Expeditionary Sea Base (ESB)
Formerly known as Mobile Landing Platform (MLP), the Expeditionary Transfer Dock (ESD) / Expeditionary Sea Base (ESB) is a new class of auxiliary vessels under construction for the US Navy.
In April 2011, the US Navy placed a contract with General Dynamics National Steel and Shipbuilding Company (NASSCO) for the detailed design and construction of two ESD ships.
In May 2011, General Dynamics NASSCO was awarded a $744m modification contract by the US Navy for the construction of the first two ESD vessels.
The US Navy Strategic and Theatre Sealift programme in the Programme Executive Office (PEO), Ships is responsible for the procurement of the ESB ships. The three ESB ships were named USNS Montford Point, USNS John Glenn and USNS Lewis B Puller in January 2012.
The US Navy plans to induct a total of five ESB vessels by 2020. The first two ships are in service with the Maritime Prepositioning Force (MPF) squadrons, while the next three will serve as the Afloat Forward Staging Base (AFSB) vessels.
ESB design features
The ESB concept was tested through a series of at-sea trials by the US Navy. A surrogate ESB ship and roll-on/roll-off vessel were used in exercises to demonstrate the ability in high sea states.
The design of the ESB is based on the Alaska Class tanker. The base design incorporates a core capability set accommodating vehicle scaffolding area, vehicle transfer ramp, skin-to-skin fenders and lanes for three landing craft air cushions (LCACs).
The ESB ship has a length of 239m, beam of 50m and design draft of 12m. The full load displacement of the vessel is 80,000t. Each ESB is manned by a crew of 34 personnel from Military Sealift Command (MSC).
The ESB ships allow the transfer of vehicles and equipment from large medium-speed roll-on/roll-off (LMSR) and joint high-speed vessel (JHSV) to shore through LCACs in Sea State 3 conditions. The mobile landing platforms allow amphibious operations in the absence of ports. The ship is equipped with a mission deck and float-off (FLO/FLO) technology, allowing loading and unloading of the floating cargo.
The ship has storage tanks for 100,000gal of potable water and 590,000gal of JP5 fuel. The mission deck can accept future platform upgrades, including command and control, vehicle transfer system, cranage, accommodation module, medical facilities and a helicopter landing spot.
The 52,000ft² AFSB variant features a flight deck, equipment and fuel storage, berthing and repair spaces, and can accommodate up to 250 personnel.
Construction of ESB
The construction on the first ship in the class, USNS Montford Point (MLP-1), began at the NASSCO shipyard in San Diego, California, in June 2011. The keel was laid for the MLP-1 in January 2012. The final block comprising exhaust stacks was installed in August 2012.
The final structural welds were completed and inspected by the American Bureau of Shipping and the navy. The construction of the first ESD was completed in September 2012. The fabrication process on the second ship began in April 2012. Each ship was installed with core capability set (CCS) modules after delivery from NASSCO.
The USNS Montford Point (MLP-1) was delivered in May 2013. The ship achieved initial operational capability (IOC) in 2015.
The second ship in the class, USNS John Glenn (ESD-2), was launched in September 2013 and completed builder’s sea trials in January 2014. It was delivered to the US Navy in March 2014.
The US Navy placed a detailed design and construction contract for ESB-3, the third ship, in February 2012. The keel for the ESB-3 was laid in November 2013, the christening ceremony was held in February 2015, and the vessel was delivered in June 2015. A request for proposal (RFP) was issued for the CCS for the ESB in March 2012.
NASSCO was awarded a $498m contract by the US Navy for the detailed design and construction of the fourth ESB in December 2014. Construction of the fourth ESB began in October 2015, with completion scheduled for March 2018. Construction of the fifth ESB began in January 2017.
The ESD/ESB ships are powered by twin-screw, diesel-electric propulsion system integrating four MAN/B&W medium-speed diesel engines, 24MW diesel electric plant,and 2MW azimuthing bow thruster. The propulsion system provides a sustained speed of 15k and an endurance of more than 9,500nmi at 15k speed.
In August 2011, Converteam was awarded a contract by General Dynamics NASSCO to supply propulsion, electric power, generators and automation system for the MLP programme.