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 Post subject: Good Helmet Article From An Expert
PostPosted: Wed Mar 02, 2005 5:49 pm 
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I just came across an article about kayak helmet with content from Prof. David Halstead of the University of Tennessee, Director of the Sports Biomechanics Impact Laboratory and a research scientist for the school's Institute for Injury and Trauma Prevention. I have been talking to David on and off for years about helmets for kiteboarding. (reposted after original article corrupted, sigh).

IF YOU ARE LOOKING AROUND FOR A KITEBOARDING HELMET - READ THIS CAREFULLY


"Between a Rock and a Soft Place
Choosing the safest helmet
Tom Price
When his son Lucas died kayaking the North Fork of the Payette in July 1998, Gil Turner wanted to know why. Luke was a world-class boater (his younger brother Nick paddles for TGR), and knew what he was doing. When Gil learned that it was Luke’s helmet that failed, not his skills, he launched what has become his life’s mission: exposing the little secret of the paddling industry, namely that there are no U.S. safety standards for kayak helmets. He founded the Whitewater Safety and Research Institute to push adoption of a new set of standards by the American Society of Testing Materials (ASTM), which are now being developed.

What should you look for if you want to be safe on the river? We suggest putting aside your preconceptions, and reading the following unbiased look at what’s out there. It may make the difference between a paddle on the river, and a ride in an ambulance.

First, some basic information. A day on a river is likely to include some inverted time. Your helmet is a product with as many designs as there are rivers, with no two models alike. Generally, helmets fall into three categories: lightweight models, designed first and foremost to be comfortable; a middle group, that absorbs the impact of small to large bumps; and the beefy models that will let you feel most knocks, but will save you from a blow that could knock you out.

While there is a European standard, called CE, that most companies adhere to, almost all agree it’s inadequate. There’s a warning label on most helmets saying that the helmet is designed "so the energy of an impact is absorbed through partial destruction, which may not be visible to the naked eye." Most of these labels also include the advice that, after a helmet experiences this "partial destruction," it should then be destroyed or returned—though the labels don’t say how you are supposed to identify this invisible destruction. Obviously, a whitewater helmet is likely to get hundreds of impacts. But without a uniform U.S. standard, who knows what to look for?

If anyone, it’s Prof. David Halstead of the University of Tennessee, Director of the Sports Biomechanics Impact Laboratory and a research scientist for the school's Institute for Injury and Trauma Prevention. "The typical performance of helmets you can buy is poor when it comes to protecting your head," he says, adding that there are exceptions. While many manufacturers emphasize comfort, Halstead believes comfort should be sacrificed on the altar of impact management. "A helmet should stay securely in place, and disperse the impact of a blow throughout the helmet," he maintains. He looks at three helmet characteristics: outer shell, liner, and fitting system.

Shells: There are two basic kinds of shells—plastic and composite. Plastic comes in three common forms: polyethylene, "which is not as resistant to impact and penetration;" polycarbonate, "which can have impressive properties," or polyurethane, which comes in so many forms "it’s like calling it dirt. Is it loam, clay, topsoil or sand?" Without getting too technical, Halstead believes plastic shells require even greater attention to the liner. "If you pick up a helmet and the plastic looks like a kids toy, and it’s relatively flexible and has an interior component foam you can squish down to the shell, that’s not going to protect you." Plastic does have one benefit, it allows for drain holes, which prevent "bucketing," helping to keep the helmet in place. Conversely, holes reduce protection, so a closer fitting full helmet would seem to offer more overall protection.

Halstead prefers composite shells for their ability to spread impacts, but notes that without standards "one strand of carbon fiber and Kevlar is enough to say it’s a composite helmet." He also doesn’t think much of the trend toward fixed brims, saying, "that’s not a bumper, it’s a rudder," noting the brim could scoop water and force the helmet backwards, exposing your forehead. For sun protection, he advocates a snap on, breakaway bill.

Liner: There are three main types of insulation. Expanded Poly-Propylene (EPP) is the most common. It’s very stiff, not affected by moisture, and will take multiple impacts, according to Halstead. Expanded Poly-Styrene is "the very best" energy attenuating substance. It’s what’s used in bike helmets, but generally is only expected to be hit once, and with one exception noted below isn’t used in whitewater helmets. Finally, there are closed-cell foams. The best of these are otherwise known as Vinyl Nitrile, which is a PVC synthetic rubber, heavier in a safe density than EPS/EPP, and will absorb water, but it is usually much softer. A closed-cell foam will also absorb sweat along with water, which can make for a ‘funky’ brain bucket. A fourth insulation, Ethyl Vinyl Acetate or EVA, "isn’t a functional energy attenuator because it’s so springy," says Halstead.

Halstead says stiffer is better. "When you look at the stuff that will actually protect your head, it ought to be so stiff that you think, ‘my God, this is going to hurt.’ But you need that much stiffness to spread the impact. If you pick up a helmet with soft foam inside, the chance of it protecting you is slim." Of course, not everyone agrees with Halstead. Jay Norfleet from Grateful Heads thinks EPP is not a multiple-impact foam because it compresses. And Doug Poe of Pro-Tec believes EVA gives the same protection as closed-cell foam.

Fitting System: "If you take a helmet that has a rigid shell, and a rigid foam, how are you going to make it fit?" asks Halstead. The answer is via the straps and the sizing of the helmet. This is where Lucas Turner’s helmet failed. Once ejected from his kayak, the force of the river caught his helmet long enough to force it back on his forehead, long enough for the fatal blow.

The good news here is that almost all helmets now have two straps on either side, meeting at a single point under the chin (exceptions are noted below). Beyond the straps, look for how many sizes the helmet comes in—the more the better.

