The U.S. Navy said that it awarded General Dynamics NASSCO a $106.2 million contract modification to buy materials for a fifth Expeditionary Mobile Base ship, and to support its construction.

The ship will go together at NASSCO’s Barrio Logan shipyard.

The NASSCO-built ships previously went by the names Mobile Landing Platform and Afloat Forward Staging Base. Planners see the ships as military bases at sea, supporting amphibious landings on hostile shores.

Money will be used to buy long-lead-time material, including unspecified interior components; steel plates; piping; ventilation and machinery insulation; heating, ventilation and air conditioning components; emergency switchboards; piping; valves; steel shapes; a ballast water treatment system; an aqueous film forming system; and a knuckle-boom crane. The sum will also support engineering and non-production support.

Some $82.5 million of the funds came from the 2016 defense budget. The federal government began its 2017 fiscal year on Oct. 1.

Work is expected to be complete by March.

Shares of NASSCO parent General Dynamics trade on the New York Stock Exchange under the symbol GD.

The Naval Sea Systems Command (aka NAVSEA) of Washington, D.C. awarded the deal.