Expeditionary Transfer Dock
An Expeditionary Transfer Dock (ESD), formerly the Mobile Landing Platform (MLP), is designed to be a semi-submersible, flexible, modular platform providing the US Navy with the capability to perform large-scale logistics movements such as the transfer of vehicles and equipment from sea to shore. These ships significantly reduce the dependency on foreign ports and provide support in the absence of port availability.
Source: Wikipedia — Expeditionary Transfer Dock (CC BY-SA 4.0)