The Mobile Landing Platform (MLP) is a type of amphibious assault ship

Amphibious assault ship

An amphibious assault ship is a type of amphibious warfare ship employed to land and support ground forces on enemy territory by an amphibious assault...

 being constructed for the United States Navy

United States Navy

The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

, with the first ship due to enter service in 2015. MLP ships are to serve as floating bases for amphibious operations, and operate as a transfer point between large ships and small landing craft

Landing craft

Landing craft are boats and seagoing vessels used to convey a landing force from the sea to the shore during an amphibious assault. Most renowned are those used to storm the beaches of Normandy, the Mediterranean, and many Pacific islands during WWII...

. Proof-of-concept testing began in 2005, with heavy lift ship

Heavy lift ship

A heavy lift ship is a vessel designed to move very large loads that cannot be handled by normally equipped ships. They are of two types: semi-submerging capable of lifting another ship out of the water and transporting it; and vessels that augment unloading facilities at inadequately equipped...

s serving as substitutes for the MLPs. General Dynamics

General Dynamics

General Dynamics Corporation is a U.S. defense conglomerate formed by mergers and divestitures, and as of 2008 it is the fifth largest defense contractor in the world. Its headquarters are in West Falls Church , unincorporated Fairfax County, Virginia, in the Falls Church area.The company has...

' National Steel and Shipbuilding Company

National Steel and Shipbuilding Company

National Steel and Shipbuilding Company, commonly referred to as NASSCO, is a shipyard in San Diego, California and Norfolk, Virginia and a division of General Dynamics. The shipyard specializes in constructing commercial cargo ships and auxiliary vessels for the US Navy and Military Sealift...

 was awarded a contract to design and build the first ship in late 2010, with construction beginning in July 2011. The United States Navy initially plans to acquire three vessels.

Design

The Mobile Landing Platform concept calls for a large auxiliary support ship to facilitate the 'seabasing

Seabasing

Seabasing is a naval capability that provides commanders with the ability to conduct selected functions and tasks at sea without reliance on infrastructure ashore. It describes the concepts and methods for sustaining large military forces during operations at large distances from traditional...

' of an amphibious landing

Amphibious warfare

Amphibious warfare is the use of naval firepower, logistics and strategy to project military power ashore. In previous eras it stood as the primary method of delivering troops to non-contiguous enemy-held terrain...

 force by acting as a floating base or transfer station that can be prepositioned off the target area. Troops, equipment, and cargo would be transferred to the MLP by large-draft ships, from where it can be moved ashore by shallower-draft vessels, landing craft like the Landing Craft Air Cushion (LCAC), or helicopters. In order to transfer vehicles to the larger ships to the MLP, the vessels were originally to be fitted with a Vehicle Transfer System; a ramp connecting the two ships alongside, and able to compensate for the movements of both vessels while underway.

A preliminary design by General Dynamics

General Dynamics

General Dynamics Corporation is a U.S. defense conglomerate formed by mergers and divestitures, and as of 2008 it is the fifth largest defense contractor in the world. Its headquarters are in West Falls Church , unincorporated Fairfax County, Virginia, in the Falls Church area.The company has...

 envisioned a ship that carried six LCACs, with the ability to turn-around (dock, unload or load, then launch) two landing craft simultaneously. The MLPs were to host a brigade

Brigade

A brigade is a major tactical military formation that is typically composed of two to five battalions, plus supporting elements depending on the era and nationality of a given army and could be perceived as an enlarged/reinforced regiment...

-size force, sail at 20 knots (10.9 m/s), and have a maximum range of 9000 nautical miles (16,668 km). Each ship was to cost US$1.5 billion to build. However, cutbacks to defense spending planned for the Fiscal Year 2011 budget forced the downscaling of the design in mid 2009.

General Dynamics identified the civilian (built by the subsidiary National Steel and Shipbuilding Company

National Steel and Shipbuilding Company

National Steel and Shipbuilding Company, commonly referred to as NASSCO, is a shipyard in San Diego, California and Norfolk, Virginia and a division of General Dynamics. The shipyard specializes in constructing commercial cargo ships and auxiliary vessels for the US Navy and Military Sealift...

