USS San Diego (LPD-22)

History

USS San Diego (LPD-22) is a San Antonio-class amphibious transport dock of the United States Navy. The ship is designed to transport Marines, vehicles, landing craft and aircraft for amphibious and expeditionary operations. It is the sixth ship of the San Antonio class.

The ship combines a floodable well deck for landing craft with a flight deck and hangar for helicopters and MV-22 Osprey tiltrotor aircraft. These facilities allow embarked Marine forces to move from ship to shore by surface craft or aircraft.

USS San Diego was awarded on June 1, 2006. According to the U.S. Navy's official ship history, the keel was laid on May 23, 2007. The ship was launched on May 7, 2010, and christened on June 12, 2010. Northrop Grumman Ship Systems is identified by the Navy as the builder.

During construction, San Diego was prepared for generator operation and sea trials during 2010 and 2011. NavSource records that the ship successfully completed Navy acceptance trials in November 2011 after a two-day sea trial. It was delivered to the Navy and placed in service on December 19, 2011.

San Diego made its maiden voyage from the Gulf Coast to California in 2012. It visited Naval Station Guantanamo Bay in March before arriving at its namesake city and initial homeport of San Diego on April 6. USS San Diego was commissioned on May 19, 2012.

Design

USS San Diego belongs to the first group of San Antonio-class amphibious transport docks. The class was developed as a modern replacement for several older amphibious warfare ship types and provides increased space for vehicles, landing craft and aviation operations. A San Antonio-class reference describes the ships as more than 25,000 tons at full load.

Amphibious facilities

The ship has a floodable well deck for surface assault craft. The Navy's official ship page lists capacity for two Landing Craft Air Cushion vehicles or one Landing Craft Utility. It also states a vehicle capacity of 14 Expeditionary Fighting Vehicles, reflecting the amphibious vehicle type planned when the ship was developed.

NavSource lists three vehicle decks with about 2,323 square meters of net vehicle space and two cargo and ammunition magazine areas totaling about 708 cubic meters. It also lists capacity for approximately 1,190 cubic meters of JP-5 aviation fuel and 38 cubic meters of motor gasoline.

Aviation facilities

The flight deck supports helicopter and tiltrotor operations. The Navy states that the ship can operate helicopters and the MV-22 Osprey. Its hangar maintenance facilities can accommodate one CH-53E, two CH-46 helicopters, one MV-22, or three UH-1/AH-1-family helicopters. Flight deck combinations listed for the class include two CH-53 helicopters, four AH-1/UH-1 helicopters, two MV-22 aircraft, or one AV-8B Harrier.

Propulsion and electrical systems

San Diego uses four medium-speed turbocharged marine diesel engines driving two shafts and two fixed-pitch propellers. The class reference identifies the engines as Colt-Pielstick diesels with a combined output of about 41,600 shaft horsepower. NavSource lists five 2,500 kW ship-service marine diesel generators and a zonal electrical distribution system.

Sensors and combat systems

NavSource lists the AN/SPQ-9B radar together with AN/SPS-48E and AN/SPS-73 radar systems. It also identifies the Ship Self-Defense System, Cooperative Engagement Capability, AN/SLQ-25A Nixie torpedo countermeasure, AN/SLQ-32Q(V)2 electronic warfare system, Mk 36 SRBOC decoy launchers and Mk 53 Nulka decoys. A class reference lists the later AN/SPS-48G designation instead of AN/SPS-48E, so the supplied material does not establish the exact date or current configuration of this radar aboard San Diego.

Armament

The documented defensive armament includes two Mk 46 30 mm gun systems and two Rolling Airframe Missile launchers. NavSource additionally lists two Mk 26 Mod 17 .50-caliber machine guns. Its equipment listing also records space and weight provision for a 16-cell Mk 41 vertical launching system rather than confirming an installed Mk 41 battery.

Medical facilities

NavSource lists two operating rooms, a 24-person hospital ward and capacity for up to 100 additional casualties. These facilities support the ship's expeditionary and amphibious mission.

