Back Injuries Caused By Boats-Study Finds

I laughed when I seen this.
$85,000 spent to confirm what people who go to sea already know!!
In this case it is the rigid hull inflatables.
But, when I was sailing, just about every engineer I knew had back, hip, and knee pain. How many of us have been thrown across a space in bad weather, when you are caught off balance in a bad roll or pitch?

Bouncing boats cause back pain studyBy DEAN BEEBY The Canadian Press
OTTAWA — An $85,000 study for the Canadian Coast Guard has confirmed what many sailors already know: bouncing around heavy seas in a Zodiac boat is hard on the back.
The study was ordered a year ago after a sailor on the West Coast won a workers’ compensation claim for hip problems he claimed were aggravated by the pounding of a Zodiac.
Medical experts at the compensation hearings were forced to support the claim by citing studies on injuries to Ukrainian farmers from tractors, since there was no research on boats.
But a study by Weir Canada Inc., delivered in July, has now demonstrated scientifically that Zodiacs can be like jackhammers in rough water.
The coast guard owns about 900 of the so-called rigid hull inflatable boats, known as RHIBs, often used for search-and-rescue.
Weir Canada measured the assault on the bodies of volunteers when one model — the Zodiac Hurricane 733 outboard — plowed through a range of sea states.
Up-and-down vibrations were the most intense on the 7.3-metre craft, compared with side-to-side. And the Zodiac’s standard seats actually amplified the effect, says the study, obtained under the Access to Information Act.
Researchers also determined that vibration levels were generally at or even higher than limits set under an international standard for the drivers of land vehicles, such as trucks.
"These results suggest the need for mitigation," the study concluded.
The coast guard already instructs its operators to stand up rather than sit when navigating at higher speeds in rough water, in order to minimize vibrations — a measure the study says is effective.
But the report also calls for more research into shock-absorbing seats, into soft deck material and into more realistic conditions rather than the tightly controlled experiments conducted by the researchers.
"People, following a long boat ride, they have back pain," coast guard official Yves Villemaire said at the time the study was ordered.
"And people are saying if we feel this bad, maybe there’s a longterm health effect."
The shock impact of RHIBs in high seas has been measured at up to 11 Gs, or 11 times the force of gravity.
The coast guard has not yet decided whether to carry out further research, but will consult with other countries that use RHIBs about establishing standards, a spokesman said.
"Our next step as the coast guard is to begin more extensive discussions with our colleagues in the same business, operating the same kind of boats, both here in North America and in other places, to look at whether or not new standards have to be developed," said Dave Faulkner, director general of integrated technical services.
Faulkner said that there have been no known injuries reported since the West Coast workers’ compensation case.