I commented on this in a different thread and then decided I'd start a new thread. I'm sure we have lots of people on the forum that have significant experience cruising. I'm interesting in peoples opinions/experiences from various cruise/tours they've taken with respect to the sea-state they encountered and if any fellow travelers experienced sea-sickness.
I've taken the Tauck small ship (Ponant) Venice and Dalmatian Coast tour. On that tour no one that I know of had any sea-sickness. You could barely even tell you were on a ship the seas were so calm. Another Tauck tour was the Treasures of the Aegean on the Windstar. Again, there were no cases of sea-sickness and the seas were very calm.
A non-Tauck tour that I took of the UK and Ireland took a ferry from Wales to Dublin. During the crossing it seemed like the deck of the ship was at about a 30 degree tilt. It made walking on the deck interesting, but I heard of no sea-sickness cases.
A non-Tauck tour I took in Australia had an excursion from Cairns to the Great Barrier Reef. On that transit some people did experience sea-sickness and had to make deposits in the sea-sickness bags. When I see someone doing that it promotes a gag reflex, so I have to immediately head to other parts of the boat or I would be joining the bag depositors.
I would suspect that of the Tauck tours Antarctica, followed by any tours that cross the Arctic Circle would have the highest possibility for unpleasant sea-states.
I'd love to hear experienced cruisers (especially on the small Ponant like ships) tales relative to sea-state. I don't know but I'd think the large cruise ships (thousands of passengers) could drive through most anything short of a hurricane without creating a large sea-sickness issue.