Contrary to much popular opinion, many sailors and other professional seafarers suffer, to greater or lesser degrees, from seasickness when they re-embark on sea voyages. Suffering dizziness, tiredness, general discomfort, and, at the worst, nausea and vomiting, undermines their ability to fulfil their duties, at least during the early stage of their mission. Effectively countering, indeed preventing, seasickness would benefit both the individuals concerned and the efficiency with which they execute their duties.

“Existing models tend to describe levels of motion sickness for groups, rather than individuals,” points out Stellenbosch University Mechanical and Mechantronic Engineering Department postdoctoral research fellow Dr Nicole Taylor. “Studies on motion sickness appear to be conducted in a manner that collects data from individuals, then aggregate results during analysis.”

But the response of people to the three-dimensional motion of a ship at sea is highly individual. Some are immune to seasickness; and those who are not, experience the affliction on a scale that runs from mild to severe. Further, their responses to it also differ. There is thus a need to gather and process data on seasickness at an individual level. And that is what Taylor has done, with a study of seasickness among the crew and passengers onboard South Africa’s Antarctic research ship, the SA Agulhas II.

She was able to gather the individual data for her study, by creating, herself and in-house, an app she calls Mariner 4.0, which she manually installed on the smartphones of those personnel onboard the ship who had agreed to participate in her study. Mariner 4.0 is user-friendly, with a usability score of 84%, and the SA Agulhas II has its own onboard vessel-wide Internet data network, with Wi-Fi access.

“With the Mariner 4.0 system, data on motion sickness and occupant location, as well as ship motion that typically make passengers sick in parallel, can be measured and analysed quickly,” she notes. “It also provides accurate estimates of how sick passengers feel based on how much the ship moves.”

The research participants used the app to log their seasickness experiences, and where on the ship they had them, at least three times each day (those three times were the daily mealtimes). In addition, they filled in paper questionnaires, every day, covering their experiences over the previous 24 hours.

“Personalised [seasickness] thresholds for multiple seafarers were generated that can help diagnose whether individuals may be motion sick or what percentage of seafarers in a cohort may have motion sickness symptoms when exposed to a certain level of ship motion over specific durations,” she reports. “These thresholds can be tailored to voyage specifications, and different voyage missions, including duration of motion exposure, and can be used on voyages that are longer than six hours (a previous restriction for the assessment of motion sickness). Thresholds such as these were not reported in literature prior to my doctoral study.”

Taylor is a mechatronic engineer. She is a postdoctoral research fellow in the University’s Sound and Vibration and Mechatronics, Automation and Design Research Groups.