Sunday, April 5, 2009

Windsurfing Quiver Spacing and Color Coordination


In human nature there is a fascination with sleek, symmetrical shapes. The fascination is most powerful when an object's form embodies its function as a tool, a toy, or a living thing. It's why girls draw cats and horses, why men collect knives and guns, why fly-fishers pursue trout, and it's one of the reasons I love windsurfing.

There's an obsessive satisfaction for me in ordering and organizing my windsurfing gear; blending aesthetics and "utility". One of the juiciest problems to solve is quiver spacing. The object is to acquire an array of windsurfing equipment that will cover the range of wind and water conditions you sail in, with minimal gaps or overlap. Money, storage space, and sailing time set limits on how much stuff you can have and use, so spacing of sail, board, and fin sizes really is key to maximizing your stoke:stress ratio.

Today I had a nice quiver-zen episode, with a rising wind that started perfect for my 8.7 sail / 150 liter board, then got perfect for my 6.6 sail / 106 liter board. I'd never made that particular transition before, but it was awesome how well it worked. It made me feel good about having given my in-between-sized 7.8 to my dad, clearing up some space. (In the pictures, the blue combo is the 6.6 / 106 and the yellow combo is the 8.7 / 150.)


Below 6.6 I'm still working on my spacings. I want to have sails with optima separated by about 3 knots in wind speed. When I had a 5.8 and a 5.2 they were only separated by about 2 knots, so it was hard to decide which to use. Now that my 5.8 is kaput, the jump straight from 6.6 to 5.2 is doable, but a bit much. Since the 5.2 is aging, I'm planning to replace it with a 5.5. Then I'll have nice 3 knot spacings from 6.6, to 5.5, to 4.7. (The way I'm figuring out the spacings is with my automatic sail size calculator spreadsheet. It's a good tool for this sort of thing. ) Below 4.7 I have 4.25, which is only 2 knots from 4.7, and 3.5, which is 5 knots from 4.25. 4.0 would be better, but since I rarely use my really small sails, anyway, I'm not in a rush to fix the spacings there. Eventually when I get it all worked out it's gonna be like this:

8.7, < 15 knots
6.6, 15-18 knots
5.5, 18-21 knots
4.7, 21-24 knots
4.0, 24-28 knots
3.5, > 28 knots



John I said...

Keep in mind that if you blow out a sail in the most often used size with that perfect spacing, you are screwed for the short term if the wind keeps going off while the failed sail is in for repairs, or replacement. I'd have some serious overlap in the 5.0 to 6.8 area....

James Douglass said...

John- That's a very good point. It doesn't hurt to have some spares and overlap, especially in your most-common wind range. I'll be hanging on to my 5.2 for that reason. It's also nice to have overlap if you're sharing gear with a buddy of similar size and skill.

Scott said...

For what it's worth, here's what I use:
- 6.9, 15-18 knots (or I just go surfing or kiting,
if I happened to be a kiter, or bicycling, or work
in my garden, or ...) I don't use this much
- 5.9, mid to high teens
- 5.3, high teens to low 20s
- 4.7, low to mid 20s
- 4.2, mid 20s to low 30s
- 3.7, mid to high 30s
- 3.2, 40 plus

I like to sail slightly over-powered; I am pretty
lit up on the 4.2 in the low 30s unless i flatten
the sail out pretty well. But modern sails do
have a good range; I can use the 4.7 into the
low 30s if I down- and outhaul it pretty far.
It's twitchy, but usable.

I use a smaller fin size when the wind is at the
upper end of the range. Reducing the fin size
really helps by reducing the lift out of the water.

My largest board is a 100l JP Freesty, which is just
big enough to hold the 6.9 if what I want to do is
blast around instead of doing some light-wind

Catapulting Aaron said...

Hmm... I think it also could depend on where you live. Where I am lots of people have a 4.7 and a 5.2 or 5.3. Or if they have a couple more pounds they'll go 5.0 to 5.5.

May seem like too narrow a space by your calculations, but a lot of the breeze we get is right around those windspeeds, so it's nice to be "just right powered" when the wind is blowing something more like 18-23 or 20-26 or so.

James Douglass said...

Scott- Sounds like you've got things dialed. :)

Aaron- Yeah, I reckon if you live where there's a "typical" wind strength, like 20 knots-ish for SF bay thermals, it makes sense to cluster your sails around that. The opposite would be a place like VA where it's variable day to day and often too gusty and changeable within a day to fine-tune sizes. That's where more size range and broader spacing would make sense.

wsurfn1426 said...

It all depends on where you sail, how you sail, what boards you have.

I have gone from a garage full of gear (Formula to wave) to quiver bag that fits inside my Honda Fit. I don't even have car racks. I have three boards and bring only two.

I personally got very bored with BAF/planing in marginal winds. I enjoy how LWF improves my game when the winds do come. I am sailing way more and am less frustrated since I am less concerned about planing/going fast.

I found that I liked closer spacing in the sweet spot of sail range I use most to take the heat off the selection process. Once I pick a sail, it becomes a tuning process from there rather than a re-rig.

Andy said...

not sure if you were looking for recommendations, but you sure got 'em! : )

I've been on a real minimizing kick lately. And I've never been happier on the water... Less internal bickering over which setup will be perfect leads to more gratifying sessions. But hey, that's just me!

Oh, and color matching is uber-important!! Make sure to get matching shorts and rashguard, too. : )

James Douglass said...

wsurfn- LWF = Light Wind Freestyle? I guess that's one of several approaches to getting more enjoyment out of less gear and wind. Some others:

LBW = Long board windsurfing
LWW = Light wind wavesailing
SUP = Stand up paddleboarding
FW = Formula windsurfing
KB = Kiteboarding
SS = Skatesailing
S = Surfing

Andy- Yeah, so it goes. I'm with you on the minimizing and color coordinating. The other day I wore a blue rashguard with blue shorts on a blue board with a blue sail. Yes!

Frank said...

In the past I always used percent for calculating sail gaps. From the biggest sail to 7.0 15% gaps. From 7.0 to smallest 10% gaps. Usually I ride cambered sails 7.0 and up but RAF sails 6.5 and down. But I do use James sail calculator for fun as my weight changes.

James Douglass said...

Frank- Spacing sails by a given percentage (like 15%) is definitely better than just going by a fixed increment like 1 m2 between sizes. Although the way it works out, two big sails separated by 15% will have optimal wind speeds separated by 2 or 3 knots, whereas two small sails separated by 15% will have optimal wind speeds separated by 4 or 5 knots. At least according to the calculator. So maybe that means you can have more than 15% gaps between your big sails, and less than 15% gaps between your small ones.

wsurfn1426 said...

LWF = Light wind freestyle

racer_X said...

I have been using your calculator, it seems helpfull. However had did you come up with the formula? It does not seems to have any provision that the force created by sail should increase by (windspeed squared)/2.

Here is lift equation for a airfoil

It still seems like a good gestimate.

James Douglass said...

Racer-x: The equation was floating around the web. I suspect it is the result of empirical curve-fitting of a relatively simple equation to a complex process. I.e. it does not try to represent all the physical processes going on, like the lift force you mention or the various drag forces. It just "gestimates" the end result, as you say.