Congressmen gathered on Capitol Hill to tout the importance of replacing the nation’s aging ballistic missile equipped Ohio-class submarines.

During a March 4 meeting sponsored by the Submarine Industrial Base Council, Rep. Rob Wittman, R-Va., chairman of the House Armed Services Committee’s subcommittee on readiness, said replacing the boats — also known as SSBNs — will be critical to the nation’s strategic outlook.

“We know how critical [the Ohio-class replacement] … is to our nation’s strategic position in the world and we want to make sure that SSBNs availability match Ohio-class retirement. Or make sure there is no gap in there,” he said.

The United States still “rules the undersea world,” Wittman said, but Congress needs to ensure it continues investing in submarine platforms.

The Navy’s 2016 proposed budget request asked for $1.4 billion toward research and development for the Ohio-class replacement program, also known as the SSBN(X). The program will replace 14 subs.

“Research-and-development efforts will focus on the propulsion plant, common missile compartment development and platform development technologies like the propulsor, strategic weapons system and maneuvering/ship control,” budget documents said.

SSBN-17 will be the first sub to reach the end of its service life in fiscal year 2027, according to a Congressional Research Service report released in February.

“The remaining 13 will reach the ends of their service lives at a rate of roughly one ship per year thereafter, with the 14th reaching the end of its service life in 2040,” the report said.

The Navy would like to have the first replacement procured by fiscal year 2021, the report said.

The need for an Ohio-class replacement — as well as continued procurement of the Virginia-class fast attack submarines — is critical as adversaries bulk up their submarine fleets, said Sen. Richard Blumenthal, D-Conn., who sits on the Senate Armed Services Committee’s subcommittee on seapower.

“The world is more threatening than ever before,” Blumenthal said. “Submarines are a place where [the] competition is endeavoring to overtake us. The Chinese and the Russians both have active submarine programs. … They are investing more heavily than ever before.”

The Navy’s fiscal year 2016 budget includes $3.3 billion in funding for two Virginia-class subs, according to budget materials.

Sen. Christopher Murphy, D-Conn., agreed that China and Russia pose a risk to the United States.

“Russia is not slowing down on its sub-building program,” he said. “We know that they just launched a new class of attack submarines. We know that they are pushing out the envelope of sub patrols ... we know that we’ve seen one within 200 miles of American shores and this is a reality that the United States is going to have to deal with.”

Further, China now has a submarine fleet that is larger than the Navy's. However, the United States still maintains the fastest, stealthiest and most advanced subs in the world, he noted.

Replacing the Ohio-class submarines is important because they represent the sea-based leg of the nation’s nuclear triad, Murphy noted. The United State’s nuclear triad is represented by three legs —  ballistic missile submarines, land-based intercontinental ballistic missiles and heavy bombers.

"There is no future without the sea-based leg of the triad," he said.