The attack submarine USS Boise (SSN 764) departs after a scheduled port visit in Duqm, Oman, Aug. 18, 2014. (Photo couresty U.S. Navy photo by Mass Communication Specialist 2nd Class Daniel M. Young).

The state’s two U.S. senators are urging the Navy to speed up the overhaul of a sidelined attack submarine to “ensure that as many boats as possible populate the fleet.”

The USS Boise, a Los Angeles-class attack submarine based in Norfolk, Va., has lost its dive certification – meaning it can no longer submerge – due to a large maintenance backlog at the public shipyards. The submarine has been sitting pierside for about 47 months, according to Vice Chief of Naval Operations Adm. Bill Moran. On March 17, the Navy issued a solicitation to private shipyards for the engineering overhaul of the Boise.

In a letter Monday to acting Navy Secretary Sean Stackley and Chief of Naval Operations Adm. John Richardson, Democratic senators Richard Blumenthal and Chris Murphy asked that the Navy accelerate the awarding of the contract and about $20 million in planning funds.

Work on the Boise is scheduled to start in January 2019, but the senators are “confident” work can begin in mid-2018. The senators suggest that the $20 million in planning funds could come from the $1 trillion spending bill signed by President Donald Trump last week. The bill includes $280 million more than what then-President Barack Obama requested for operation and maintenance funding for the Navy. Congress did not pass the fiscal year 2017 budget before Obama left office.

“Accelerating this crucial maintenance for the USS Boise will allow it to reenter the fleet ahead of schedule, recovering operational availability at a time when this critical capability is in high demand,” the senators said in their letter.

While the senators don’t specifically name Electric Boat in their letter, Blumenthal said by phone Monday that as much as $30 million could be saved by EB doing the work, and that it could get done much faster.

Hundreds of EB employees are currently involved in the overhaul of the USS Montpelier, the largest and most complex maintenance and modernization in the company’s history. Thus, the company already has the workers trained and in place to carry out work on the Boise, Blumenthal said. Work on the Montpelier is expected to be complete in February 2018.

EB spokeswoman Liz Power said the company plans to submit a bid for the overhaul of the Boise, and if awarded the contract, it would “help us to sustain our staffing levels, the proficiency of our workforce, and would promote some efficiency of the Boise.”

Top military officials testified during a congressional hearing in February that budget constraints and uncertainty have forced them to make tough choices between addressing immediate operation needs and ensuring long-term readiness. It was announced at the time that five attack submarines were at risk of decertification due to overdue maintenance, though the names of the submarines were not listed.

Meanwhile, the Navy wants to add 80 ships, including 18 attack submarines, to its fleet. But it won’t reach those numbers without properly maintaining the ships it has, U.S. Reps. Joe Courtney, D-2nd District, and Rob Wittman, a Republican representing Virginia’s First Congressional District, said at a recent event.

Courtney and Wittman, who are the ranking member and chairman of the House Armed Services subcommittee with oversight of Navy shipbuilding, said they would be seeking additional money for ship maintenance in the fiscal 2018 defense budget.