Unfortunately, it doesn't work in my case. I seem to have a peculiar affliction for a certain type of motion that only occurs on the ocean, or a body of water connected to it, such as a large bay. I'm not sure what it is, but I think it has something to do with the ocean's swells - the heaving motion.
As long as a boat is moving fast, 12+ knots or so, I don't experience any motion sickness, regardless of wave height. When the boat slows, or stops I get sick.
I'm a pilot and have no issues with motion sickness while flying, even if performing maneuvers that would make most queasy. Stick me in or on a body of saltwater (freshwater lakes don't bother me) and I get nauseous every single time. I have tried to overcome it dozens of times, but nothing has worked so far.
I think when my ancestors came to America, many centuries ago, the trip must have been so horrible, the memory of that experience somehow embedded itself into my genes! lol
Have you tried the Scopolamine patch? My husband can get seasick from time to time if it’s rough, as well, and they work great for him. We were on a five day/four night nonstop sail from Puerto Rico to the Turks and Caicos many years ago with another couple helping them deliver their sailboat to Florida from Tortolla, BVI. The wife got so seasick that she was dead to the world. I put a patch on her (behind the ear) and within 15 minutes she was a new woman! Usually, you apply them before setting sail but she was not having a problem until the second or third day of rolling seas, four hour watches, hand steering because the autopilot was broken and staring at the wonky compass to hold course hundreds of miles from land. I can get a little queasy myself if the conditions are really bad, but I usually get over it with not much of a problem - it’s not fun, I know. I think you can still get the patches by prescription, though you can buy them over the counter in the BVIs, Turks and Caicos and, I think, the Bahamas.