Using kiteboarding kites as sails

[sailor4life7777]

Hi guys does anyone have experience using kites as sails. I know there are several companies that provide automated systems like wingit kite boat system in Germany and skysails. Does anyone have experience using these kite boat systems or has anyone been able to successfully diy it with regular kiteboarding kites? I'm investigating the possibility of using kites on a 34' catamaran. Thanks in advance!!

[Overdue]

I used to windsurf for years and started to seriously look at kite-boarding, and then life happened. I have also sailed all kinds of boats from 15' - 32', lakes, bays and open ocean coastal cruising. I have no experience with what you are suggesting, but, IMHO, I would check the weight of the 34' cat and contact the kiteboard kite manufacturer, and ask about tolerances and stress loads on the kite. Sounds creative, but can the kite and its lines handle the stress loads created by a 34' cat purring along at whatever speed?



If, on the other hand, the kite is manufactured for your intended purpose, to tow a boat, then it should be doable. I could not resist doing a little research before completing this post, and I found a video of a kite pulling a 12 ton motor boat 4.5 knts in 6.5 knts of wind. Did you see this? Very interesting. Good luck, check back and update on where you go with this.



https://www.facebook.com/kiteboatsys...7481618596120/

[JPA Cate]

@sailor4life,

Sorry, you're not sounding like a sailor at all. Your needing to get real about what you face.

Ann

[tamicatana]

I have your answer.

I’m selling a Dave Culp OUTLEADER kite that was for my ex-F-27GS trimaran.

I’ve got pics of us trying it on my 40’ cat recently. It worked but is a bit small.

If interested, dm here and I’ll reply with my email and send pics etc

[Franziska]

https://m.youtube.com/watch?v=IayhloX3wU4

[sailor4life7777]

Originally Posted by tamicatana

I have your answer.

I’m selling a Dave Culp OUTLEADER kite that was for my ex-F-27GS trimaran.

I’ve got pics of us trying it on my 40’ cat recently. It worked but is a bit small.

If interested, dm here and I’ll reply with my email and send pics etc

I dm-ed you

[scargo]

During the last Vendee Globe a french company started providing a kite that can be used in place of jury rig in case of dismasting.


https://www.tellerreport.com/news/20...yUpQstYKD.html

[tamicatana]

Originally Posted by sailor4life7777

I dm-ed you

I replied

[SteveSadler]

It is certainly doable, but kites top out at 20 meters, so a bit small to generate much speed. The biggest hurdle is launching and landing the kite. This requires a drift launch which can be quite dicey,(I've done it). Also it can fall out of the sky in light winds, and get all tangled up. Another method is to rig a short mast, haul it up by a line attached to the center of the leading edge, luffing it, then anchor the control bar on the windward rail and sheet in. The power is directly transferred to the anchor point, with no stress on the mast.

[Ifitsworthdoing]

That’s exactly our plan - we are commissioning a 34 ft catamaran without a mast and intend to cruise on solar electric power augmented whenever suitable by kite sails from the French manufacturer Libertykites. We’ll be trialling their 10 sq. meter model with our dinghy tender this summer while the cat is being built, and all going well will be ordering their 20 or 40 sq. meter model for the main ship.

[Franziska]

Originally Posted by Ifitsworthdoing

That’s exactly our plan - we are commissioning a 34 ft catamaran without a mast and intend to cruise on solar electric power augmented whenever suitable by kite sails from the French manufacturer Libertykites. We’ll be trialling their 10 sq. meter model with our dinghy tender this summer while the cat is being built, and all going well will be ordering their 20 or 40 sq. meter model for the main ship.

Btw. Interesting details on kite steering in the video I posted earlier..

[zstine]

The Libertykite is not what you want in my opinion. It is not a "power" kite like a kite boarder uses. It has 2 lines with no way to control power or steer the kite. very limited usability, like emergency down wind sailing only.... and the price doesn't seem to reflect the lack of technology.



You want a power kite that can be controlled, preferably automatically. The video Franziska posted uses a wing commander. This allows you to take advantage of the added apparent wind speed you get from maneuvering the kite in figure 8's. You can see the kite doing that in the video when he's going 12knts dead down wind. So, if you are in 10knts of wind apparent on the boat, the kite may be seeing 20knts apparent on the wing. unfortunately wing commander price is not advertised and they are probably 1 off builds, so expensive... maybe more than a mast! I'd go Arduino and make my own, but I'm geeky like that.



WingCommander RC Tech

[waterman46]

Originally Posted by Ifitsworthdoing

That’s exactly our plan - we are commissioning a 34 ft catamaran without a mast and intend to cruise on solar electric power augmented whenever suitable by kite sails from the French manufacturer Libertykites. We’ll be trialling their 10 sq. meter model with our dinghy tender this summer while the cat is being built, and all going well will be ordering their 20 or 40 sq. meter model for the main ship.

Its fun and we need experimenters pushing the envelope, but dont get too far away from where you could be saved by more sensible mariners.

[seandepagnier]

Originally Posted by SteveSadler

It is certainly doable, but kites top out at 20 meters, so a bit small to generate much speed.

He is doing 12 knots on 7 meter kite... This takes 10 times the power of going 4 knots.

The biggest hurdle is launching and landing the kite. This requires a drift launch which can be quite dicey,(I've done it). Also it can fall out of the sky in light winds, and get all tangled up. Another method is to rig a short mast, haul it up by a line attached to the center of the leading edge, luffing it, then anchor the control bar on the windward rail and sheet in. The power is directly transferred to the anchor point, with no stress on the mast.

There are also "hydrogen-filled" kites that you can set up in light air and they barely float so can be used in the lightest and failing winds. Then in a trimaran, you could re store the hydrogen in the amas without needing to use a very high pressure. The hydrogen also useful for energy storage at anchor, and can power a cooking stove.

For higher winds, perhaps a hard-wing kite like a tethered glider is more suitable as it can use a single line, and servos with control surfaces on the kite itself. These have higher efficiency as well, and so can be a smaller size, allowing them to work in very high winds by minimizing their flying pattern. A hard-wing kite would be in theory easier to "land"

[flightlead404]

Originally Posted by seandepagnier

He is doing 12 knots on 7 meter kite... This takes 10 times the power of going 4 knots.



There are also "hydrogen-filled" kites that you can set up in light air and they barely float so can be used in the lightest and failing winds. Then in a trimaran, you could re store the hydrogen in the amas without needing to use a very high pressure. The hydrogen also useful for energy storage at anchor, and can power a cooking stove.

For higher winds, perhaps a hard-wing kite like a tethered glider is more suitable as it can use a single line, and servos with control surfaces on the kite itself. These have higher efficiency as well, and so can be a smaller size, allowing them to work in very high winds by minimizing their flying pattern. A hard-wing kite would be in theory easier to "land"

I suppose storing hydrogen on board is no worse than propane, maybe even slightly safer since its lighter than air. But I'm not sure the energy needed to recover it is worth it. Probably more efficient to make more hydrogen via electrolysis