'We Thought We Had It Licked'
LPD-17 Woes Vex U.S. Navy, Northrop
By christopher p. cavas
Published: 25 January 2010 Print | Email
A fresh set of problems with the long-troubled LPD 17 San Antonio-class amphibious ships has sidelined two of the vessels, led the U.S. Navy and its largest shipbuilder into a passionate game of finger-pointing, and raised questions about Northrop Grumman's ability to deliver quality work and the Navy's ability to carry out proper shipyard oversight.
LPD 17 Program Concerns: Statements
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The larger issues are coming from two core problems discovered aboard the LPD 17s, five of which are in service with four still to come.
Of more immediate importance is a problem that, left untreated, could wreck the four large diesel engines that drive the ships. The problem is not new but, having once thought a solution was at hand, the Navy and Northrop are once again trying to figure out why a fix hasn't been found.
Another issue, affecting all the ships in the class and other ships built at Northrop's Gulf Coast shipyards, could - unless it's fixed - shorten the service lives of all the ships. But how and why that problem arose could drive closer to the competence of Northrop and the Navy's inspectors to properly inspect weld work.
The Lube Oil Problem
Engineers are trying to figure out how debris - "contaminants" in engineer-speak - is getting into lube oil in the large diesel engines that drive the ships. The contaminants cause excessive wear on bearings that support a crankshaft at the bottom of each engine. If the problem isn't treated, the crankshaft will be thrown out of line and the engine could suffer serious damage or even be wrecked.
The problem isn't new, the Navy said, and showed up about a year ago in the third and fourth ships of the class.
"We thought we had it licked," Jay Stefany, the Navy's program manager for the LPD 17 program, told reporters Jan. 21. "And that's where we were until right before Christmas."
That's when the newest ship in the class, the USS New York (LPD 21), reported a bent crankshaft in one of the four diesel engines that drive the ship. Engineers found that the shaft was thrown out of alignment by scratches being made in the inner ring of the nine bearings that support the shaft - scratches that caused enough of a difference in the thickness of the bearings to make the shaft wobble.
The scratches are caused by particles too small to see - much of them between 20 and 40 microns wide, or about .00118 of an inch, according to Stefany.
Such particles are found in all engines, but there are unofficial reports that the particles causing the latest problems are coming from shipyard work: slag from welding waste and grit from sand blasting.
The problems on the New York showed up in late November, after the ship returned to its base at Norfolk, Va. The ship, commissioned on Nov. 7 during an emotional and highly publicized ceremony at New York City, was widely proclaimed by Northrop as one of the best ships it had ever built, particularly because of its symbolism of the Sept. 11, 2001, terrorist attacks on the World Trade Center - steel from which was used in forging the ship's prow.
Stefany said the problems were a recurrence of similar issues discovered about a year ago on the Mesa Verde (LPD 19) and Green Bay (LPD 20).
"The ships were down for a number of months," he said, and stainless steel shavings were discovered in the lube oil. The problem was not with the Colt-Pielstick PC2.5 STC engines made by Fairbanks Morse Engine, he said, but changes were made in the piping between the engine and a strainer meant to catch contaminants. A new process to flush out the engines was also created and made standard.
The ships subsequently reported no problems. The two earlier ships of the class, San Antonio (LPD 17) and New Orleans (LPD 18), also reported their engines were fine.
More Examinations
But with the new problems on the New York, the ships were examined again. Three of the ships were OK, but the San Antonio found contaminants in three of the four engines. The amphib is now at a shipyard in Norfolk awaiting repairs. The New York is also at Norfolk, where repairs are being made to the crankshaft bearings. Replacement of the bent crankshaft, however, will have to wait for a more extensive shipyard period this spring.
Engineers working for the Naval Sea Systems Command (NAVSEA), Northrop Grumman and Fairbanks Morse are deeply perplexed by the problem, and a design review meeting is to begin Jan. 26 in New Orleans, bringing together all the principals along with the fleet to discover the cause and come up with a permanent solution.
The fleet also is looking into the problem. Early in December, Adm. John Harvey, commander of Fleet Forces Command, ordered Rear Adm. Michelle Howard, commander of Expeditionary Strike Group Two, to begin a Manual of the Judge Advocate General investigation, or JAGMAN, of the problem. The effort reportedly is being led by NAVSEA's Rear Adm. Tom Eccles, the Navy's chief engineer. The investigation is focused primarily on the San Antonio and not the New York, which has yet to transfer to fleet operational control.
