Amphibious Force, Pacific Fleet

Amphibious Force, Pacific Fleet
US Navy · Public domain · source
Unit name	Amphibious Force, Pacific Fleet
Caption	USS Ashland during World War II operations
Dates	1917–1975
Country	United States of America
Branch	United States Navy
Type	Amphibious warfare
Role	Amphibious assault, expeditionary operations, sea-to-shore logistics
Garrison	Pearl Harbor, Hawaii
Notable commanders	Richard L. Conolly, Richmond K. Turner, Holland M. Smith

Amphibious Force, Pacific Fleet was the principal United States Navy formation responsible for planning, organizing, and executing amphibious operations in the Pacific Ocean theater from World War I through the Vietnam era. It coordinated with the United States Marine Corps, United States Army, United States Coast Guard, and Allied naval and ground forces including elements of the Royal Navy, Royal Australian Navy, Royal Canadian Navy, and New Zealand Navy. The formation developed doctrine, trained task forces, and led major amphibious campaigns during the World War II Pacific Theater and subsequent Cold War contingencies.

History

Established in the aftermath of evolving expeditionary needs, Amphibious Force roots trace to the Naval Operations of World War I and interwar experimentation such as the Fleet Problem series and the Maneuvers of 1935. Expansion accelerated after the attack on Pearl Harbor and the entry of the United States into the Pacific War. The force became central during the Island-hopping campaign that included operations across the Solomon Islands campaign, Gilbert and Marshall Islands campaign, Marianas campaign, and the Philippine campaign (1944–45). Postwar, the force adapted to Cold War requirements during the Korean War and Vietnam War, responding to crises like the Inchon landing coordination and littoral operations in support of Operation Frequent Wind. Its organizational identity shifted with Navy reorganization and the creation of unified commands, culminating in inactivation or redesignation during the 1970s as amphibious responsibilities migrated to commands such as Commander, Amphibious Forces, Pacific Fleet (PHIBPAC) and United States Pacific Fleet subordinate staffs.

Organization and Structure

The Amphibious Force was organized into numbered groups and task forces, commonly including Transports (AP/APA), Landing Ship, Tank (LST), Landing Ship, Medium (LSM), and Dock Landing Ship (LSD) units. Command relationships often placed it under the operational control of Commander-in-Chief, Pacific Fleet and in coordination with theater commanders such as Admiral Chester W. Nimitz and General Douglas MacArthur. Embarked landing forces included units from the 2nd Marine Division, 1st Marine Division, 3rd Marine Division, and Army formations like the 25th Infantry Division and 1st Cavalry Division (Airmobile). Staff sections mirrored naval planning standards with operations, intelligence, logistics, and communications sections working alongside Amphibious Corps staff elements.

Major Operations and Campaigns

Amphibious Force planners and commanders executed numerous large-scale assaults: the Guadalcanal Campaign, Tulagi landings, Battle of Tarawa, Operation Galvanic, Operation Forager, and the Battle of Leyte Gulf-linked amphibious phases including the Leyte landings. In the Iwo Jima campaign and Okinawa campaign, amphibious ships, prelanding bombardment coordination, and Naval Gunfire Support were essential. The force also supported postwar operations including Operation Magic Carpet and intervened in Cold War contingencies such as Operation Blue Bat-style amphibious readiness demonstrations, Korean War amphibious operations like Inchon, and humanitarian evacuations including aspects of Operation Frequent Wind during the fall of Saigon.

Ships and Equipment

Key ship types included attack transport classes (such as Bayfield-class and Haskell-class), attack cargo ships (Artemis-class), Landing Platform, Helicopter (LPH) conversions, and specialized amphibious warfare ships including Landing Ship, Tank (LST), Landing Craft, Vehicle, Personnel (LCVP), Landing Craft, Mechanized (LCM), and Landing Craft Utility (LCU). Fire support was provided by battleships like USS Missouri (BB-63), cruisers and destroyers equipped for fire missions. Innovations included amphibious tractors (LVT), use of Higgins boat types, and development of helicopter assault techniques incorporating Sikorsky H-34 and later CH-46 Sea Knight and UH-1 Iroquois for vertical envelopment.

Training and Doctrine

Doctrine evolved through documents such as Landing Operations Doctrine publications and experiential lessons codified after campaigns like Tarawa. Training centers at Little Creek, Virginia, Coronado, California, and Pearl Harbor hosted joint amphibious exercises with the United States Army Air Forces and later United States Air Force close-air support coordination. War games, fleet problems, and combined training with Allies, including exercises with the Royal Australian Air Force and Japan Maritime Self-Defense Force in the postwar era, refined amphibious assault, logistics, and casualty evacuation procedures.

Commanders and Leadership

Notable leaders included Admiral Richard L. Conolly, Admiral Richmond K. Turner, and Lieutenant General Holland M. Smith (USMC), who influenced doctrine and operational art for amphibious warfare. Other influential figures interacting with the force were Admiral William Halsey Jr., Admiral Raymond A. Spruance, and General Douglas MacArthur in combined operations. Staff officers and planners such as Ralph Davison and amphibious advocates in the Bureau of Ships shaped ship design and capability priorities.

Legacy and Impact

The Amphibious Force, Pacific Fleet left a lasting legacy on expeditionary warfare: shaping modern amphibious assault doctrine, influencing the design of purpose-built amphibious ships, and establishing joint doctrine practiced by United States Indo-Pacific Command and United States Fleet Forces Command. Lessons from its campaigns informed NATO amphibious planning and allied doctrines in Australia, Canada, and Japan. Memorials, museums, and surviving vessels such as preserved LSTs and museum ships commemorate operations. Its evolution contributed to contemporary concepts like distributed maritime operations and littoral maneuver, and its historical record remains central to studies of the Pacific War, joint operations, and naval innovation.

Category:United States Navy amphibious units Category:Military units and formations of the United States in World War II