Defence Department researchers have been trying to make people seasick””but not too seasick””so they can assess their performance under trying conditions.
Faced with shrinking rosters aboard its naval fleet and at the same time demanding more technical expertise from sailors, the military can ill afford to let rough seas compromise operations.
If commanders could identify which crew members are most susceptible to seasickness and under what conditions, they could respond by shortening shifts or replacing vulnerable sailors before they get sick.
Researchers also hope to ultimately identify what tasks can still be done even by those who are seasick, so Defence can decide where to spend its money on replacements.
The problem is, there’s no criteria for measuring seasickness, the precise conditions that cause it, or, particularly, its effect on human performance.
That’s where Jim Colwell and Scott MacKinnon come in.
Colwell, a naval architect with Defence Research and Development Canada, drafted the protocol for a study aimed at controlling illness so researchers can measure how people perform when they’re seasick.
He even came up with a Misery Scale ranging from 0 (no problems), through nine levels of discomfort, nausea, and retching, to 10 (full-scale vomiting).
MacKinnon, an ergonomist, conducted the study in a ship motion simulator at Newfoundland’s Memorial University. His first challenge was finding enough volunteers””20, in the end””willing to get sick for science.
“It’s pretty hard to get people who chronically get motion sickness to actually volunteer to do these types of trials,” said MacKinnon, whose seasick-prone wife, Helen, was among those who signed on.
“We got 20 people who at least demonstrated some levels of motion sickness. Some did end up vomiting. Some dropped out,” he noted. “Typically, it’s very hard to reel them back in once they pass a certain point.”
By altering the simulator’s motions (pitch, roll, yaw, heave, surge, and sway), MacKinnon managed to keep about half the seasick participants in the four-six range, which included sweating, dizziness, and an uneasy stomach, up to slight nausea.
All but two of the others got just seasick enough that the machine’s motions didn’t need to be altered. The two others threw up no matter what the testers did.
The results””that seasickness can be regulated for research purposes””will be published later this summer. The findings also could help industries such as fisheries and commercial shipping.
It’s not the first time motion sickness studies have been conducted, but Colwell said previous projects typically recorded how many people got sick, how fast they got sick, and how sick they got under set conditions.
“The typical kind of experiment is you set the motions at a certain level of severity and then you watch what happens to the people,” he said.
“Generally, people who begin to get motion sick progress through mild, moderate, and fairly severe symptoms over a fairly short period of time.
“So it’s really difficult to look at performance with mild motion sickness when people don’t stabilize at that level but get worse pretty rapidly.”
Colwell and MacKinnon’s study was the first to regulate the motions of the simulator by the seasickness they caused. It required participants to perform rudimentary computer tasks such as math problems and other questions.
“I wondered why anyone who knows how bad it can be would volunteer to put themselves through it,” said study participant Helen MacKinnon.
“Near the end, you got the feeling you just didn’t care, you just wanted to answer the questions. You just weren’t feeling up to it.
“I can see how anybody working on a boat would find it hard to concentrate on their job.”
In fact, the issue came to the fore after a 1997 NATO exercise where about half of 1,025 sailors surveyed aboard seven ships reported varying degrees of seasickness resulting in problems doing their jobs.