Not sure if they post the schedule anywhere, but you'd likely have to call them to find out. Not sure either how often they rotate, but when I was on the Freedom back in October of 2010, it was Graham Seymour.
2007 - Majesty of the Seas (Bahamas)
2009 - Enchantment of the Seas (Western Caribbean)
2010 - Freedom of the Seas (Western Caribbean)
2013 - Golden Princess (Alaska, roundtrip from Seattle)