Operational history

In February 2014, USS San Diego conducted an underway recovery test for NASA's Orion crew module in the Pacific Ocean. Navy divers worked with the ship to move the test module into the well deck, while an MH-60S helicopter also operated from the flight deck.

San Diego later deployed with the Makin Island Amphibious Ready Group. It returned to Naval Base San Diego on February 25, 2015, after a seven-month deployment in the U.S. 5th and 7th Fleet areas of responsibility. Later that year the ship completed an extended maintenance period at BAE Systems San Diego Shipyard.

During Rim of the Pacific 2016, San Diego participated in amphibious interoperability training with the Royal Australian Navy. An LCAC from San Diego entered the well deck of HMAS Canberra, Australian MRH-90 helicopters operated around San Diego's flight deck, and amphibious assault vehicles departed the ship during joint exercises.

In October 2016, the ship again supported NASA Orion recovery work. Divers and the ship tested a towing technique intended to move a boilerplate crew-module test article while reducing personnel requirements and improving recovery safety.

In 2017, San Diego conducted amphibious squadron and Marine expeditionary unit integration training before deploying with the America Amphibious Ready Group and the 15th Marine Expeditionary Unit. In December 2017 it departed Souda Bay, Greece, while supporting maritime security and theater security cooperation activities in the U.S. 6th Fleet area.

In January 2018, USS San Diego visited Naval Base Guam while operating with the America Amphibious Ready Group and 15th Marine Expeditionary Unit in the Indo-Asia-Pacific region.

By 2026, the Navy's official ship page listed Sasebo, Japan, as San Diego's homeport. On September 12, 2026, the ship departed Naval Base Guam after transiting Apra Harbor during routine operations in the U.S. 7th Fleet area.

Operators

• United States Navy: USS San Diego was commissioned on May 19, 2012. The Navy's ship page lists Sasebo, Japan, as its homeport.

Specifications (USS San Diego LPD-22)

General characteristics

• Type: San Antonio-class amphibious transport dock
• Full-load displacement: approximately 25,000-25,300 tons
• Length: 208 m (684 ft)
• Beam: 32 m (105 ft)
• Draft: approximately 7 m (23 ft)
• Ship's crew: 28 officers and 332 enlisted personnel according to the official Navy ship page
• Marine detachment: 66 officers and 633 enlisted personnel, expandable to about 800
• Propulsion: four medium-speed turbocharged marine diesel engines driving two shafts
• Propulsion power: approximately 41,600 shp for the class
• Propellers: two fixed-pitch propellers

Performance

• Maximum speed: more than 22 knots (about 41 km/h)

Amphibious and aviation capacity

• Well deck: two LCACs or one LCU
• Vehicle capacity: official ship page lists 14 Expeditionary Fighting Vehicles
• Hangar maintenance capacity: one CH-53E, two CH-46s, one MV-22, or three UH-1/AH-1-family helicopters
• Flight deck combinations: two CH-53s, four AH-1/UH-1s, two MV-22s, or one AV-8B Harrier

Armament

• Close-in guns: two Mk 46 30 mm gun systems
• Missile defense: two Rolling Airframe Missile launchers
• Machine guns: two Mk 26 Mod 17 .50-caliber machine guns listed by NavSource

Selected sensors and countermeasures

• Surface search and fire control radar: AN/SPQ-9B
• Air-search radar: AN/SPS-48-series; supplied sources differ between AN/SPS-48E and AN/SPS-48G designations
• Electronic warfare: AN/SLQ-32Q(V)2 listed by NavSource
• Torpedo countermeasure: AN/SLQ-25A Nixie
• Decoys: Mk 36 SRBOC and Mk 53 Nulka

Related equipment

• San Antonio class: the amphibious transport dock class to which USS San Diego belongs.
• LCAC: air-cushioned landing craft carried in the ship's well deck for ship-to-shore movement.
• MV-22 Osprey: tiltrotor aircraft supported by the ship's flight deck and hangar facilities.