My vote goes to Stugeron too. The trick with this stuff is to take it before your journey starts. If you get to the point where you FEEL you need something, then it is too late.
With Stugeron, I take two at least one hour before sailing, and then 1 every 4 hours for the first day or two, whilst awake. Dropping to 1 when waking in the morning thereafter.
I only need it whilst cruising or sailing for several days, as that requires going below whilst on the move. Day sailing and short course racing, I don't need them at all.