So my dad (who has never windsurfed) asked me this question when he was watching me windsurf:
How much faster would you go if you put a hydro foil where the fin is?
It is an interesting question and one that i do not have the experience to answer.
Im expecting that the speed difference on flat water would be minimal as when you are planing there isn't much resistance anyway but in chop? Imagine just floating over all the chop on a foil without having to bounce and bash through it. hmmmm, thoughts anyone?
EDIT: I've seen foils on "air chairs" for wake boarding and such but never on a windsurfer.
There would appear to undeniably be more drag with a foil. Basic proof: Slalom racers don't use foils.
A large surfboard does not have anywhere near the drag something like an AC Catamaran does, so won't benefit as much.
Windsurfers plane.
Hydrofoils are the fastest craft on the water, see Sailrockets video with av speed of >65 knots.
^^^^ agree for a perfect like comparison you can compare yardsticks for the International Moth and Foil moth and speeds if you like.
Foils are Faster and create LESS drag........ even though windsurfers plane the total area near the back foot in contact with the water (including fins) would be greater than the total area of the foil....... I reckon anyway
i was thinking that in heavy chop the foil might give a large advantage in speed because the foil in under the water. it doesn't give a damn if its choppy or not because its not on the surface. A board planing on the surface hits every bit of chop and subsequently would lose speed but foils wouldn't and i think this could give it a bit more speed and definitely a smoother ride.
i used to airchair waterski a lot and modified my own foils.
The speed record foils are a lot different. The waterski ones that the windsurf, kitesurf and big wave surfers use have horizontal foils bolted to a vertical T piece. Because there is a lot of surface underwater, they provide lots of lift but the drag gets a lot higher the faster you go. To a point where they becaome unuseable - it doesn't take much to max them out. The speed ones are probably quite high drag/ zero lift to start with, and only go fast because you can get a massive hull with a massive rig out of the water and just riding on foils. Windsurfing bigger is not faster
Everyone thinks they should be the future etc but there are lots of problems. I watch those surfers and windsurfers/ kitesurfers use them and roll my eyes. To ride them it's like balancing a chair. you can make them fairly stable, but if you get too high they will cavitate and you loose all lift and drop like a rock. the longer you make the vertical strut the more leverage there is so the bigger the potential kick out of the water (jump) but you have to temper that with control. They are very directional whan landing, and if you dont get it right its a massive stack. Nothing like landing a normal board and the freedom that gives. If you watch footage of any kite or windsurf related foiling they will be going along in a straight line. If you see a jump you probably wont see them ride away (chopped footage) it's because they ate it. The combination of riding the foil and controlling the kite would suck momentus balls IMHO, and I can land inverts on windsurf, kite and foil. I would hate to combine them. Also the skurfing style behind a wake boat would be pretty dangerous IMHO also.
Big wave surfing might have the advantage of skimming over chop (according to laird), but he can afford to dxck around and poo poo various conditions. They are just trying to cash in on the next watersport. Other than that I'd say it's going nowhere.
Select to expand quoteTheSailingMoose said..
So my dad (who has never windsurfed) asked me this question when he was watching me windsurf:
How much faster would you go if you put a hydro foil where the fin is?
It is an interesting question and one that i do not have the experience to answer.
Im expecting that the speed difference on flat water would be minimal as when you are planing there isn't much resistance anyway but in chop? Imagine just floating over all the chop on a foil without having to bounce and bash through it. hmmmm, thoughts anyone?
EDIT: I've seen foils on "air chairs" for wake boarding and such but never on a windsurfer.
too much surface area under the water. fin is only one plane (vertical) foil has vertical and horizntal. Windsurfers have so little in water other than fin anyway. Watch old mate in the footage above. see him balancing sheeted out. He is going up and down, that's because he can't ride for shxt. When you get better you learn to adjust witha bit of lag (skiiing anyway) but the problem with windsurfing is not only do you need to ride the foil but control the rig. Everytime you sheet in or out it would then affect you altitude on the foil so you would have ot counter by leaning forward or back. Like balancing on your chair at school on two legs. you can do it staying still, but try juggling and doing it at the same time. it's just not practical at all.
The normal windsurfer behind is going faster.
Kite board Foils are about to be mass produced, you could adapt this type to a windsurf board??
Johnny Heineken won the bridge to bridge race in San Francisco in September this year on a foil. Smashed the record by 2 minutes. It is definitely faster and for kite boards anyway, just much harder to stay on top of with out crashing big time.
Speed records held in some channel in Africa though they still use only fin for drive and are getting 55 knots plus board speed - both Windsurf and kite board - there are good link on youtube - check it out.
If you're looking for a more stable hydrofoil for kiting, surfing or sailing the twin lateral wing configuration needs to be changed to longitudinal.
Here's a thread where I explain why and how and with examples and dimensions., pages 7 and 8.
kiteforum.com/viewtopic.php?f=1&t=2361561&start=60
