San Antonio-class amphibious transport dock

The San Antonio class is the U.S. Navy's new primary class of amphibious transport dock (LPD) warships for the first third of the 21st century. These warships are to replace the older Austin class LPDs (including Cleveland and Trenton sub-classes), as well as the Newport class tank landing ships, and the Charleston class amphibious cargo ships, that has already been retired.

Twelve ships of the San Antonio class were proposed, but only eleven funded, with one cancelled due to budget cuts and cost overruns. Their original target price was $890 million; as built, their average cost is $1.6 billion. eight warships of this class are in service with the U.S. Navy.

Design and development
The class's increased vehicle and substantial cargo carrying capacity will make it a key element of 21st century Amphibious Ready Groups, Expeditionary Strike Groups, or Joint task forces. The ships of the new class integrate the latest in shipbuilding and naval warfare technologies to support current and future U.S. Marine Corps warplanes, and both air cushion landing craft or conventional landing craft.

The San Antonios are designed to be the most survivable amphibious ships ever put to sea. Their design incorporates state-of-the-art self-defense capabilities; and includes facilities for command and control, communications, computers, and intelligence (C4I). They also have a reduced radar cross-section designed in. Reduced operational costs and an improved capability to incorporate technological advances over their estimated 40-year service lives are also essential design objectives. The Advanced Enclosed Mast/Sensors, which enclose the ship's radars and communications antennas, characterize the ship's distinctive profile. The San Antonio class was largely designed with the metric system, specifying millimeters and meters for linear dimensions. This is the first major U.S. Navy ship class to be built this way. Most of their machinery remains in U.S. customary units.

The ships of the class can carry Landing Craft, Air Cushioned (LCACs), the Shipboard Wide Area Network with over 762 fiber optic drops, Total Ship's Training System, Integrated Bridge System, Engineering Control System, and Damage Control System all serve to ensure that sailors and Marines will be able to fully perform their expeditionary warfare missions. The San Antonios also incorporate the latest quality of life standards for the embarked Marines and sailors, including the sit-up berth, ship services mall, and Learning Resource Center/Electronic Classroom with the flexibility to accommodate sailors and Marines of both sexes as part of the crew and embarked troops.

The U.S. Department of Defense Department's Director of Operational Test and Evaluation (DOT&E), stated in 2010 that the ships are 'capable of operating “in a benign environment,” but not effective, suitable and not survivable in a combat situation'. The DOT&E found in 2011 that the class's first ship, USS San Antonio, had several deficiencies which rendered it "not operationally effective, suitable, or survivable in a hostile environment". San Antonio has experienced several construction related issues.

United States senator Kay Hagan has asked if the LPD-17 construction line ought to be extended to a 12th ship as a bridge to building the LX(R) (formerly LSD(X)) on the same hull, but the USN has indicated that the requirements of the LX(R) have not yet been settled and that the LPD-17 hull might be too large for such a mission. However Commandant James F. Amos has also endorsed dropping LSD in favor of continued LPD production.

Chief of Naval Operations Greenert is considering using some of the extra space in the San Antonio class to mount modular equipment in the same fashion as the Littoral combat ship. As part of their bid to offer "Flight II" LPD-17s for the Dock landing ship replacement contract, HII has suggested fitting out the ships to carry the Aegis Ballistic Missile Defense System.