[ksurf] Re: big fat boards
- In a message dated 99-10-02 10:00:24 EDT, burgy@... writes:
<< I'm thinking of putting some concaves in to generate grip & lift, any
words of wizdom regarding that? >>
You'll probably find that while they may generate "grip" & lift, they also
generate extra work (to build), weight, drag, & directional stability (hard
to turn). Flat is fast & loose, and easy to build.
<< get 2 fins & attatch them to the board at say 45deg with the tips pointing
to the outer edge of the board so its semetrical along its middle.
would the side ways lift generated by these fins cancel each other out giving
only vertical lift or would the turning moment generated by both these fins
be in the same direction making this idea a non starter? >>
With symetrical foil shapes, & centerlines both aligned with the board's (no
"toe", in or out), the horizontal lift will be in the same direction (upwind)
for both fins, since they will have the same angle of attack (when viewed
from above), so they won't cancel each other out. They may or may not create
vertical lift, depending on their angle of attack when viewed from the side.
Depending on where the fins are located longitudinally, the vertical lift may
just add to board drag, by changing its angle of attack to an innefficient
angle (fins lifting tail reduces board aoa & increases surface contact).
Personally, if I was to experiment with board width & fin size*, I'd leave
the other factors on the "fag packets" for now, & just use a plain flat
bottom & vertical fin(s). Otherwise you won't know if your new board works
great because of the concaves, fin size or dihedral, or board width.
*which I think is a good idea
- Please do yourself a favor and copy an established design. The type of
experimentation you are talking about never yields good performing
boards unless you are willing to build about twenty variations and
thoughly test them one at a time. Naish and Jimmy Lewis and F-one have
done this already, copy them and you will have a board that works.
Innovate, and be ready for an interesting but disappointing result.
Having innovated in the past my self I know! I am probably the only guy
learning to kite surf on an innovative 16" wide single fin minimal
rocker board, hmmm is it me or the innovative board thats the problem,
only time will tell.
Good Luck and Copy
oh yeah don't smoke those fags, those things will kill you as sure as an
overpowered kite on a rocky beach.
- Hi Burgi!
> with the trend for super fat boards and massive fins in wind surfingI've made my own board and it looks quite like what you're looking for.
> giving true light wind planing performance has anyone tryed short wide
> boards for kite surfing?
It's 190cm long, 50cm wide with a slightly conkave bottom, long flat section
in the back of the rockerline, has a square-tail and boxy rails as it is
quite thick (max. 8cm).
It planes verry quickly and is a real lightwindwonder. It is not so easy to
jibe because the tail doesn't sink and you are likely to dive the nose if
you don't care. Maybe a diamond tail would have been better. Another
drawback of the wide tail is that if the wind get's stronger it's harder to
dig the rails into the water because the big surface generates a lot of
But I'm still loving this board because it planes so fast and you can ride
it flat, flying upwind when the wind is not so strong.
(I've promised to post some pictures of it, but the guy who has the photos
went fishing for two weeks, so they are still not scanned, but I promise to
post them as soon as possible)
Good winds to all
PS: Since Wednesday each day on the water in winds from 20 to 30 knots,
yesterday rather 30kn, and for today promised 15 to 20.
It's windy in Austria and still warm (24°C). :-)