US Navy request raises issue about aluminum ships

* Navy officials say not concerned about Austal ships

* Analysts question Navy move shortly before LCS award

By Andrea Shalal-Esa

WASHINGTON, March 16 (Reuters) - The U.S. Navy is seeking  an analytical tool to predict problems with aluminum-hulled ships just months before it is due to announce the winner of the Littoral Combat Ship competition involving such a ship.

In a little-noticed solicitation posted on a Navy website in January, the Navy said it needed better tools to predict possible cracking on aluminum-hulled ships, especially under difficult conditions at sea. Replies are due by March 24.

The solicitation is one of about 40 research projects aimed at small businesses, and Navy officials say it does not reflect any concern about the aluminum multi-hulled Littoral Combat Ship being built by the U.S. unit of Australia's Austal  in Mobile, Alabama.

The solicitation is one of about 40 research projects aimed at small businesses, and Navy officials say it does not reflect any concern about the aluminum multi-hulled Joint High Speed Vessel or Littoral Combat Ships being built by the U.S. unit of Australia's Austal  in Mobile, Alabama.

"We're confident that the JHSV and the aluminum variant of the LCS will meet all the operational requirements that are out there," said Navy Commander Victor Chen.

"We already have a level of confidence in how to work with aluminum. The Office of Naval Research is trying to expand the knowledge base and build on what we already know," he said.

But congressional sources and defense analyst said the solicitation raised questions about the depth of the Navy's knowledge about the new shipbuilding material just months before it could pick the Austal design for over 55 warships.

Aluminum is often used to build high-speed ferries and similar vessels, but it is a new material for the Navy, which has long relied on steel-hulled ships.

"It's hard to understand how the Navy could consider selecting a design that it says it doesn't understand very well," said defense analyst Loren Thompson of the Virginia-based Lexington Institute.

Austal's three-hulled aluminum warship is competing with Lockheed Martin Corp's  more traditional steel mono-hull ship, for over $5 billion in orders for 10 more additional LCS ships. Bids are due on April 12, and the Navy is expected to pick a single winner by July.

Lockheed and Austal, teamed with General Dynamics Corp , have already delivered one ship of each design to the Navy, and both companies are working on a second ship.

"It's surprising that they would say at this point in the evolution of the program that they don't understand how aluminum might operate under certain difficult conditions," Thompson said.

Lockheed has argued that its steel monohull design would be easier to build and repair at shipyards around the world, which are not as well versed in working with aluminum.

EXTREME LOADING EVENTS

In the solicitation, the Navy said it was facing "great challenges" in picking appropriate analytical tools and validation procedures to assure the performance and integrity of the aluminum ship structure in the presence of "unexpected extreme loading events" such as wave-slamming.

Testing actual structures and then certifying them was costly and would reduce the Navy's ability to achieve an optimal design, it said.

"They're admitting that they don't have a way of rapidly assessing the risks that a specific ship design for an aluminum ship might pose," said one congressional source, who was not authorized to speak on the record.

The Navy's solicitation could factor into possible protests or challenges to an eventual contract award in the competition, which is being closely watched by lawmakers keen to maintain high-paying shipbuilding jobs in their districts.

Lieutenant Commander Chris Servello, a spokesman for the Naval Surface Forces, Pacific, said no specific incident with Independence, the aluminum trimaran LCS built by General Dynamics and Austal, had triggered the Navy posting.

"To date, the testing on LCS-2 hasn't revealed any wave-slamming or any other issues or problems with the make-up of the hull," he said.

Bill Pfister, vice president of external affairs for Austal, also downplayed the importance of the Navy solicitation, saying its emergence was clearly aimed at "clouding" the current heated competition for the LCS design.

He said there had been no incidents of concern regarding the hull structure of Independence, and the Navy had installed sensors several years ago on a similar ship built by Austal, that operates as a ferry in the Canary Islands, to monitor the performance of the aluminum hull.

"We are not concerned about Independence or any other derivative hull form of the ships that we build, Pfister said. "This does not raise any questions about the capability of the Independence aluminum trimaran hull form," he said.

(Reporting by Andrea Shalal-Esa; Editing by Tim Dobbyn)