Windspeed vs Height[part 2]

wind height























When I began blogging I wrote a little article Windspeed vs Height. I did some research to learn what kind of flow normaly enters the sail.

Last weekend I had some time to surf on the web, and I read some stuff on Boogie his blog: Speedsailingdesign.blogspot.com

But more intresting for me was his Google Group Speedsailing design files, I found there a more specific graph of the windspeed vs Height. And again a confirmation with less-windspeed you need less twist in the sail.

Lots of (semi-) pro windsurfers know this for a fact. Also read a long time ago something of Dan Kaseler (gaastra saildesigner) that for Formula a sail with little twist worked far better than a sail with lots of twist.

How should we translate this to speedsurfing? This one is quite hard, in the Netherlands you see 2 kind of windsurfers. I am the kind of windsurfer that does use a little less downhaul on a Neilpryde RSR (evoI), that means a something like moderate twist. But there is also another group of speedsurfers that use MORE twist, this can be fast for some speedsurfers that like to sail complete close-the-gap-style.

But for speedsurfing I don't think we should use little twist in our sails, and that is a problem. For slalom little twist is handy, because with little twist you the board bounces less. I think the best slalomsail can't be the fastest speedsail, because when pulling more downhaul the sail deform in multiple ways (not only twist). Maybe some day big manufactors like Neilpryde, North Sails, Gaastra will produce a speedsails-model and a racesails-model.

There is sooooo much unwritten stuff about sailtuning etc. Because it is soo hard to compare, sails are flexible and there are no "hard" measurements possible. North Sails with their DOT in the top of the sail, that is good for amateurs sailors but still if you trim to that DOT for speedsailing you have 80-90% of the best performance you could have...

How do YOU know if your sail is a good a it gets??? GPS is the answer, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare, ride, tune, compare

or maybe you are lucky and know a fast windsurfer that is willing to comment your current settings.

Erik Loots

Erik is windsurfer for 10+ years. In his daily life he is professional in construction dewatering, advisor, troubleshooter. Erik likes adventures, explore and to challenge himself. During his life he is trying to get the best out of it and have respect for the earth, nature and future generations. The modern world is about sharing, in this blog Erik shares his experiences, selfreflection and lessons learned.

2 comments:

  1. D'r is genoeg geschreven over zeiltuning, alleen moet je het wel willen lezen ;)

    Zoek maar eens bij Bol.com of Amazon.com naar "Sail and Rig Tuning" door Ivar Dedekam (ook in Nederlandse vertaling verkrijgbaar),
    "The North U. Fast Course: North Sails' guide to sail trim".
    Standaard-lectuur voor alle (plank)zeilers.
    Zo zijn er nog wel meer dikke boeken over zeiltrim en tuning te vinden :-?

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  2. Bedankt voor de tip Robbert-Jan! Zeil trim etc. heb ik nooit goed bestudeerd, denk dat dit wel goed is om een beter beeld te krijgen waarom het soms wel lukt en soms niet.

    gr,

    Erik

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