USNS John Glenn (T-ESD-2), (formerly MLP-2)[3] is a United States Navy Expeditionary Transfer Dock ship.
The Expeditionary Transfer Dock is a new concept, part of the Maritime Prepositioning Force of the future. To control costs, the ships will not be built to combat vessel standards and are designed primarily to support three military hovercraft (such as the Landing Craft Air Cushion (LCAC)), vehicle staging with a sideport ramp and large mooring fenders. A decision was made to eliminate helicopter capability and ship-to-ship transfer of heavy equipment.[2]

The propulsion motors are of British design and build. Power conversion company Converteam 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.[5]

As an auxiliary support ship, her role would be a seagoing pier for friendly forces in case accessibility to onshore bases is denied. Such flexibility would be useful following natural disasters and for supporting US Marines once they are ashore.[2][4]
https://en.wikipedia.org/wiki/USNS_Jo...