LPD 17 San Antonio-class Amphibious Transport Dock

Amphibious troop transport and cargo carrying vessel.

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History

In January of 1993 The Defense Acquisition Board approved the construction of the LPD (Amphibious Transport Dock) 17 San Antonio class ships. The LPD 17 program was very ambitions; the class was developed to replace 4 existing classes of ships - LPD 4 Austin class amphibious dock, LST 1179 Newport class Landing Ship, Tank, Charleston class amphibious cargo ships (LKA 113), and the Anchorage class (LSD 36) dock landing ships. Ultimately, twelve LPD 17 class ships would replace and duplicate the services and capabilities of 41 other, less capable vessels. Avondale shipyards was awarded the contract for the first of the class (USS San Antonio) in December of 1996 with an option to purchase two more. Disputes surrounding the contract award caused a delay in the official contract awarding until April of 1997and initial construction did not begin until August of 2000. The San Antonio was launched in July of 2003, and commissioned in January of 2006. As part of the contract negotiations in 1996 the navy committed to building twelve LPD 17 ships, with eight being built at the Litton Avondale (Northrop-Grumman) shipyards, while four would be built at the General Dynamics Bath Iron Works facility. In 2002 the Navy modified this agreement, redirecting the construction of the four Bath Iron Works LPD 17s to Northrop-Grumman, while assigning Bath Iron Works the responsibility or manufacturing four Arleigh Burke (DDG 51) destroyers. The San Antonio class LPDs incorporate a number of stealthy characteristics in their construction. Attention was specifically given to the ships? hull lines, with a deliberate attempt made to reduce the number of right angles built into the hull and superstructure (squared surfaces promote radar reflection, whereas the angles incorporated into the San Antonio hull re-direct reflected radar energy. In addition, the LPD 17 series is the first class to incorporate the Advanced Enclosed Mast/Sensor (AEM/S) System. On more conventional ships, electronic sensors (radios, radars, radar warning receivers) were mounted on exposed masts. In the AEM/S system aboard the San Antonio, both of the ship's sensor masts are enclosed in large hexagonal structures. While these structures do degrade the performance of the covered sensors to some degree, their primary function is to absorb incoming electronic radiation and redirect it. In addition, the AEM/S covers also protect the covered electronic sensors from the elements, reducing maintenance costs. In addition to the AEM/S, the LPD 17 class of ships will also incorporate the Mk 2 Ship Self Defense System (SSDS.) The SSDS integrates all of the ship's electronic sensors (radars, ESM sensors) with the ship's weapon systems and electronic countermeasures, providing a single, integrated defensive network. Unfortunately, all of these improvements have a price; originally slated to cost $617 million, the cost of the first LPD 17 ballooned to more than $800 million. While the LPD 17 represents an advancement in naval amphibious warfare technology and capability, there are some trade-offs. The San Antonio class LPDs lack the dual bridge flagship command and control capability of some of the older LPD 4 ships. The San Antonio lacks the same sea-lift transport capacity as the Anchorage class (LSD 36) landing ships (3 LCAC/LCU on the LSD 36 compared to 2 LCAC/1 LCU on the LPD 17) and it lacks the bow doors required to offload cargo on the beach. Finally, the LPD 17 lacks the same heavy, over-the-side cargo handling capability of the Charleston class amphibious cargo ships. Currently, there is one ship of this class (USS San Antonio) in commissioned service.

Description

General Characteristics:
The San Antonio-class amphibious transport docks are 684 feet long, have a beam of 105 feet, and draw 23 feet of water. They are Panama Canal capable. Their displacement is 25,300 tons at full load their naval (crew) compliment is 332 enlisted and 28 officers (their marine (troop) compliment is 633 enlisted and 66 officers.) They have a top speed of 22 knots.

The San Antonio has sufficient hangar space to accommodate two CH-53E Super Stallion helicopters or MV-22 Osprey tilt rotor aircraft, or up to four CH-46E Sea Knight, UH-1 or AH-1 helicopters. An equal number of aircraft can be stationed on open-air flight deck spots.

The well deck on the San Antonio is similar to that of the LHD 1 Wasp class amphibious assault ships, in which a ramp can deploy to allow for wither the wet launch of LCU type landing craft or dry launches of LCAC/AAV transports. The standard LCAC (Landing Craft Air Cushion) compliment is two, though a single LCU can be embarked as a substitute.

To support troops ashore, the San Antonio class ships are equipped with a 24-bed medical treatment facility, 2 surgical operating rooms, 2 dental operating rooms, 25,000 square feet of deck space for vehicles, and 36,000 cubic feet for bulk cargo.

Propulsion:
The San Antonio class LPDs are powered by four Colt Pielstick sequentially turbocharged PC 2.5 diesel engines producing 41,600 horsepower combined. Propulsion is provided by two shafts fitted with controllable pitch screws.

Electronics:
The San Antonio class LPDs feature an SPS-48E C/D band air search radar, SPS-67(v)3 G-band surface search radar, an SPS-64(v)9 I-band navigation radar, and an SPQ-9B I-band fire control radar.

Command and control systems include the SPQ-14(v) Advanced Sensor Distribution System, the USQ-119E (V) 27 - maritime Global Command and Control System (GCCS-M), KSQ-1 Amphibious Assault Direction System, Mk 91 Guided Missile command and Control System, and the USG-2 (V) Cooperative Engagement Transmission Processing Set.

Defensive and electronic warfare systems include the Mk 2 mod 2 Ship Self-Defense System, Mk 36 SRBOC chaff launcher, Mk 53 Nulka radar homing missile decoy system, SLQ 32(v)2 electronic warfare system, and the SLQ-25A, Nixie passive, electro-acoustic torpedo decoy system.

Armament:
The San Antonio class transports are quipped with two Mk 31 mod 1 RAM (RIM 116 rolling airframe missile) short-range anti-air missile launchers, two Mk 26 mod 17 30mm bushmaster chain cannons, and two Mk 26 mod 17 .50 caliber machine guns.