PORTLAND, Maine — Shipbuilders Bath Iron Works in Maine and Austal USA in Alabama are ending their partnership, allowing each of them to compete on their own for a lucrative contract to build 10 fast and agile warships for the Navy.

Austal will bid as prime contractor against Lockheed Martin Corp. for the first two ships in a contract to be awarded this year that contains options for up to 10 ships with a value of $4.8 billion.

The Navy plans to award another five-ship contract to a different builder in 2012. By breaking up their team, Bath Iron Works will be able to bid on the second contract.

“This gives Austal a chance to continue to compete for the ongoing construction of these ships and it gives us the opportunity downstream to compete with the rest of industry for the remaining ships in the program,” Jim DeMartini, a spokesman for Bath Iron Works, said Friday.

Joe Rella, Austal USA president and chief operating officer, said that working with Bath Iron Works “has enabled us to achieve a level of maturity and experience to be a prime shipbuilder of U.S. naval combatants, and we are ready to take on this new leadership role in the [shipbuilding] program.”

The Navy wants to build a total of 55 littoral combat ships and get them into the fleet as quickly as possible to counter threats including modern-day pirates.

The ships are designed to accommodate helicopters and mission modules for anti-submarine missions, mine removal or traditional surface warfare. The ships can reach about 50 mph to chase down speedboats, and their waterjets and shallow drafts let them zoom close to shore.

There are two competing versions of the ships. With the new contracts, the Navy will settle on one of the designs for the remainder of the production run.

Bath Iron Works, a General Dynamics Corp. subsidiary, teamed with Austal USA, a subsidiary of Australian fast ferry builder Austal, to build a three-hulled ship made of aluminum. Lockheed Martin partnered with a shipyard in Wisconsin to build a ship with a single hull made of steel. Despite their vastly different outward ap-pearances, both ships meet the Navy’s requirements.

Both teams have delivered one ship apiece to the Navy, and both are building a second ship. The Bath-Austal team remains in place until completion of the Coronado, which is under construction in Mobile, Ala.

For Austal and Bath, the breakup after six years comes in response to changes in the way the Navy structured the contracts. The 10-ship contract provided too few warships for Bath to share in construction; ending the partnership gives Bath a shot at the second contract, DeMartini said.

Bath is prepared to bid on the follow-up contract regardless of which design the Navy chooses: the Austal-built version or the Lockheed design, he said.