Construction begins on US Navy's 16th San Antonio-class amphibious transport dock

Huntington Ingalls Industries' Ingalls Shipbuilding division recently held a steel-cutting ceremony to mark the start of construction of the sixteenth San Antonio-class amphibious transport dock (LPD) ordered by the US Navy.

The future USS Philadelphia belongs to the San Antonio-class Flight II ships, which will replace the current US Navy dock landing ships (LSDs) USS Whidbey Island and USS Harpers Ferry.

The future Philadelphia will have an LOA of 684 feet (208.5 metres), a beam of 104 feet (31.9 metres), a draught of 23 feet (seven metres), and a displacement of 22,670 tonnes at full load. Four Colt-Pielstick diesel engines that each produce 40,000 hp (29,828 kW) will propel the ship to speeds of up to 22 knots.

The LPD is designed to support embarking, transporting, and landing US Marines and their equipment by conventional landing craft (LCU) or air-cushioned landing craft (LCAC). The well deck can accommodate either one LCU or two LCACs, and the ship's capabilities will be further enhanced by its flight deck and hangar, enabling the ship to operate a variety of helicopters and the MV-22 Osprey tilt-rotor aircraft.

Up to 699 marines and their equipment can be embarked in addition to the ship's own crew complement of 28 officers and 333 enlisted sailors. The San Antonio-class ships have slightly reduced troop-carrying capacity compared to the Austin-class amphibious transport docks they were built to replace, but the newer vessels offer significantly greater capacity for transporting vehicles compared to their predecessors.

The active self-defence armament will include two launchers for Rolling Airframe Missiles for use against airborne threats and two 30mm autocannon for dealing with surface threats. An advanced ship self-defence system (SSDS) will integrate the various onboard sensors to ensure the weaponry can quickly and automatically react to defend against air and missile attack.