Scientists target ships’ rock ’n’ roll

Navy Sailors will be happy about this!!!

Unwanted vessel motion causes more problems than seasickness
By CHRIS LAMBIE Staff Reporter

Seasick sailors rejoice. Defence scientists are looking for a way to reduce the amount warships roll by half. "One of the aims is to increase crew comfort because ship motions have several effects on humans," said Kevin McTaggart, an engineer with Defence Research and Development Canada. "The one that a lot of people are familiar with is seasickness, which, of course, is a problem for people, including our sailors in the navy."

Queasy crewmen can experience difficulties doing simple things like using computer keyboards.
"You get nauseous and you have trouble concentrating," Mr. McTaggart asid.
When a ship rolls excessively, crewmembers can stumble and fall, causing injuries, he said.
"The other thing that ship motions cause is physical fatigue. One of the problems with physical fatigue is that it tends to accumulate with time."

When a vessel rolls a lot, sailors are constantly using their muscles to keep themselves upright.
"And the other aspect is that, if the ship motions are quite large, then you have trouble sleeping at night."
Besides making life more comfortable for sailors, the technology could allow warships to complete dangerous tasks in much rougher seas than they can now.
"It might extend the sea conditions under which you could do helicopter operations or replenishments at sea," Mr. McTaggart said.
He’s planning a $90,000 feasibility study that will examine several different possible methods to reduce rolling.
"One of the things used quite a bit by the U.S. navy, in particular, is rudder-roll stabilization," he said.
"They monitor the ship motions and then they use a fairly sophisticated control system to drive the rudder, so that it’s not only steering the ship, but also reducing the roll motions at the same time."
Another possibility is stabilizer fins mounted in the middle of ships at an angle. Like the rudder systems, they move automatically to make ships sail more smoothly.
"We think there’s potential for reducing the roll motions by up to 50 per cent," Mr. McTaggart said.
Before people put away the seasickness pills altogether, he cautioned that nothing will reduce pitching or heaving motions in the navy’s frigates and destroyers.
But it might help lessen the corkscrewing combination of pitching and rolling that drives many to the leeward rail to lose their lunch.
The roll-reduction technology could be applied to any new warships the navy buys, he said.
"It’s also applicable to refits of existing ships. It’s the sort of thing that you might consider during a mid-life refit."
There’s a possibility, he said, that the roll-reduction systems could be installed in Canada’s 12 Halifax-class frigates during their $3.1-billion mid-life refit expected to take place between 2010 and 2017.
"Generally, smaller ships roll more than larger ships," Mr. McTaggart said. "But even on larger vessels of 4,000 to 8,000 tonnes, the roll motions can be certainly very noticeable and can impact on operations."
Besides the Americans, the British navy is using roll-reducing technology in its warships. Some civilian vessels also employ similar devices to seemingly reduce the motion of the ocean.
The feasibility study will examine how noisy and robust any roll-reducing system might be, as well as how vulnerable it would be to shock and ice.
It will also look at how much the anti-rolling systems cost.
"For a rough order of magnitude, I would say it would be a fraction of one per cent of the total ship cost," Mr. McTaggart said.

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