The boats tested were Zodiac’s Hurricane 733 outboard, of which the Canadian Coast Guard owns about 100 (they call them RHIBs) that are often used for rescue in poor weather.

But an engineer with Zodiac Hurricane Technologies Inc noted the study required operators to sit firmly in their seats, contrary to Zodiac's advice to customers and to the coast guard's own instructions to its sailors.

"The scientific validity of the study that the coast guard did on the boats is questionable because the configuration that they tested is not the configuration that people actually use when they're driving the boats," John Garfitt said in an interview from Delta, B.C. "In fact, they should not keep their bums firmly planted in their seats because that will result in back injuries - and it's just common sense."

The coast guard ordered the study after one of its West Coast sailors won a workers' compensation claim for hip problems he alleged were aggravated by the pounding of an RHIB.

The $85,000 Weir report, intended to provide baseline data only, also urged further experiments to determine whether specially designed seats and deck mats could help to significantly reduce vibrations - though Garfitt warned there can be pitfalls.