) as a suitable basis for an "MLP 'Lite'", with the design modified into a float-on/float-off vessel that could be built for only US$500 million per ship. As part of the cost tradeoff, the Vehicle Transfer System was scrapped in favour of skin-to-skin mooring of a host ship alongside the MLP, and the LCAC complement was reduced to three. The new design is 837 feet (255.1 m) long, with a beam

Beam (nautical)

The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...

 of 164 feet (50 m), a top speed of 15 knots (8.2 m/s), and a maximum range of 9500 nautical miles (17,594 km).

Concept testing

In September 2005, the United States Navy approved trials of the MLP concept, to test the feasibility of seabasing

Seabasing

Seabasing is a naval capability that provides commanders with the ability to conduct selected functions and tasks at sea without reliance on infrastructure ashore. It describes the concepts and methods for sustaining large military forces during operations at large distances from traditional...

 for an amphibious operation

Amphibious warfare

Amphibious warfare is the use of naval firepower, logistics and strategy to project military power ashore. In previous eras it stood as the primary method of delivering troops to non-contiguous enemy-held terrain...

. The heavy lift ship

Heavy lift ship

A heavy lift ship is a vessel designed to move very large loads that cannot be handled by normally equipped ships. They are of two types: semi-submerging capable of lifting another ship out of the water and transporting it; and vessels that augment unloading facilities at inadequately equipped...

 MV Mighty Servant 1

Mighty Servant 1

Mighty Servant 1 is a 29,000-ton heavy-lift ship capable of carrying very large vessels and offshore platforms. built for Dutch shipping firm Wijsmuller Transport, which merged in 1993 with Dock Express Shipping to become Breda-based offshore heavy lifting group, Dockwise Shipping B.V...

 served as the substitute for the MLP, while the Roll-on/roll-off vessel played the role of a planned type of transport ship for the United States Maritime Prepositioning Force. The first part of the trial consisted of the two ships transferring cargo between themselves while anchored in Puget Sound

Puget Sound

Puget Sound is a sound in the U.S. state of Washington. It is a complex estuarine system of interconnected marine waterways and basins, with one major and one minor connection to the Strait of Juan de Fuca and the Pacific Ocean — Admiralty Inlet being the major connection and...

. After successfully completing this, the vessels sailed to San Diego, where cargo was transferred from Watkins to Mighty Servant 1, then taken ashore by LCACs; slightly submerging the deck of the heavy lift ship allowed the hovercraft to "'fly' aboard".

A second series of tests was conducted off Norfolk, Virginia

Norfolk, Virginia

Norfolk is an independent city in the Commonwealth of Virginia in the United States. With a population of 242,803 as of the 2010 Census, it is Virginia's second-largest city behind neighboring Virginia Beach....

 in September and October 2006, with and MV Mighty Servant 3. This time, the ships were moored together while underway, during which vehicles drove from Red Cloud onto Mighty Servant 3, then embarked aboard LCACs. In February 2010, Mighty Servant 3 joined for further trials in the Gulf of Mexico. During these, personnel and a wide range of vehicles, from Humvees to M1 Abrams

M1 Abrams

The M1 Abrams is a third-generation main battle tank produced in the United States. It is named after General Creighton Abrams, former Army Chief of Staff and Commander of US military forces in Vietnam from 1968 to 1972. The M1 is a well armed, heavily armored, and highly mobile tank designed for...

 tanks, were transferred to, then launched from Mighty Servant 3, in conditions up to Sea State

Sea state

In oceanography, a sea state is the general condition of the free surface on a large body of water—with respect to wind waves and swell—at a certain location and moment. A sea state is characterized by statistics, including the wave height, period, and power spectrum. The sea state varies with...

 4.

Construction

In August 2010, the National Steel and Shipbuilding Company in San Diego was awarded a US$115 million contract to design the Mobile Landing Platform, and build the first ship. Construction on the first vessel began in July 2011.

The propulsion motors are of British design and build. Power conversion company Converteam

Converteam

Converteam was an electrical engineering company based in France, and a former division of Alstom. It is now part of General Electric-History:...

was selected as the supplier of Integrated Power Systems with the award of an additional contract to design and supply the electric power, propulsion and vessel automation system for the MLP.

Orders for the second and third vessels are expected to be made in the 2013 and 2015 fiscal years. The first ship is to be operational by 2015, with the third in service by 2018.