Groton — Members of Connecticut’s congressional delegation vowed Tuesday to continue to press for funding for the nation’s next-generation ballistic-missile submarines, calling the $80 billion program a linchpin of the nation’s defense.

Sen. Richard Blumenthal and Rep. Joe Courtney, along with Adm. Jonathan Greenert, the chief of naval operations, received updates on the program in a briefing Tuesday at Electric Boat. EB is expected to begin detailed design work for the new sub — which will replace the Navy’s aging Ohio-class boats — in 2017.

“The essence here is this boat will be the strongest, stealthiest, most sustainable of any in the history of the word,” Blumenthal said at a press conference following the closed-door briefing. “And it will be that way for the remainder of the century, without exaggerating.”

The first of the 12 boats would begin patrolling the world’s oceans in 2031, four years after the Navy’s 18 Ohio-class submarines, which carry Trident missiles, begin retiring. Blumenthal and Courtney said the timing was critical.

“There’s really no margin for error here in terms of any delays that might be thrown out there for budget reasons,” said Courtney, D-2nd District. “Obviously, we’ve got to go back and get this done during the lame duck session” that begins after the November mid-term elections.

The House approved the annual defense-authorization bill in May, but the Senate has been slow to take it up. Blumenthal, a Democrat, said Senate leaders were committed to bringing it to a vote before Congress adjourns for the holidays.

Both measures include language for the new submarine class that “absolutely hits the mark … in terms of keeping the project on track,” Courtney said.

Construction of the new ballistic missile boats would begin in 2021. The submarines will take seven years to build, followed by three years of testing, according to EB.

Greenert, the Navy’s senior military officer and member of the Joint Chiefs of Staff, said replacing the Ohio-class submarines “is my Number One program.”

“This is analytically sound, technically sound, good engineering and a deliberate management process to bring the best cost-value that the taxpayers deserve,” Greenert said.