If you are a seafarer, the last thing you want is to suffer from seasickness (motion sickness). When you are busy with deck and accommodation patrols, steering the vessel, standing on lookout, or assisting the officer on watch, among others, you can do without the dizziness, fatigue, nausea and vomiting and general discomfort.
Because some seafarers are more susceptible to seasickness than others, and their responses differ, it is important to determine how it affects each individual seafarer.
“Existing models tend to describe levels of motion sickness for groups, rather than individuals. Studies on motion sickness appear to be conducted in a manner that collects data from individuals, then aggregate results during analysis,” says Dr Nicole Taylor who is a postdoctoral research fellow in the Sound and Vibration and Mechatronics, Automation and Design Research Groups in the Department of Mechanical and Mechatronic Engineering at Stellenbosch University (SU). Taylor conducted research on motion sickness among passengers and crew on the SA Agulhas II, South Africa’s polar supply and research vessel. She recently obtained her doctorate in Mechatronic Engineering at SU.
As part of her study, Taylor created the Mariner 4.0 system, which equips seafarers with technology that can help them with their tasks, to advance the study of motion sickness among seafarers. The system used the Mariner 4.0 application — a user-friendly mobile app with an 84% usability score that she developed in-house — and paper-based questionnaire booklets, called daily diaries.
Mariner 4.0 facilitated mobile data collection from seafarers on the SA Agulhas II, which is equipped with a myriad of laboratories and instruments for research purposes, including an internet data network with Wi-Fi access points distributed across the vessel to aid communication on board and remotely. The app uses near-field communication technology – wireless technologies that enable communication between devices when they’re placed close together – for location tracking.
Taylor manually installed the Mariner 4.0 app onto participating passengers’ smartphones. They were encouraged to log submissions regarding their experience of motion sickness and location on board through the app at least three times a day during mealtimes; and to complete their daily questionnaires each morning, reflecting on the previous 24 hours when answering their questions. The questionnaires captured feedback from the participants regarding their daily perception and experience of motion sickness (whether they experienced motion sickness, whether they vomited, and how they would assess their motion sickness severity through an illness rating on a scale of 0–3).
Taylor says the Mariner 4.0 system made it possible to monitor the motion sickness of seafarers in almost real-time, which, according to her, is a novel feat in shipping. “With the Mariner 4.0 system, data on motion sickness and occupant location, as well as ship motion that typically make passengers feel sick in parallel, can be measured and analysed quickly. It also provides accurate estimates of how sick passengers feel based on how much the ship moves.
“We were able to collect information directly from the passengers to measure motion sickness by asking them to indicate via the app if they’ve felt sick or not. We could also individually monitor passenger’s exposure to motion for extended durations and measure the severity of motion sickness symptoms.
“Because data is accessible in real time, it is much easier to reduce the incidence and severity of motion sickness symptoms during voyages and to improve the performances of various tasks during ship operations.”
Using motion sickness incidence (whether they displayed motion sickness symptoms or not) and the motion sickness dose value (the portion of motion that occupants are exposed to that will likely induce motion sickness) as measures, Taylor also developed guidelines for assessing motion sickness in passengers, both individually and as a group, and how likely they are to get seasick and how severe it might be. She says they determine specific levels of sickness, or diagnostic thresholds, that indicate whether someone is experiencing motion sickness, considering factors like the purpose of the voyage, the duration of the voyage and how long someone is exposed to ship movements.
“Personalised 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.
“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 adds that these thresholds can also be adapted to various durations of motion exposure from 30 minutes to six hours. They could potentially aid in voyage planning and ship design.
She says future work includes the extension of seakeeping analyses based on weather forecasts to voyage planning stages. “The aim of this is to predict motion sickness incidence on board to support tactical decision making, including weighing up different voyage route suggestions or optimal crew selection.”
Photograph: Dr Nicole Taylor aboard the SA Agulhas II.
Article by Corporate Communication and Marketing/Korporatiewe Kommunikasie en Bemarking [Alec Basson]
