Amphibious Construction Battalion One

Amphibious Construction Battalion One, commonly abbreviated ACB-1 or PHIBCB-1, is a United States Navy amphibious construction unit headquartered at Naval Amphibious Base Coronado in California. It is described as the last remaining United States unit of its type and has a sister formation, Amphibious Construction Battalion Two, based at Naval Amphibious Base Little Creek in Virginia. Although its heritage is rooted in the Naval Construction Battalions, the unit is not a commercial construction company or consumer-facing brand. Its identity is that of a specialized military formation within the Navy’s Seabee and Naval Construction Force structure. The battalion’s central mission is to move combat cargo, bulk fuel, and water between ships and shore when conventional port infrastructure is unavailable, damaged, inadequate, or tactically unsuitable. It also supports tactical camp operations and expeditionary logistics for Amphibious Ready Groups, Marine Expeditionary Forces, brigade-sized formations, Combined or Joint Logistics Over-the-Shore operations, and Maritime Prepositioning Force missions. Its capabilities include the operation and placement of pontoon structures, causeways, barges, lighterage, temporary piers, and related ship-to-shore systems. These functions allow naval and Marine forces to receive supplies without relying entirely on established harbors. The unit was commissioned at Camp Peary, Virginia, on 16 July 1943, as the 104th Naval Construction Battalion. During the Second World War, the 104th served in the Southwest Pacific and supported construction and logistics activity in New Guinea, Australia, and the Philippines. Its wartime work ranged from airfield and base construction to broader naval facilities and operational infrastructure. The battalion was deactivated in December 1945, but it was reactivated in January 1947 with a more explicit amphibious role involving pontoon assembly and placement, beach rehabilitation, harbor development, salvage, and reservist training. In October 1950, the 104th and 105th Naval Construction Battalions were redesignated Amphibious Construction Battalions One and Two. ACB-1 subsequently supported major United States operations in Korea, Vietnam, the Persian Gulf, Somalia, Iraq, and humanitarian relief missions. During the Korean War, its detachments helped establish and operate temporary waterfront infrastructure at Inchon and Wonsan, supported the movement of Marine forces, and undertook specialized missions such as the construction of an emergency landing strip on Yo Do. The battalion also participated in Operation Passage to Freedom in 1954 and returned to Vietnam during the Vietnam War. In the post-Cold War period, ACB-1 deployed early in support of Operation Desert Shield, assisting the offload of Maritime Prepositioning Squadron ships for I Marine Expeditionary Force. It later supported the Naval Support Element in Somalia, where it helped unload prepositioning ships, rehabilitate port facilities, and provide fuel and water. In 2003, personnel associated with ACB-1 and ACB-2 supported operations from Kuwait, established a large logistics support area, assisted with the download of multiple Maritime Prepositioning Force ships, and helped move cargo and ammunition. In 2005, the unit participated in Operation Unified Assistance following the Indian Ocean tsunami. Its continuing relevance lies in providing mobile, expeditionary access to shore and sustaining forces in environments where fixed logistics networks cannot be assumed.

