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发表于 2011-3-20 12:34
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来自： 中国江苏南通
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http://www.bloomberg.com/news/20 ... acks-navy-says.html
Lockheed Martin’s First Littoral Combat Ship Develops Cracks, Navy Says
By Tony Capaccio - Mar 18, 2011 12:30 PM GMT+0800
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Lockheed Martin Corp. (LMT)’s first new warship for operating close to shore developed a crack as long as six inches through its hull during sea trials, prompting a U.S. Navy investigation of the design.
The Navy is analyzing the crack to determine if changes are required for future Lockheed Martin hulls, Naval Sea Systems Command spokesman Christopher Johnson said yesterday in an e- mail. This includes reviewing “the design, construction drawings and welding procedures,” he said.
During a heavy-weather ocean trial on the USS Freedom in mid-February, he said, sailors discovered a six-inch horizontal hull crack below the waterline that leaked five gallons an hour. Inside the hull the crack measured three inches. It originated in a weld seam between two steel plates.
The ship returned to its home port in San Diego, avoiding rough seas, after the commanding officer judged the leak rate “manageable,” Johnson said.
Smaller cracks that indicated welding “defects” showed up in the welds of the vessel’s aluminum structure during sea trials last year, Johnson said in his e-mail.
Initial analysis of the second Lockheed-built vessel, the USS Independence, showed improved welding, he said.
A spokesman for Lockheed Martin, Keith Little, said the company “is working closely with the Navy to confirm the root cause” and has made all necessary repairs to the ship. “We are also supporting the Navy in additional testing along the hull to confirm this crack was an isolated anomaly,” Little said.
First of 55
The USS Freedom is the first of 55 Littoral Combat Ships planned. The Navy accepted the $645 million vessel in September 2008; its maiden voyages included drug seizures in the southern Caribbean and sea trials.
Steve Taylor, a spokesman for U.S. Representative Todd Akin, a Missouri Republican who is chairman of the House Armed Services seapower panel, said the Navy had not told the lawmaker or staff about the cracks issue. The problem was not disclosed by Navy officials during a March 9 subcommittee hearing on shipbuilding.
“Congressman Akin is very interested in any indication there are cracks or cracking,” Taylor said. “It is of interest to the committee.”
“This presents a new potential oversight issue for Congress,” said Ronald O’Rourke, naval analyst for the nonpartisan Congressional Research Service.
Johnson said in his e-mail that repair of the hull crack was completed March 12.
In 2005, the estimated cost of the Freedom was put at $215 million, according to CRS. Since then, cost estimates for the first two vessels have more than doubled.
Fatigue Analysis
Johnson said that several years ago the Navy conducted an “early fatigue analysis” on the Freedom that “identified high-stress areas” in the aluminum superstructure. The areas were fitted with instruments to collect data and to monitor for cracks.
Cracks showed up late last year in the predicted areas. The measuring instruments remain in place, and the Navy implemented some design changes to the superstructure “to correct high stress and fatigue issues,” Johnson said.
Lockheed, based in Bethesda, Maryland, and Marinette Marine Corp. of Marinette, Wisconsin, are working together on one model. It is based on a steel monohull and aluminum superstructure.
The other design is an all-aluminum trimaran being developed by the Mobile, Alabama-based U.S. subsidiary of Australia’s Austal Ltd. (ASB) and General Dynamics Corp. (GD) General Dynamics is providing combat systems designed at its Pittsfield, Massachusetts, facility for the Austal vessel.
Close-In Missions
Littoral Combat Ships are designed to operate closer to coastlines than existing surface vessels, such as destroyers, for missions such as clearing mines, hunting submarines and providing humanitarian relief.
The Navy on Dec. 29 awarded contracts for the construction of as many as 10 Littoral Combat Ships to each team.
The Lockheed Martin team received a $491 million contract that could be worth as much as $4 billion when all options are exercised. Austal won a $465 million contract that could reach as much $3.78 billion if all options are exercised.
Contracts for a second vessel each were awarded yesterday. Lockheed Martin received a $376 million job and Austal a $368 million contract.
To contact the reporter on this story: Tony Capaccio in Washington at acapaccio@bloomberg.net
To contact the editor responsible for this story: Mark Silva at msilva34@bloomberg.net |
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发表于 2011-3-20 12:29
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