The lube oil problem is the latest embarrassment to hit the LPD 17 program, which has suffered a string of well-publicized snags and setbacks almost since the initial construction contract was awarded in 1998. Workmanship problems and bad luck have followed some of the ships even after they entered service - on its long-delayed first deployment in fall 2008, the San Antonio was forced to remain at Bahrain for more than a month to repair weld leaks in the main propulsion lube oil system.
The vexing lube oil problem on the ships is causing nerves to be frayed all around. The engines themselves are slightly modified versions of a tried-and-true model that is in wide use on ships and ashore, and has powered the Navy's LSD 41 Whidbey Island-class amphibious ships since the 1980s. Unsubstantiated charges range from shipyard sloppiness by Northrop Grumman or smaller yards that carry out overhauls to inadequate training of sailors who oversee the operation of the automated engine rooms. There is also the possibility that the fixes identified a year ago simply haven't all been made, said one key engineer.
"Replacing that section of piping from the filter to the intake, that was the main fix," said Lee Graeber, vice president of engineering at Fairbanks Morse and a former NAVSEA engineer. That effort, he said, "is still going on."
And while "dirty lube oil is still the prime suspect for the bearing failures," Graeber feels the bent shaft "was due to engine operation while the bearing on that engine was failing or in the process of failing." Turning off the engine, he said, would avoid such damage.
Contaminants are found in all diesel engines, Graeber said. "They can be created by the combustion process in the engine itself - part of the lube oil filter process is to wash them out. Normally a diesel plant would have several lube oil purifiers that would take these out, and that also is being investigated - whether there are enough purifiers and they are of sufficient size and capacity."
Virtually everything having to do with the engine and the design of the oil lubrication system will be examined at the design review, sources said, including design, welding, construction and maintenance procedures and other equipment.
"They're trying to figure out what's wrong with the damn system," said one exasperated official. "Everybody could raise their hand."
And while the New York is undergoing repairs, work on the San Antonio is on hold pending conclusion of the JAGMAN investigation.
The Weld Problem
A more widespread problem that came to light during the 2008 Bahrain repairs on the San Antonio has to do with substandard welds on pipe joints on ships delivered by Northrop's Gulf Coast yards at Avondale, New Orleans, and Ingalls, Pascagoula, Miss. The thickness of many welds, Stefany said, is too thin, meeting commercial but not military specifications. A design that featured too few hangars that hold pipes in place led to excessive vibration of the pipes on the San Antonio, causing the welds to fail.
The welds would not have failed were there enough hangars, Stefany pointed out. Changes were made to the ship's design and more hangars were added in all the ships. The next ship to be commissioned, the San Diego (LPD 22), will "have the right hangaring from the beginning," he said.
As a result of the problems, all Navy ships under construction at Northrop Grumman were reinspected for weld problems.
"We found a higher-than-expected failure rate on quality of the thickness of the welds," Stefany said. The issue was not that, properly hangared, the welds would soon fail in service. Rather, Stefany said, the welds are "critical for shock survivability and for service life. You need [the thicker weld] dimensions to guarantee that." As a result, he said, a ship designed for a service life of 40 years might only make it to 30.
"It's not as catastrophic [as the lube oil problem] but we're working it," Stefany said. "It's not as in-your-face as the engines are - basically it's just putting more welding material on."
Throughout the summer of 2009, Northrop Grumman and the Supervisor of Shipbuilding (SUPSHIP) at Pascagoula reinspected all welds on all ships. All pipe welders were de-certified and forced to go through retraining, Stefany said. "At the same time we retrained the shipbuilders, we retrained the SUPSHIP guys," he added. Delivery of the destroyer Dewey was delayed so fixes could be made, and Northrop sent a contingent of engineers to California aboard the new assault ship Makin Island to ensure the quality of repair work and carry out repairs if needed.
While pipe weld problems were found on all the Navy ships under construction at Ingalls and Avondale, the Coast Guard's National Security Cutters (NSC) being built at Ingalls apparently evaded the worst of the issue.
"The Coast Guard has not experienced any significant piping issues on its National Security Cutters," spokeswoman Laura Williams said Jan. 22. Some "piping discrepancies" were found and corrected on the second NSC, she said, adding that the first NSC, the Bertholf, "has not experienced any problems, but we are finishing follow up welding inspections to make sure any potential discrepancies are addressed."
The ability of Northrop Grumman and SUPSHIP to properly carry out weld inspections has also come into question because of the pipe weld problem. Reversing a chronic shortage of oversight personnel has been a major pledge of Navy officials over the past three years.
"Last year we saw a marked improvement in the ability of SUPSHIP to hire people," said a Navy official. "But we're going to have issues that come to light. The issues we're talking about go back long before we were able to hire people."
E-mail:
ccavas@defensenews.com.
