The U.S. Navy is one step closer to receiving two new expeditionary fast transport vessels, the branch announced.

In a statement on construction progress for the boats, the Navy recognized the keel authentication for the future USNS City of Bismarck and the start of fabrication for the future USNS Puerto Rico.

For the first vessel, former North Dakota Attorney General Robert O. Wefald signed off on USNS City of Bismarck by welding his initials into the keel plate.

For USNS Puerto Rico, primary contractor Austal USA began the fabrication of the hull. Austal first received a contract to build the ship in September 2016.

"As we mark these milestones, the program is benefitting from serial production efficiencies at all stages of the construction process," Capt. Henry Stevens said in a press release. "Our industry and Navy teams are committed to delivering these highly-capable platforms, and today's milestones mark our progress in delivering two more ships."

Expeditionary Fast Transport ships are vessels being designed for fast intra-theater transportation of troops, military vehicles and other supporting equipment. Austal has been contracted to deliver the ships to the Navy in addition to the U.S. Army.

The ships are capable of carrying 600 short tons across 1,200 nautical miles at an average speed of 35 knots. They also come equipped with a flight deck for helicopter operations.

According to the Navy, the design will make the ships ideal for a wide range of missions including humanitarian assistance, disaster relief and overseas contingency operations.