Amphibious Construction Battalion One traces its history to the 104th Naval Construction Battalion, commissioned at Camp Peary, Williamsburg, Virginia, on 16 July 1943. The unit was sent to Camp Endicott in Gulfport, Mississippi, and subsequently assigned to the VII Amphibious Group in the Southwest Pacific. During the Second World War it operated in the Milne Bay area of New Guinea, Australia, and the Leyte-Samar area of the Philippines. Its work included naval base construction, airfield-related projects, and other shore infrastructure. The battalion was deactivated in December 1945 after the end of the war. The 104th was reactivated in January 1947. Its renewed duties emphasized amphibious engineering rather than only general construction: assembling and placing pontoon structures, rehabilitating beaches, developing harbors, conducting salvage, and training reservists in these functions. In October 1950, the Navy formally redesignated the 104th and 105th Naval Construction Battalions as Amphibious Construction Battalions One and Two, recognizing their specialized capabilities. During the Korean War, ACB-1 detachments supported the Inchon landing and subsequent operations on Korea’s east coast. A pontoon causeway was brought into Inchon Harbor shortly after the landing to provide a tide-level route from ship to shore. The battalion later supported the movement of the 1st Marine Division at Wonsan by building piers and assisting with ship unloading. One detachment also conducted a hazardous rail-recovery mission near Inchon, freeing locomotives trapped behind damaged rail lines and returning them to friendly control. In another operation, a detachment constructed an emergency landing strip on Yo Do island; the runway was named Briscoe Field. ACB-1 was involved in Operation Passage to Freedom in 1954, when it deployed with Task Force 90 to support the movement of people from North Vietnam to the south. The battalion returned to Vietnam in 1964 as the first Naval Construction Force unit to deploy during the Vietnam War. Its Vietnam-era service contributed to the unit’s later recognition through expeditionary and campaign awards. The battalion entered the post-Cold War period as a key maritime logistics formation. In August 1990 it became the first Naval Construction Force unit to deploy to Saudi Arabia for Operation Desert Shield. It helped offload Maritime Prepositioning Squadron vessels and provided technical support to joint forces. In December 1992, it deployed to Mogadishu as part of the Naval Support Element for operations in Somalia. There it unloaded five Marine prepositioning ships, helped restore port facilities, and supplied fuel and water. Additional offload preparation deployments followed in 1994 and 1995 in response to concerns about renewed Iraqi aggression in the Persian Gulf. In early 2003, ACB-1 and ACB-2 deployed to Kuwait Naval Base in support of Operation Enduring Freedom and Operation Iraqi Freedom. The deployment included the movement of more than 1,200 short tons of cargo by strategic airlift, construction of a logistics support area capable of housing thousands of personnel, and the download of 13 Maritime Prepositioning Force ships associated with three maritime prepositioning squadrons. A small ACB-1 detachment also moved into Iraq to assist Naval Mobile Construction Battalions with anchoring a floating bridge. In 2005, the unit supported Operation Unified Assistance, the United States humanitarian response to the Indian Ocean tsunami. The battalion’s institutional role has remained centered on expeditionary access. Rather than operating as a conventional fixed-site contractor, it provides naval and Marine forces with the temporary waterfront, lighterage, cargo-handling, fuel, water, and camp-support capabilities needed to operate from undeveloped or damaged shorelines. Its awards and service record include recognition from the Korean, Vietnam, Southwest Asia, and humanitarian operations, as well as a Presidential Unit Citation and other unit commendations. It is based at Coronado, California, and remains associated with the Navy’s Seabee and amphibious logistics structure.

1. 2005Indian Ocean tsunami response

   ACB-1 participated in Operation Unified Assistance, the United States military humanitarian response to the tsunami.

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2. 2003Kuwait and Iraq logistics mission

   The unit helped establish a large logistics support area and supported the offload of 13 Maritime Prepositioning Force ships.

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3. 1992Somalia deployment

   ACB-1 supported port operations, ship offload, and fuel and water distribution in Mogadishu.

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4. 1990Operation Desert Shield deployment

   The battalion deployed to Saudi Arabia and supported Maritime Prepositioning Force logistics for Marine units.

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5. 1954Operation Passage to Freedom

   ACB-1 supported Task Force 90 during the relocation of civilians from North Vietnam to South Vietnam.

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6. 1950Redesignated Amphibious Construction Battalion One

   The Navy redesignated the 104th Naval Construction Battalion as ACB-1 in recognition of its specialized amphibious capabilities.

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7. 1947Unit reactivated with an amphibious mission

   The reactivated battalion assumed duties involving pontoon structures, beaches, harbors, salvage, and training.

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8. 1945World War II service concludes

   After service in the Southwest Pacific and the Philippines, the 104th Naval Construction Battalion was deactivated in December.

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9. 1943104th Naval Construction Battalion commissioned

   The unit was commissioned at Camp Peary, Virginia, establishing the lineage of the future ACB-1.

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A specialized United States Navy Seabee formation positioned as an expeditionary logistics and amphibious construction capability for contested or infrastructure-limited shore environments.

• Ship-to-shore logisticsExpeditionary logistics

  The battalion transports combat cargo, bulk fuel, and water from ships to shore, particularly where ports are unavailable or damaged. This capability supports amphibious ready groups, Marine expeditionary forces, brigade-sized formations, and joint logistics operations.

• Pontoon causeways and floating waterfront systemsAmphibious construction

  ACB-1 operates and supports pontoon structures, causeways, piers, and barges that create temporary connections between offshore vessels and shore. These systems provide a flexible substitute for permanent port infrastructure during expeditionary operations.

• Maritime Prepositioning Force offload supportMilitary logistics

  The unit assists with the rapid discharge of prepositioned ships carrying vehicles, ammunition, fuel, supplies, and other equipment. Its work enables Marine and joint forces to access stored combat power in overseas theaters.

