Knew a guy like that in the Navy (what he was doing in the Navy, I have no idea). The instant they announced, "Shift Colors, Underway", he would start getting sick (not that you get sick mind you). But this dude would go green. Like "Kermit the Frog" Green. Followed by his head in a trash can for the next day or so until the dramamine kicked in. Then he was so-so. Luckily, he wasn't in my division so I could make tracks out of the compartment and go somewhere else. They ended up cutting him loose. Bummer. He was a good guy.
Fear of capsizing? Good fear. I think everyone has a variety of that one. Especially the snipes. Down in the engine room when something goes bang and your world turns upside down followed by flooding. Yeah, that's a good one.
We oughta start a thread on viable but irrational fears.