BATH, Maine — An omnibus spending bill unveiled Monday night by U.S. Senate negotiators will include $100 million to allow Bath Iron Works to begin planning for construction of a fifth DDG-51 destroyer.

Securing the funding “was a difficult feat,” U.S. Sen. Susan Collins, R-Maine, told the Bangor Daily News by phone Tuesday. But now that the $100 million has been secured, U.S. Navy officials are ready to sign a contract option to approve the Arleigh Burke-class destroyer. she said.

In June, the Department of Defense awarded contracts for nine Arleigh Burke-class guided missile destroyers, five to Ingalls Shipbuilding in Pascagoula, Miss., and four to BIW, with the option for a fifth.

The funding was included in the National Defense Authorization Act, which President Barack Obama signed in December, but Congress still had to allocate the funding.

Automatic federal spending cuts known as sequestration, which took effect in March 2013 after Congress failed to strike a budget and national debt reduction deal, resulted in a more than $300 million shortfall in funding for the fifth DDG-51.

Collins said she and U.S. Sen. Angus King, I-Maine, lobbied members of the Appropriations Committee to include the funding, which she described as particularly difficult given “a very constrained budget for the Department of Defense.”

But she said the fifth ship “is a win for taxpayers as well as for the Navy and Bath Iron Works.”

“Over time, the estimated savings for having a multi-year procurement is approximately $1.5 billion, because of economies of scale and predictability of employment,” Collins said. “That’s the equivalent of a whole [destroyer].”

While not enough to pay the full cost of a fifth Arleigh Burke-class destroyer, approximately $300 million, the $100 million will allow Bath Iron Works to begin work on the hull, according to defense industry analyst Loren Thompson at the Arlington, Va.-based Lexington Institute.

Collins said she is confident the remaining $200 million can be secured.

“This funding is critical to the future work of the shipyard,” U.S. Reps. Mike Michaud and Chellie Pingree said in a joint release Monday night. “Eliminating this shortfall will help maintain the Navy’s readiness, and it’s yet another endorsement of the outstanding work being done by our shipbuilders in Bath.”

“Not only will this funding help contribute to greater stability for BIW’s workforce into the future, but it will also save taxpayer money and provide the Navy with another world-class ship to support our national security missions across the globe,” King said in a statement.

Securing the fifth destroyer will not immediately affect staffing levels at Bath Iron Works, shipyard spokesman Jim DeMartini said.