Navy Secretary Donald Winter came to Bath Iron Works on Tuesday to see shipyard upgrades amid growing questions in Washington over the future of the next-generation Zumwalt-class destroyer, an important project for shipbuilders.

Sen. Susan Collins invited the Navy secretary to get a firsthand look at improvements including its Ultra Hall, which allows shipbuilders to put together larger hull segments in a climate-controlled facility. The facility was built with the Zumwalt in mind.

But the Zumwalt program itself is in question. Contracts have been awarded for construction of only two ships, including one in Bath.

Critics in the U.S. House have threatened to scuttle funding for a third ship, putting it at odds with a spending proposal in the Senate. And Democratic Rep. Gene Taylor of Mississippi has floated a proposal to build more of the current Arleigh Burke destroyers.

Collins, R-Maine, said Tuesday the House proposal doesn’t provide enough funding for either type of destroyer, creating the potential for “a terrible gap in the workload for Bath Iron Works.”

With that political tug-of-war as a backdrop, the Navy appears to be re-evaluating the DDG-1000, which is much larger and more than double the cost of existing destroyers. The Navy brass is considering reconfiguring Arleigh Burke-class destroyers, said defense analyst Loren Thompson.

“They are seriously considering another flight of DDG-51s that would be substantially modified from the existing ships,” said Thompson, from the Washington-based Lexington Institute, a think tank. With some work, the vessels could be modified for missile defense, he added.

The DDG-1000 Zumwalt was originally conceived as a stealth warship with massive firepower to replace the 16-inch guns of retired battleships.

The stealthy warships were designed to bombard the shore with powerful guns from 100 miles away. To get stealth, the Navy opted for a low-profile design featuring an unconventional wave-piercing hull. For stability, and to accommodate the 155mm guns, the ship grew in size. It displaces 14,500 tons, making it 50 percent larger than Arleigh Burke destroyers.

The cost is estimated to be more than double the $1.2 billion price tag of current destroyers. Critics anticipate the costs would grow much higher, making it difficult for the Navy to build large numbers of them while achieving its goal of increasing the fleet to 313 ships.

Winslow Wheeler, an analyst from the Center for Defense Information, said the DDG-1000 has been made largely irrelevant in terms of the conflicts in Iraq and Afghanistan.

“It’s a bad idea run amok,” he said.

Collins disagrees with that assessment.

“The DDG-1000 would give the Navy capability that it does not have now and that it needs. It has more firepower. The crew is only half the size of what’s required for a DDG-51. And it’s also stealthier. That’s something the Navy has wanted for years,” Collins said from Washington.

During his visit to the shipyard, Winter asked BIW President Dugan Shipway about BIW’s capability to build other types of ships.

“My response was short and to the point. I told him we’re ready to build any surface ships he decides the Navy needs,” Shipway said in a statement put out by BIW. Winter’s visit to the shipyard was closed to the media.

Winter last visited Bath Iron Works in January 2006, less than two weeks after he was sworn into office. At the time, he was touring Navy facilities around the country, and he visited Bath Iron Works, Brunswick Naval Air Station and Portsmouth Naval Shipyard all in a day.

Since then, Winter has butted heads with Navy shipbuilders, taking them to task for the high cost of ship construction and for failing to adapt to change.

Bath Iron Works President Dugan Shipway wanted Winter to see that Bath Iron Works is indeed making improvements to become more efficient.

The visit was worthwhile because Winter’s view of American shipbuilding seems to be based mostly on the problems he has encountered with the Gulf Coast yards, Thompson said.

“What he found at Bath was probably the best naval shipbuilding operation in North America in terms of work culture, management and efficiency,” he said. “So it may have been a revelation for him.”