The nation’s shipyards and their supply chains could build three Virginia-class nuclear attack submarines annually but to create the necessary capacity will require the government to commit to such a plan, the head of shipbuilder Huntington Ingalls Industries [HII] said on Thursday.

“Our supply chain in support of all of shipbuilding but in particular our nuclear enterprise, it’s very capable but it’s also kind of thin and so you really need to have a persistent, consistent, sustainable set of messaging to the industry that you’re going to sustain this rate for a significant time to create or track the investment in technology, capital and people that supply chain’s going to need to go do,” Mike Petters, HII’s president and CEO, said during the company’s third quarter earnings call. “I think the shipyards are ahead of that,” he added, referring to HII’s Newport News Shipbuilding division and General Dynamics’ [GD] Electric Boat shipyard.

The two companies have been working together on this issue “and we’re all working it with the Navy and so I think there is the capacity to go do that but it ain’t a light switch and you don’t turn it on overnight,” he said. “My rule of thumb though is if you’re persistent on these signals from the government, the capacity in the industry can be built faster than the government can appropriate the funding to go do it.”

These signals include long-lead time purchases, requests for proposal and other messages “that would let the industry know that you’re really serious about doing it,” Petters said. He added that “I’m pretty optimistic about it,” noting that the Defense Department will always want more submarines.

HII and GD jointly produce the Virginia-class subs, which typically are built at two per year. Defense Secretary Mark Esper in early October outlined plans for a future Navy fleet that includes more attack submarines, saying three Virginia vessels need to be built annually as soon as possible.

GD Chairman and CEO Phebe Novakovic in October said that if the Defense Department moves forward with a plan for three Virginia-class subs a year her company can “accommodate it.”

Petters said that if the U.S. government decides it wants to acquire three Virginia subs annually, industry will have to invest in more capacity and workforce and that this might include the creation of “some parallel capacity” for things like “structural units or fittings or foundations” that currently are built by his company.