The USN is getting ready to launch the USNS Lewis Puller, a new class of forward bases afloat. It's an interesting design, starting life as a tanker, and then it got a massive flight deck added to the top. Instead of enclosing the area beneath the flight deck it's left the area open on purpose so it can handle ovesized cargo and even deploy small boats. It's ugly as hell, but for the job it's very well suited. It's mission is going to be acting as a forward base-afloat, so other units can retrieve supplies and such. The primary difference with other sealift command supply vessels is that this one is only a boat to get from point A to point B. It's a logistical spider in the middle of it's supply web. It will certainly make it easier to deploy forces further forward where land bases aren't always available.
http://www.thedrive.com/the-war-zone/12402/the-navys-gargantuan-new-sea-base-is-on-its-way-to-the-middle-east
http://www.thedrive.com/the-war-zone/12402/the-navys-gargantuan-new-sea-base-is-on-its-way-to-the-middle-east