Groton — The Navy is entering one of the most complex submarine-building eras since the 1970s, the admiral in charge of the service's undersea warfare division said Friday at the U.S. Submarine Veterans Groton Base.

Rear Adm. Bill Merz, essentially the chief financial officer for the submarine force, a job which means he has oversight over a roughly $21 billion budget, gave a taste of his day-to-day thinking as part of the Nautilus Chapter of the Naval Submarine League's luncheon speaker series.

The short version, he said, is growing adversaries and shrinking resources.

Merz reiterated a sports analogy used by Adm. John Richardson, chief of naval operations, to describe the competition the U.S. Navy faces: "He says that since the '90s we've been in a very long off season. We're slower. We're gaining weight. We're not as sharp as we used to be, and we need to fix that."

Competition and the threat posed by our adversaries is what keeps Merz and other Navy brass up at night, he said.

But staying ahead of our adversaries does not all reside in building a better submarine, Merz said. "A lot of it is just our mentality on how we operate these submarines."

He also would like to see the submarine-design process speed up.

"We cannot take 20 years to do this," he said. "In the timeframe of 20 years, some of our more higher-end adversaries are already designing and fielding two to three different classes of submarines. So we're going to lose that war."

The Navy, Merz said, already is thinking about the capabilities it wants the next generation of Virginia-class attack submarines to have, even though the first of those boats isn't expected to be purchased until 2034. The Navy soon will be sending out a confidential letter to the defense industrial base with recommendations on some of the capabilities it would like to see implemented, he said.

"Right now we shoot Tomahawks and we shoot torpedoes, so if the threat doesn't fall into that window, we have to pass it off to somebody else. We think we can do a lot better than that," Merz said, indicating one possible area for improvement.

Merz's talk came a day after acting Navy Acquisition Chief Allison Stiller and acting Navy Secretary Sean Stackley delivered testimony to two separate congressional committees about the Navy's plan to build an additional attack submarine in fiscal year 2021. Originally only one attack submarine was going to be built that year. Stiller, in her testimony, also mentioned the possibility of building three attack submarines in fiscal year 2022 and fiscal year 2023.

That was the first public discussion by the Navy in Congress about taking the production of attack submarines to three per year, U.S. Rep. Joe Courtney, D-2nd District, said in a phone interview Friday morning. "It's no longer just talking in the back halls."

From a money perspective, that's going to be a "huge" challenge, Merz said. But, he added, "If the nation wants these submarines, the money will come."

"It's the stress of workforce that is always the question, whether they have capacity to build the submarines," Merz said. Though he said the Navy has "very high confidence" in Electric Boat — company President Jeff Geiger was present at Friday's luncheon — and Newport News Shipbuilding in Virginia, which together build the Virginia attack submarines under a teaming agreement.

Geiger has said that EB is poised to meet the Navy's demand, provided it has the time to build up its workforce, supplier base and facilities.

j.bergman@theday.com