found the following article recently. It deals with surboard
construction, but it's applicable to windsurfers too. Might
be of interest to board manufacturers, but I don't have time
to track down their email addresses. Enjoy...
Tuesday, January 24, 2006
Surfing On Advanced Composites
Jan 24 2006 1:16PM | Permalink | Email this | Comments (0) |
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Surfboard manufacturing may conjure up images of a guy in board shorts
and a respirator hand crafting boards in a California garage. In
reality, though, surfboards have gone high tech. Consider, for example,
a radical new board design from Hydro Epic Inc.
The company creates its patented surfboard from advanced
composites--laminates of aluminum honeycomb, epoxy, and various
combinations of Kevlar, carbon fibers and glass. It's a surfboard
that would appeal as much to aerospace engineers as surfers.
Boat designers would find its design familiar too. Hydro Epic's
founders, Peter Mehiel and Mark Itnyre, both sailors, took some cues
from sailboat design and made their surfboard hollow like the hull of a
ship. "The composites are just a shell,"says Mehiel. "There's
about two to three inches of air space inside the board."
The hollow Hydro Epic board couldn't be more different than most
modern surfboards. For the past few decades, just about all surfboards
have been constructed from a solid polyurethane foam core stiffened by
a wood stringer and encapsulated by fiberglass. And while there have
been plenty of innovations related to board design, they have been
incremental ones. "Board shapers reached a plateau in terms of what
they could do with foam," explains Mehiel. "The foams used in
surfboards just won't allow drastic reductions in weight or
improvements in strength or stiffness."
The same can't be said for composites. Mehiel, a chemical engineer,
says Hydro Epic boards, with their hollow, air-filled centers, weigh 15
to 50 percent less than a foam core board. "We could make our boards
even lighter, but surfers like to feel some mass under their feet as
they drop down the face of a wave," he says.
More important than the weight, however, was creating a board that
"surfs better." Mehiel acknowleges that this can be a slippery
concept, since it relies on the subjective feedback from surfers riding
under constantly changing conditions. "Every wave is different, so
it's impossible to duplicate conditions the way you would in a
lab," Mehiel says.
Still, he make a strong technical case for why composite boards can
offer a performance edge. It all comes down to controlling stiffness.
Hydro Epic uses composites engineering methods--including materials
selection, fiber orientation, and rib placement--to make the boards
more flexible in their long axis.According to Mehiel, the boards offer
about 15 to 30 percent more flexibility than a comparable
foam-and-fiberglass board.In Mehiel's view, the extra flexibility,
without breaking, helps keeps more of the board in contact with the
wave at any given time, "which results in more efficient energy
transfer between board and wave."
At the same time, Hydro Epic engineers its boards to have about ten
percent more torsional stiffness than a foam board. Mehiel believes
that the extra torsional stiffness, which he hasn't yet quantified,
helps keep the board's rails in better contact with water when the
surfer carves turns in the face of the wave.
Composites have other advantages too. Mehiel notes that epoxy
composites have good tensile and fatigue strength, and they resist
chemicals and salt water. So the boards hold up to lots of abuse.
What's more, he says, the two-step molding and bonding process
inherently offers more manufacturing efficiency than the multi-step,
multi-supplier process used for foam-and-fiberglass boards.
The one downside to the use of composites has been price. Hydro Epic
sells boards for $800 to $1,250, while conventional boards usually cost
between $500 and $900. But a couple of factors do weigh in Hydro
Epic's favor. Strength is one. "Aggressive surfers might break two
or three boards a year," Mehiel says.
And then there's a foam supply disruption that has put the surfboard
industry in a panic. Clark Foam, which by most accounts supplied
upwards of 90 percent of foam blanks used by North American surfboard
makers, unexpectedly closed its doors late last year, citing pressure
related to environmental regulations. Prices for finished surfboards
shot up almost overnight. Mehiel says he's prices rise by as much as
$150 on a $500 boards. "I think the time is right for composites,"