That is basically what I was on - an amphibious assault ship, an LST - no keel, flat bottom, would roll side-to-side in the calmest of seas. I only came close to getting seasick once. We were at GQ and I was stationed in the radar room. It was hot because the air handlers were shut down (modified condition Zebra), I was wearing a Mark V gas mask and sitting on the very s;lick plastic floor electrically insulating covering and was sliding back and forth while having to speak/listen to the sound powered phone checking in every few minutes.
