The U.S. Navy said that it awarded General Dynamics Nassco $7 million to cover additional maintenance work on the Wasp-class amphibious assault ship USS Boxer. Work is expected to be completed by December 2015.

Amphibious assault ships carry U.S. Marines, their landing craft and certain aircraft, including Harrier jump jets. With their large, flat decks, the ships resemble small aircraft carriers. The Wasp class is old-school when it comes to propulsion, with boilers producing steam to run its turbines.

In addition to repairing Navy ships, the Nassco business of General Dynamics (NYSE: GD) builds Navy auxiliary ships and commercial vessels.

The Southwest Regional Maintenance Center awarded the deal.