Sunday, September 27, 2009

Wind Thresholds and Kitestration

On the rare days that the weather is suitable for kiteboarding, I always seem to have an equipment problem. Most recently it was a busted pump. I had to pump like, 1000 times to inflate my main kite bladder instead of the usual 40. At the end I was tired and sweaty and the kite still wasn't fully hard. I thought it would be alright, but after just two minutes of riding, it folded in the middle of a power stroke and dropped from the sky like a scorched moth. It nearly self-destructed in the shorebreak before I could swim to it and drag the whole sandy, algae-entangled mess out of harm's way. Shit shit shit shit shit.

Windsurfing has been better to me. I managed to procure a loaner formula boom last week so I can rig my 9.8 again. (Thanks, you-know-who.) Friday I had a good sunset session in onshore winds, and today another good one in offshore winds. Neither sesh would have possible on kite gear, because of the lightness, flukiness, and / or direction of the wind.

All this got me thinking about the wind requirements for windsurfing versus kiteboarding, and inspired me to make the graph below. It shows the approximate wind needed for longboard windsurfing, formula windsurfing, bump & jump windsurfing, and kiteboarding. (Windsurfing on a big freeride board would be something intermediate between the curve for formula windsurfing and B&J windsurfing.)

Anyway, all the types of wind-riding are pretty cool in 15+ knots, but their rideability and planing thresholds are different below that. Here's why I drew the curves like I did, based on how each toy's handling changes as the wind increases:

Longboard Windsurfing-
0: Can't move.
1-4: Move slowly in any direction with the daggerboard down.
5-8: Move well in any direction with the daggerboard down, but have to force board to rail.
9-12: Board begins to rail itself and go upwind great. Railing straps can be used if the wind is steady. May be able to surf swells with the daggerboard up.
12-15: Powerful upwind with the daggerboard down, and can plane off the wind with the daggerboard up.
15+: Full-power planing with decent angles possible without the daggerboard. Have to be skilled with railing straps to sail with the daggerboard down.

Formula Windsurfing-
0: Can't move.
1-4: Slow slogging, limited upwind ability.
5-7: Stable slogging and ok upwind. No planing; at least not without constant, aerobic pumping.
~8: Concerted pumping will initiate planing, but hard to go upwind or downwind on plane.
~10: Less pumping required, ok angles while planing.
~12: Little or no pumping required to plane; high upwind and deep downwind angles possible.
~15: Intensely powered-up with awesome speed and angles and fully-planing jibes. Beyond this it gets kinda scary for most people.

Bump & Jump Windsurfing (manouverable board just big enough to float the rider)-
0-3: Can't move
4-8: Slow, precarious slogging with little or no upwind ability.
8-13: Stable slogging and ok upwind. No planing unless riding a wave.
~14: Can pump onto a plane, but not much power for jumps or manouvers.
15+: Few pumps required to plane. Good power for jumps, jibes, etc.

0-6: Can't launch or fly kite.
~8: Can launch kite, but hard to keep it in the air.
~9: Can fly kite and body-drag ok, but not enough power to get up on board, and can't relaunch kite from water.
~10-11: Can ride board, but only by constantly working the kite. Can't stay upwind and tough to relaunch.
~12: Can ride and stay upwind, but have to work the kite a lot.
13+: Can "park" the kite and ride steadily most of the time. Can jump and stuff.

The thing is, with kiting, even though you have the lowest planing threshold besides formula windsurfing, you're basically dead in the water below that threshold. And the threshold is actually higher than it seems from the chart, since you have to account for lulls in the wind. Like, even if the wind is averaging 12 knots, if there are lulls to 8 knots, you're in trouble. I think that's why most of the kiters around Fort Pierce only go out when the average is around 15, and why, since the wind rarely reaches 15 between May and September here, the kiters disappear for the summer.


Catapulting Aaron said...

The graph is perfect. Nice work. Sorry about your kite gear :(

Johnny Douglass said...

Get rid of the stoopid kite. It's not worth the headahes. Maybe you can apply what you get for it to the price of a new formula boom with a better head.

Scott F said...

James great work on the graph . It really helps to understant the differences. Like Ive said before, your knowlege and ability to convey the knowledge of windsurfing is amazing. You should write a book. Thanks

CMS said...

I'm glad I found your blog. It is the most technical and informative out there, especially for Floridian wind sports enthusiasts.
I moved to FL four years ago from a windy, wavy locale and thought I'd learn kiting to increase my lightwind fun days. Long story short, I can windsurf on big gear in the same wind speeds as I can kite, with the big difference that if it's marginal and the wind drops I can get home on a windsurf, whereas it's swimming and untangling line time on a kite.
So far this winter, we've had (in Miami) three or four 83L/4.5-5.6 days where the kiters didn't even show up and for the Summer I'm looking at Formula + 10m sail. The 12m Waroo is away for good.

I wish I had found your blog before I wasted my time and money on the kite!