No! you will not get seasick. Not even on the original full motion water mattress... For example, some customers can get sea sick, car sick and motion sickness, but never on their Waterbed mattress.
The Waterbed's gentle motion quickly subsides and the total support provided leads to relaxed, sound sleep. Tossing and turning is greatly reduced because the Waterbed's even support creates no pressure points to disturb the sleeper.
The mattress only moves when you do.