The battle of balance
by: Marc Lefebvre
When designing a board there are design features that are in constant battle
and must be balanced to make a good design. Balancing these contradictory
features are what a board designer faces on a daily basis. It is important to
note however that balance does not mean equal. The balance you achieve is
based on what kind of design you are going for. For example a wave board has
vastly different goals than a slalom race board. A wave boards design
goals are looseness, turnability, and durability; a slalom race boards
design goals are top end speed, control at high speeds, and upwind ability; a
recreational slaloms design goals are early planing, easy turning, and control.
Some of the design parameters you fight with are "vee", "tuck", "outline
curve", "wetted surface area", and "rocker", forget volume at the moment.
Vee causes the water to stick to the board more and when taken to the extreme
can make a board hard to plane, but at the right amount will help with control
in the top end. A flat bottom board although fast will be hard to control and
will bounce a lot.
Tuck on the rails controls how easily the board will release water when in a
turn. Hard rails will be fast in the straight aways but when it comes time to
jibe they will skip and bounce rather than bite. Hard rails also help with
upwind ability of a board, hence they track better. Soft rails will not
release water as easily as hard rails and thus will stick to the water better
in tight jibes.
Rail outline decides the turning radius of your board. A real curvy outline
will turn on a dime and accelerate quickly but not track as well upwind. A
straight outline will track upwind like a yacht but won't turn as well or in
such a small radius as a board with a curvy outline. Outline also has to do
with where you put the wide point of your board. A wide point forward will
help stabilize the board in the low end and top end of the boards speed but
you loose early planing. If you move the wide point back you start to gain in
early planing and jibing but may be hard to control at high speeds. If you
notice most boards keep their wide points near the middle because this is
usually a good happy medium.
Wetted Surface Area
Wetted surface area determines the speed characteristics of the board.
Maximum surface area aids in early planing but at the sacrifice of top end
speed. Minimum surface area gives you maximum top end speed. This is why
speed boards are hard to get onto a plane but once you do they take off like a
rocket. Finding that top end speed and early planing are tough factors to
Rocker works with the outline curve to determine how turny your board may be
but the final goal of rocker is to provide speed in rough conditions.
Although a flat bottom board would be fast, it would only be fast on flat
water. Introduce a few bumps and this board is no longer fast. Add some
rocker in the tail and you'll get the speed back. Too much rocker will cause
the board to be slow but for wave boards this is what you want. Wave boards
use the waves power to propel itself while slalom boards rely on sail power
and need less rocker. Nose rocker helps you when you are in steep chop and
you don't want to spear any incoming waves. Extreme nose rocker is usually
found on waves boards and moderate nose rocker on bump and jump boards but not
usually on slalom or course boards. I have always felt that a little more
nose scoop on Slalom board would help with their down wind ability and it the
least give you more security of not going over the handle bars when you are
submarining. Just my opinion of course.
With these often conflicting variables you have decide what the design goals of
the board you want are. Once you have that down it is just a matter of
finding that right balance. If you can't find what you are looking for you
can always make your own. Many board makers today started that in the
business because they were unhappy with what was available to them.
Apparently many agreed and thats why they are in business. Good luck and may
balance be with you.
Marc A. Lefebvre (firstname.lastname@example.org)
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