If it helps, we came back from the isle of man once in a very rough storm.
We were in the car but I gather there had been some sort of cycle festival on the island at the same time and there were lots of cyclist on the ferry back.
Anyway,the ferry was all over the place. The toilets were jam packed full of people throwing up, so much so that when I took my son in for him to be sick, the only free receptical was a sink so he threw up into that and I had to push the bits down the plug hole with my finger. Nice.
When we docked at liverpool, we all went down to the car deck and one of the cars had been merrily rolling around and had smashed into a couple of other cars and a big pile of bikes tied to the bulkhead, it had fecked them over good style. My car was two lines away though and was fine.
HTH.