Whatever combination of protection you choose, you should follow the "forewarned is forearmed" strategy. It’s worth repeating that until the new standard is released sometime next year, your decision will be dictated by the kind of boater you are, so let your boating conditions determine what helmet you choose.

Helmets

Boeri’s Mojo
Shell: polycarbonate plastic
Liner: EPS, with foam fittings
Fitting system: three point straps that, unique among those we tested, have their rear attachment point at the back of the helmet. Comes in five sizes.
Cost: $70
Comments: New to the scene this summer, being marketed as a combination paddling, skate, and in-line helmet. "If an EPS liner or hard shell is cracked after impact then it did its job and should be replaced, but most impacts are bumps and lacerations thus the "multiple impact" rating." —Robyn Hansen, Marketing Director Boeri USA
Info: 1-800-394-MPH1, www.boeriusa.com

Sport Helmets’ Cascade
Shell: High Density Polyethylene Plastic provides full over ear coverage.
Liner: EPP, with a patented "pump fit" system built in
Cost: $49.95
Fitting system: seven sizes, a single neck strap integrated with back of head "nape" strap.
Comments: With their large range of sizes, over-ear coverage, rear cranial strap and pump fit system, the Cascade may be the Volvo of helmets. "You connect the rear strap and pump it up to fit—I like that idea."—David Halstead
Info: (800)-537-1702, www.sporthelmets.com

Rain and Snow’s Grateful Heads, assorted models
Shell: Kevlar reinforced laminate
Liner: closed mini-cell foam
Fitting system: unique in that all three points per side are adjustable for a much more customized fit. Each model is one size frame, with five thicknesses of foam inside. Not all frames fit every head, 11 frames in all.
Cost: $119.99-$134.99
Comments: "My idea is to create a safe helmet first, and if it looks good that’s a bonus."—Jay Norfleet, President. On the cutting edge of frame shaping, Grateful Heads offers a wide range of styles and fit you won’t find elsewhere—worth a look.
Info: (301) 689-0915, www.gratefulheads.com

Prijon/Wildwasser Sport USA’s Wildwater Competition
Shell: "high-impact" plastic, plenty of drain holes
Liner: closed cell foam, with shim kit for customizing
Fitting system: One size fits all, best for larger heads, plus padding inserts for flat spots. Three point straps per side.
Cost: $59.95
Comments: "For us, safety is first, then fit, then comfort." —Christian Mason, General Manager. The most commonly used helmet on the market.
Info: (303) 444-2336, www.wildnet.com

Harmony/Lidd’s Verve
Shell: Composite Kevlar and fiberglass
Liner: EPP
Fitting system: three sizes, three point straps on either side
Cost: $199.99
Comments: "The slickest and best helmet I’ve seen, but I haven’t seen ‘em all," says Halstead. Carries a lifetime warranty.
Info: (800) 591-2282, www.harmonygear.com

Predator
Shell: ABS plastic (stiffer than polypropylene), plus models in Elite Carbon.
Liner: Closed-cell foam.
Fitting system: two styles, short- and full-cut, with six-point adjustable chin straps.
Cost: $39.95 (fiberglass Rockhead $125; Elite Carbon $140)
Comments: Available in three sizes (s,m,x/xl) and four colors, with six drainage holes. "Plastic helmets haven’t been popular because they're ugly and don't fit well. We've solved all of that."
Info: (604) 858-0645, www.predatorhelmets.com

Protec’s Ace Water
Shell: High-density ABS plastic, lots of drainage
Liner: Expanded EVA foam
Fitting system: Three point straps per side. Note that forward strap is mounted two inches higher than rear, unique among the helmets we looked at.
Cost: $39.95

Comments: "We feel if the helmets are more comfortable and more lightweight, more people will be likely to wear them."—Doug Poe, President and VP of Research and Design.
Info: 800-338-6068, www.pro-tec.net

Shred Ready’s Shaggy
Shell: Kevlar, fiberglass impregnated with vinylester resin with a forward fixed brim
Liner: EPP
Fitting system: Comes in two sizes, three point straps per side.
Cost: $ 95.00
Comments: "We try to handle the small to medium hits so you don’t feel them." —Tom Sherburne, Owner
Info: 334-257-1212, www.shredready.com

FROM: http://www.paddlermagazine.com/issues/2 ... _123.shtml


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 Post subject:
PostPosted: Wed Mar 02, 2005 5:50 pm 
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Kayak helmet development is far ahead compared to kiteboarding helmet evolution. There are very few purpose built and designed kiteboarding helmets in existence today.

The performance environment for kayak helmets overlaps kiteboarding in some areas and yet differs significantly in others. Drag is probably a more significant consideration in kiteboarding than perhaps in kayaking.

Kayakers generally don't hit more or less stationary water at 20 mph+ whereas kiteboarders can do so almost routinely. Kayakers aren't lofted up to 20 ft. above the water to hammer in at high speed against water if something doesn't go quite right.

Any source of drag such as excessive helmet size/diameter and critically fixed projections MAY torque or otherwise injure the riders neck. The rider's head may be rotating at high speed at time of impact further complicating the geometry and forces of the impact against water. That is the part in the front may be in the back and rotating upward or downward at speed at time of impact, etc. Kiteboarders want a smooth, low drag helmet for what may be routine higher speed impacts against water.

Kayakers are concerned about hitting rocks and hard objects at speed as kiteboarders should be as well. Kayak helmets have developed a lot along lines to try to manage these sorts of more severe impacts. Using things like kevlar/composite shells, polystyrene liners secure fastening systems, etc. Kiteboarders can benefit from these features as well.
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