• Expeditionary camp and port operationsExpeditionary engineering

  Beyond waterfront work, ACB-1 supports tactical camp operations, port rehabilitation, harbor development, beach restoration, salvage, and related shore-side engineering tasks required to sustain deployed forces.

• 2005Operation Unified Assistance

  Indian Ocean region

  The unit participated in the United States military humanitarian response to the Indian Ocean tsunami.

  Outcome. ACB-1’s participation extended its expeditionary construction and logistics capabilities to disaster relief.

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• 2003Operation Enduring Freedom and Operation Iraqi Freedom

  Kuwait · Iraq

  ACB-1 and ACB-2 established logistics infrastructure in Kuwait, supported prepositioned-ship offloads, and assisted with a floating bridge in Iraq.

  Outcome. The deployment supported the movement and sustainment of United States and coalition forces.

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• 1992Somalia intervention

  Somalia

  ACB-1 supported the Naval Support Element in Mogadishu by unloading ships and restoring port and sustainment functions.

  Outcome. The deployment demonstrated the battalion’s ability to establish expeditionary logistics through an operational port.

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• 1990Operation Desert Shield and Desert Storm

  Saudi Arabia · Persian Gulf

  The battalion supported Maritime Prepositioning Force ship offloads and joint logistics in the Gulf region.

  Outcome. The unit received a Navy Meritorious Unit Commendation associated with Desert Storm service.

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• 1964Vietnam War

  Vietnam

  ACB-1 returned to Southeast Asia as the first Naval Construction Force unit to deploy during the Vietnam War.

  Outcome. The battalion received Vietnam-related campaign and service recognition.

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• 1954Operation Passage to Freedom

  Vietnam

  The battalion served with Task Force 90 during the movement of people from North Vietnam to South Vietnam.

  Outcome. The operation became part of the unit’s Vietnam-era service record.

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• 1950Korean War

  South Korea

  ACB-1 supported the Inchon and Wonsan operations with causeways, piers, ship unloading, rail recovery, and emergency airfield construction.

  Outcome. The unit received significant Korean War recognition, including a Presidential Unit Citation and a Republic of Korea Presidential Unit Citation.

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• 1943World War II Pacific operations

  New Guinea · Australia · Philippines

  As the 104th Naval Construction Battalion, the unit supported Pacific-area base and airfield construction and other naval shore projects.

  Outcome. The wartime lineage was preserved through subsequent reactivation and conversion to an amphibious construction role.

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• 2005Operation Unified Assistance humanitarian deployment

  The unit participated in the United States military response to the Indian Ocean tsunami.

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• 2003Kuwait and Iraq logistics deployment

  ACB-1 and ACB-2 supported operations from Kuwait, established a major logistics support area, assisted with Maritime Prepositioning Force ship offloads, and sent a detachment forward to support a floating bridge.

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• 1992ACB-1 supports the Somalia intervention

  The battalion arrived in Mogadishu as part of the Naval Support Element, helping unload prepositioning ships, restore port operations, and distribute fuel and water.

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• 1990First Naval Construction Force unit into Operation Desert Shield

  PHIBCB ONE deployed to Saudi Arabia and supported the offload of Maritime Prepositioning Squadron ships for Marine forces during Operation Desert Shield.

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• 1964ACB-1 deploys to Vietnam

  The battalion returned to Southeast Asia as the first Naval Construction Force unit to deploy during the Vietnam War.

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• 1954Operation Passage to Freedom deployment

  ACB-1 deployed as part of Task Force 90 during the movement of civilians from North Vietnam to South Vietnam after the Geneva arrangements.

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• 1950Unit redesignated Amphibious Construction Battalion One

  The 104th Naval Construction Battalion was redesignated ACB-1 after the Navy identified its specialized amphibious construction and waterfront capabilities.

  Leadership changeOther
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• 1950ACB-1 supports the Inchon and Wonsan operations

  The battalion used pontoon and pier capabilities to support amphibious logistics at Inchon and later Wonsan during the Korean War.

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• 1944104th Naval Construction Battalion supports Pacific operations

  The battalion operated in New Guinea, Australia, and the Philippines, performing construction and base-support work during the Second World War.

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• 1943104th Naval Construction Battalion commissioned

  The unit was established at Camp Peary, Virginia, as the 104th Naval Construction Battalion, beginning the lineage that later became Amphibious Construction Battalion One.

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1. Amphibious Construction Battalion 1