Sailors tend to live on myth, but there is science to seasickness and other motion sickness. The frequency of the motion counts.
Scientists have known for a long time that a certain frequency of motion induces motion sickness faster and more reliably, in fact at the right frequency most people will succumb and be feeling at least unwell.
That frequency is 0.2Hz or a cyclic motion that completes once every 5 seconds. Its a long slow wallowing type of motion.
Monohulls BTW, do this quite easily, but Catamarans tend to have a higher frequency “Jerky” sort of motion. Probably explains why some people don’t get sick on catamarans.
Especially in rough seas, Monohulls have a nicer softer motion that tends to roll through waves a little more than a catamaran, which tends to crash through them and jerkily move up down and sideways.