The incidence and prevalence of kinetosis has been investigated in particular in space aviation, among marines and seafarers, as well as in yacht crews taking part in offshore races. On seagoing vessels it is obvious that wind force and sea condition largely contribute to its incidence. About one third of passengers on ferries on average experience motion sickness symptoms of various degrees (3). A ship´s size, its hull shape, the speed and course of movement in relation to the environment (wave direction, length and amplitude, wind direction and force) largely determine the level of motion stress for the individual [4]. People aboard of small vessels are particularly prone to become seasick, since a small craft tends to inflict more motion stress upon its passengers than a large ship in similar weather and sea conditions. Still, a substantial percentage of passengers unaccustomed to the sea may experience motion sickness, even on a tall cruise ship mildly rolling in a moderate Atlantic swell. There also is no absolute resistance to motion sickness, thus even professional and fully habituated crews of large container ships and oil tankers may become seasick in stormy weather and high seas. Experience from very severe sea conditions including reports of life raft passengers indicates that given sufficiently provocative circumstances almost anybody will eventually get seasick [5].



[i]