NATIONAL HARBOR, Md. – The Columbia-class nuclear submarine program is on track to meet its expected deadline, but the Navy is keeping a nervous eye on budget negotiations on the Hill.

The program, which will replace the Ohio-class nuclear submarine fleet, is progressing towards the start of construction in 2021 – and patrols by 2031 – Vice Adm. David Johnson, principal military deputy assistant secretary of the Navy  for research, development and acquisition, said at the annual Navy League Sea-Air-Space conference Tuesday. 

But, he acknowledged, the current budget uncertainty could throw a wrench into that situation, particularly with the possibility that the government could spend the rest of fiscal year 2017 operating under a continuing resolution, or CR.

Click here to see more coverage from the 2017 Navy League Sea Air Space conference.  

Under a CR, budget levels are frozen at the previous year's figures, unless a program is given a special anomaly exception from Congress. In a past CR, the Columbia-class was given that pass by Congress, but even so, Johnson is taking nothing for granted this year – or next year.           

"The issue for Columbia is, let's say we got all the [funding] for the year," Johnson told reporters after his speech. "Then we have the same thing in 1 October, 2017. … It's not a sustainable, long-term strategy. That's the issue. 

"We can execute, but we need a budget," he added. 

During the panel, Johnson reiterated concerns put forth by the department that without a major increase in funding, the Columbia program will eat into the current shipbuilding plan for the Navy – let alone plans to get to 355 ships, something more in line with what President Donald Trump has indicated he supports.

However, Johnson said the budget questions are not having an impact on how the Navy is negotiating contracts with General Dynamics Electric Boat, the primary contractor for Columbia, nor with Huntington Ingalls Industries Newport News Shipbuilding, which will build roughly a third of each Columbia.

"That work is progressing on plan. The contract negotiations are very close to being done, and they are not at all impacted by a CR or any of that," Johnson told reporters. "It’s just straight work in the business of designing and building submarines."

The U.S. plans to design and build 12 Columbia-class submarines for a total acquisition cost of $100 billion in 2017 dollars – or $128 billion, as measured in total year dollars through the program, which stretches into the mid-2030s.