Don't mean to resurrect a thread this old, but we just got off the Fantasy (June 2 - 9 Cruise in stateroom 7610) and the problem is as bad as ever. But as mentioned, it only seems to happen above 20 knots. The first night we were sailing a peaceful 19.4 knots and there was zero vibration. The second day at sea we had a medical emergency and needed to offload a passenger in Puerto Rico so we sped up to 22 knots and I noticed it as soon as we sped up. I was trying to nap and it was impossible. It went away during our ports of call (weren't in a hurry to get to the next island since they were so close to each other). Then, on the way to Castaway we were at 21.4 knots and it was bad again for the 36 hours we were underway. I asked a few people who I had met on the cruise and they agreed it was pretty annoying. Once I could get to sleep I was fine, but getting to sleep was tough. Like trying to sleep in a motor home with tires out of balance driving down the road
. I had a jeep like this - was smooth as silk until I got above 60 mph and then it was all I could do to keep it on the road. It is the only "negative" I have about this ship or this trip. All in all it was an amazing cruise. Loved every minute of it.