Strategic Sealift

Strategic Sealift (PM3)
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Our Prepositioning Program is an essential element in the U.S. military's readiness strategy. Afloat prepositioning strategically places military equipment and supplies aboard ships located in key ocean areas to ensure rapid availability during a major theater war, a humanitarian operation or other contingency. MSC's 49 prepositioning ships support the Army, Navy, Air Force, Marine Corps and Defense Logistics Agency.

Prepositioning ships provide quick and efficient movement of military gear between operating areas without reliance on other nations' transportation networks. These ships give U.S. regional combatant commanders the assurance that they will have what they need to quickly respond in a crisis - anywhere, anytime. During a contingency, troops are flown into a theater of operations to rapidly employ the cargo from these ships.

Many of MSC's prepositioning ships are able to discharge liquid, containerized or motorized cargo both pier side or while anchored offshore by using floating hoses and shallow-draft watercraft, called lighterage, that are carried aboard. This allows cargo to be ferried to shore in areas where ports are non-existent or in poor condition and gives the nation's military forces the ability to operate in both developed and undeveloped areas of the world.

Prepositioning ships include a combination of U.S. government-owned ships, chartered U.S. - flagged ships and ships activated from the Maritime Administration's Ready Reserve Force. All prepositioning ships are operated by U.S. civilian mariners who work for ship operating companies under contract to the federal government.

While most active ships in MSC's Prepositioning Program strategically place combat gear at sea, there are other ships, including:

  • The Mobile Landing Platform, a new class of ships designed to serve as a mobile sea-base option that provides our Navy fleet with a critical access infrastructure supporting the flexible deployment of forces and supplies
  • An offshore petroleum distribution system ship that can deliver fuel from up to eight miles offshore; and
  • Two aviation logistics support ships that are activated as needed from reduced operating status to provide at-sea maintenance for Marine Corps fixed- and rotary-wing aircraft

Ship Types

Maritime Prepositioning Force ships strategically position supplies for the U.S. Marine Corps at sea. These ships are laden with a variety of Marine Corps equipment and supplies, including tanks, ammunition, food, water, cargo, hospital equipment, petroleum products and spare parts - ready for rapid delivery ashore when needed.

MPF ships are organized into two Maritime Prepositioning Ship (MPS) squadrons, each comprising four to six MPF ships as well as additional prepositioning ships dedicated to other military services. Each MPS squadron carries sufficient equipment and supplies to sustain more than 16,000 Marine Expeditionary Brigade and Navy personnel for up to 30 days.

Army Prepositioned Stock-3 ships strategically place U.S. Army combat equipment at sea to supply and sustain deployed U.S. troops during national crises. Six of the APS-3 ships are government-owned cargo ships, called large, medium-speed, roll-on/roll-off ships, or LMSRs. Each ship has a cargo-carrying capacity of more than 300,000 square feet.

LMSRs are ideal for the rapid loading and off-loading of Army wheeled and tracked vehicles, as well as other outsized Army equipment. A series of internal and external ramps makes this possible, and shipboard cranes allow cargo to be lifted without relying on local port infrastructure. In addition to LMSRs, APS-3 ships include two container ships that store ammunition at sea for the Army.

Navy, Defense Logistics Agency and Air Force ships (NDAF) are the most diverse subset of MSC's prepositioning program. These ships operate around the world in support of the Department of Defense services and agencies.


Our Sealift Program provides high-quality, efficient and cost-effective ocean transportation for the Department of Defense and other federal agencies during peacetime and war. More than 90 percent of U.S. war fighters' equipment and supplies travels by sea. The program manages a mix of government-owned and long-term-chartered dry cargo ships and tankers, as well as additional short-term or voyage-chartered ships. By DOD policy, MSC must first look to the U.S - flagged market to meet its sealift requirements. Government-owned ships are used only when suitable U.S.-flagged commercial ships are unavailable.

Ship Types

Two high-speed transport vessels recently acquired by our Navy also belong to MSC. USNS Guam (HST 1), formerly MV Huakai, will replace the high-speed vessel Westpac Express, whose mission is to transport military personnel and cargo for the 3rd Marine Expeditionary Force between Okinawa and other U.S. Pacific Command training sites. The specific mission of USNS Puerto Rico (HST 2) is still being evaluated.

U.S.-flagged commercial tankers, under long-term charter to MSC, transport refined petroleum products for DOD, primarily between commercial refineries and storage and distribution facilities worldwide. Our tankers also perform unique missions such as refueling the National Science Foundation's McMurdo Station in Antarctica and the U.S. Air Force early warning station at Thule Air Base, Greenland.

During wartime or other contingencies, our Navy charters dry cargo ships under contract to MSC to move cargo as needed. These ships carry items that are too large to fit in containers, such as engineering and construction equipment, military vehicles, aircraft and ammunition.

With a shrinking U.S. merchant fleet, the importance of ready and available surge vessels increases each year. The Ready Reserve Force, owned and maintained by the Maritime Administration, provides a resource to offset the shortage of militarily useful U.S.-flagged ships. The RRF consists of fast sealift ships, roll-on/roll-off ships, lighter aboard ships, heavy lift ships, crane ships and government-owned tankers. Maintained in four-, five-, 10- or 20-day readiness status, these ships are activated when needed, fully crewed and placed under the operational control of MSC in support of U.S. wartime, humanitarian and disaster-relief operations. RRF ships are also used for some military exercises.