Gulags. Possibly to something more like Andersonville or the "Old Jersey"
The ship's name would probably be Hornet, Forrestal, Intrepid, Lexington,or Midway
Pressed into "other duties" from their current roles as museums. There are other such ships available in the mothball fleet, and others from the active fleet (both big carriers and amphibious assault ships) could be pressed into "Gulag Ship" duties.) These include Kennedy, Ranger, Constellation, Independence, plus Saipan, Shreveport, Austin. Plus a bunch of LKAs (amphibious cargo ship) and LSTs (landing ship tank).