.

“This is a process we expect to take a couple more weeks [before we] understand the impact on the ships we’ve delivered,” he said.


Article: http://www.navytimes.com/news/2009/0...exico_090309w/