Naval buildup requires sustained political support.

* The Navy is pushing for a 355-ship fleet, far above the current level of 276. Achieving that goal would likely take decades and require a major boost in shipbuilding and operating budgets, lawmakers and analysts said.

The Congressional Budget Office estimated that reaching the new force structure target over a 30-year period would cost the service an average of $26.6 billion in 2017 dollars per year for ship construction--more than 60 percent above the average amount Congress has appropriated for that purpose over the past 30 years, and 40 percent more than the amount appropriated for 2016.

Personnel and operating costs would also soar, the office noted in a recent report, "Costs of Building a 355-Ship Navy."

"More ships would require more sailors; recruiting and training those sailors would require more civilian and military positions onshore; additional ships would lead to larger maintenance budgets; and those extra ships and crews would consume more fuel and supplies," it said.

The cost to build and operate the fleet would average $102 billion per year in 2017 dollars through 2047, more than onethird greater than the amount appropriated in fiscal year 2016, the report said.

Bryan Clark, an analyst at the Center for Strategic and Budgetary Assessments, said the Navy could potentially reach 355 ships at less cost than the CBO projected.

The CBO assumed that all of the additional ships in the larger Navy would come from new construction. But the service could help increase force levels by not retiring ships as quickly as...