General Dynamics NASSCO said on Oct. 14 that it started construction on the fourth in a series of expeditionary warfare support ships. The U.S. Navy signed a $498.1 million deal to build the ship in June.

The 784-foot ship — which the Navy expects by March 2018 — will be configured with a 52,000 square-foot flight deck and accommodations for up to 250 personnel. The ship will be capable of supporting multiple missions including air mine countermeasures, counterpiracy operations, maritime security operations, humanitarian aid and disaster relief missions, as well as U.S. Marine Corps crisis response.

The ship is similar to the USNS Montford Point in its general design, with a low center section. However, it has a modification made to the ship that preceded it, the USNS Lewis B. Puller: the depressed center section of the ship serves as the base of a raised platform that can serve as a place to land helicopters.

The ships were originally called Mobile Landing Platforms and Afloat Forward Staging Bases, but the Navy gave them new names this summer.

The first two ships — those without raised platforms — will be called Expeditionary Transfer Docks.

The second two with platforms will be Expeditionary Base Mobile ships.

General Dynamics shares trade on the New York Stock Exchange under the symbol GD.