The leaders of the submarine force typically discuss the importance of building a new class of ballistic-missile submarines privately, but now they are making a more public case.

Nearly all of the senior officers attending a classified conference on undersea warfare technology at the Naval Submarine Base in Groton last week spoke about how critical it is to replace the aging Ohio-class boats, Rear Adm. Barry Bruner said Wednesday.

Bruner, the director of undersea warfare, wrote a blog to coincide with the conference that was aimed at people who don't know a lot about the construction program, or even about the military. In it, Bruner outlined the basic details of the plans because, he said, "We have to have that submarine."

"The audience is really everybody, the American public. If they know anything about the Ohio replacement, they know something they saw in that Gene Hackman movie," he said, referring to "Crimson Tide," the 1995 film that featured a ballistic-missile submarine. "But that's not reality. So I'd like the public to understand what the Ohio replacement does, why it's important."

The educational effort was launched at a time when all of the shipbuilding programs face cuts, given the fiscal environment and the fact that sequestration is looming on the horizon. The $1.2 trillion in automatic spending cuts known as sequestration will take effect Jan. 1 if Congress does not act to prevent it.

The ballistic-missile submarine, which Electric Boat is designing, could be a prime target for budget cutters because of its price tag — the Navy estimates that building the 12 submarines will cost $78 billion. The program was delayed two years, which Bruner said was a financial decision.

"Even without sequestration, the budget is going to continue to come down," he said. "I think what that means is, we have to be evermore deliberate and focused in what we invest in, and in my mind that makes it even more important that we invest in the Ohio replacement."

The two-year delay, Bruner said, "took away any flexibility we might have in the future, so we can't slide it any more to the right."

The sea-based "leg" of the nuclear triad is considered the most able to survive a nuclear attack. Under the new Strategic Arms Reduction Treaty, submarines will carry about 70 percent of the nuclear arsenal instead of 50 percent. Bruner said survivability is the "biggest single thing the Ohio replacement brings to the nation's defense."

"No matter what a potential adversary might do, no matter what kind of surprise they might have, they will not be able to escape the fact we could attack them back if they attack us first," Bruner said.

The Navy has said 12 submarines will serve as a credible deterrent. The current fleet of 14 Ohio-class boats — after operating for 42 years, about a decade longer than their design specifies — will retire one per year starting in 2027.

The force will drop to 10 — at the same time that there are fewer attack submarines in the fleet because those submarines are retiring, too, and while the Navy is trying out the new class of ballistic-missile submarines.

The Navy plans to wait to do the major maintenance work on the ballistic-missile submarines, Bruner said, but that work will need to be done eventually so the number can't stay at 10.

"There's no risk as long as nothing unexpected happens, and certainly we will operate to ensure nothing unexpected does happen," Bruner said.

He said they are continuing to look for ways to control costs without sacrificing the capabilities the submarine would need to be effective until near the end of the century. It will have a reactor core that never needs to be refueled, 16 missile tubes and features that make it stealthier than its predecessor, Bruner said.

"The submarine isn't just another copy of the Ohio," he said. "It is being designed to take us a lot further than the current class could, or would."

j.mcdermott@theday.com