PORTLAND, Maine (AP) -- Bath Iron Works is laying off 179 workers, the largest single job cut in at least three years, officials said Thursday.

The layoffs, effective Jan. 23, reflect workload instability as the Navy's DDG-51 destroyer program winds down and production of the next-generation DDG-1000 destroyer ramps up. Some of the workers could be recalled over the coming year, the company said.

The job cuts cover 11 trades including shipfitters, machinists, pipefitters, welders, electricians and painters, said Jim DeMartini, shipyard spokesman.

The shipyard, which has 5,700 workers, has been reducing its work force because of the long-anticipated workload gap. About 200 jobs were cut last year.

The job losses would be greater if the Navy had not awarded Bath Iron Works the contract to build the lead ship in the DDG-1000 series, DeMartini said. Early fabrication is now under way on the ship, dubbed the Zumwalt, and production will build steam this year.

Two DDG-1000 warships are funded -- the Zumwalt at General Dynamics' Bath Iron Works and a second ship to be built at Northrop Grumman's Ingalls shipyard in Mississippi. The conventional wisdom is that a third ship, which is partially funded, would be built at Bath.

Over the summer, the Navy killed the program after the first three ships are built because the massive destroyers had become too costly.

In the meantime, the Navy has proposed building more of the last-generation destroyers to keep shipbuilders busy and to move the Navy closer to its goal of a 313-ship fleet. Bath would get some of those, but no money has been appropriated.

"There's more than enough demand to keep the entire Bath work force employed, but the Navy's plans on what it needs and when it needs it are so subject to change that workers suffer due to the lack of stability," said Loren Thompson, a defense analyst.

To keep its shipbuilders busy, Bath Iron Works competed to build a Joint High Speed Vessel for the Army, Navy and Marines, and a fast-response Coast Guard cutter. But the shipyard failed to win either of those contracts in the past year.

The murky shipbuilding future could become clearer when President Obama releases his budget request in February. But even then, it will be many more months beyond that before there are definitive answers on future funding, Thompson said.