US Navy's San Antonio-class ship, Somerset (LPD 25)

Huntington Ingalls Industries (HII) Ingalls Shipbuilding division has successfully delivered the ninth San Antonio-class amphibious transport dock ship, Somerset (LPD 25) to the US Navy.

The ninth ship has been named in honour of the United Airlines Flight 93 airline passengers, who forced hijackers to crash the airplane in Stonycreek Township in Somerset County, Pennsylvania, US, on 11 September 2001.

Ingalls LPD 17 programme director Mike Duthu said: "With Somerset, the navy is getting another very capable and adaptable amphibious warship designed and built to enable sailors and marines to accomplish their missions."

The San Antonio-class vessels will replace more than 41 ships currently in service with the US Navy. including the Austin-class (LPD 4), Anchorage-class (LSD 36), Charleston-class (LKA 113) and Newport-class (LST 1179) of amphibious ships.

Capable of carrying a crew up to 800, the LPD 25 can transport air cushion (LCAC) or conventional landing crafts, as well as helicopters and the Osprey tilt-rotor aircraft.

"The ninth ship has been named in honour of the United Airlines Flight 93 airline passengers."

The vessels will be used to support amphibious assault, special operations or expeditionary warfare missions for the US Navy.

Powered by four turbo-charged diesel engines to cruise at a speed of 22k, the San Antonio-class ship is 684ft-long with a displacement capacity of 24,900t, overall beam of 105ft and navigational draft of 23ft.

The vessel features AN/SLQ-25A Nixie-towed decoy system and the mk53 Nulka decoy launching system as well as ITT AN/SPS-48E 3D air search radar and AN/APQ-9B surface surveillance and tracking radar.

Currently, John P. Murtha (LPD 26) and Portland (LPD 27), the tenth and eleventh ships of the class are under construction and scheduled for completion in 2016 and 2017 respectively.

Image: US Navy’s San Antonio-class ship, Somerset (LPD 25), stationed at HII’s Avondale Shipyard. Photo: courtesy of Huntington Ingalls Industries.

Defence Technology