UISS is a tool used by the Littoral Combat Ship, which itself is a new vessel procured by the Navy as a sort of floating jack-of-many-trades. The Littoral Combat Ship is designed to operate close to coasts and in shallower waters that larger naval vessels can't reach (that's the "littoral" part of its name). The LCS is designed to do a variety of tasks that work better closer to shore, like fighting small boats, countering submarines, and defeating underwater mines, and each of those tasks requires a special set of modules. The major problem with the "combat" part of its name ship is that it's armor isn't very good, but for many tasks, it doesn't strictly need to be. And for some of the others, there are helpful robots that will do the job while the LCS is safely out of harm's way.