I get badly motionsick on boats that are bobbing more than a little bit. I don’t seem to get motionsick on planes, though. Possibly I’m just used to planes. Since I’ve been on a boat all of three times in my life that I can remember, maybe I’m just not used to it.
Also, I went skydiving two weekends ago, and got motionsick - AFTER the parachute popped. The jump out of the plane was fine, and the free-fall felt great - no problems at all. But as soon as the chute deployed and we were gliding, I got the urge to puke. The parachute instructor I was clipped to (tandem jump) said to look at the horizon. This helped a little bit; I still felt quite queasy, but the urge to actually vomit went down some. It’s as if my brain kept hearing the “whoah, we’re swinging back and fourth and feeling really weird here” messages from my inner ear, but had an easier time ignoring them because of the visual reinforcement.
I say this all as background to the following…
I have a theory as to why some people get motionsick and some don’t. And I think it nicely accounts for my experience. I came up with it while pondering why some people get motion-sick playing certain video games. Doom, Quake, or Descent in particular. I never do, but I know people who get very dizzy from them. Descent seems particularly bad because there is really no obvious “up”
in the game - you are in a weightless environment and you may position your ship (and thus your viewpoint) in any orientation relative to the tunnels you are navigating through with no positive or negative effects. Usually, people end up just randomly picking one wall as treating it as the “floor” until it becomes inconvenient to do so. Then they switch their definition of “floor.”
Anyway, my theory. Basically, I think everyone gets a certain amount of their sense of balance from their eyes (looking at the horizon or stationary objects) and a certain amount from their inner ear. Those of us who get more of it from the inner ear can play video games with confusing visual orientation, no problem. Our brain listens more to our inner ear, which is telling it, “You’re sitting straight up ans stationary in a chair, playing a video game.” But, the downside is that if we’re in a situation where we’re moving around a lot in an irregular way (paragliding, small boat in rough seas, car twisting through the mountains), even if there’s a good visual orientation, our brain still feels mostly like we’re unbalanced due to the inner ear dominating our sense of balance. People who balance more visually have the opposite problem - even sitting still, if their visual orientation changes suddenly, they get dizzy.
I’m sorry, I know this doen’t help with your dilemma. And I too an skeptical of those bracelets that claim to cure motion sickness. I suspect their effect is mostly psychological. (Which is fine, actually. If you don’t think you’re dizzy or motionsick, maybe you aren’t. Or you won’t notice it nearly as much. Placebo effect is real, and as a famous signature line goes, some effect is much better than no effect at all.)
The only solace I can give you is that I’ve read that when brand new sailors go onboard a ship, it usually takes them about two weeks of puking before they “get their sea legs.” This doesn’t help you, of course. You’re just starting to get used to it right as the cruise ends. I guess you could try spending a fair amount of time on some fishing boats in the two weeks prior to the cruise to try and pre-acclimate your brain?
-Ben