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Old 25-04-2014, 10:04   #1
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Let's go fly a kite!

This thread is to design the best kite for cruising and to follow it's construction and implementation. All ideas welcome!
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Old 25-04-2014, 13:15   #2
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Re: Let's go fly a kite!

Thanks for not posting (yet) I didn't get a chance to finish my post- work called!
I want a kite that will preform like a large spinnaker but not the trouble- basically:
1. will float in light air, or put up a smaller version and have it pull steadily when the waves are making it difficult at the air-ocean interface.
2. will pull consistently and with minimal trimming
3.will be retrievable in a gale or worse.
4. will float high in the air- higher than my mast and preferably 2-10 times higher.
Background: I hate going down wind! Why? because the sails are all so unstable! Even my jibs slat together when going over swells downwind, and the main should just be stowed- it can actually be quite dangerous. So why not make a sail that is designed for downwind sailing! One that you can use with other sails, but will not be a big problem on deck or for steering...
Why not just make a big asymmetrical spinnaker? A big sail like that has its advantages- I don't think you can find a better 1-3 knot sail, but when the wind picks up and your heading down, a kite might be able to do a few things your current sails cannot do. For example:
A kite can get clean air above the waves, the mast or whatever! This is why the old square riggers used their topsails in a blow.
A kite can power you life raft, and make it easier to see!
A kite can work with all your other sails (under specific conditions) and give you even more push. (It may just be one or two knots/hr more, but you know how that adds up in 24 hours.)
Flying a kite should not require new, expensive equipment (though I don't know on this point.)
I can think of other possible advantages, but the above is enough for me to try a kite on my cruising boat.
Proposal:
How about a simple sled kite, about 10 feet across and 20 feet long to see how it works? I would place a "zipper" in the center, where if it got out of control it would part in half and fall into the ocean. The zipper would be controlled by a smaller trip line.
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Old 26-04-2014, 14:09   #3
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Re: Let's go fly a kite!

Newt -
Lots of interesting stuff on Google, under kite sailboats, kites for yachts, etc., if you haven't already seen it.
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Old 26-04-2014, 14:18   #4
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Re: Let's go fly a kite!

This design is best...
I think helium is the way to go, but you need a cheap way to make it for this idea to work. It is easy to make hydrogen from solar, so a kite lifted by hydrogen might be viable, reel it in and just let the gas out before it comes aboard.

I had a 10ft blimp and it takes a lot of gas to float it, it has a lot of pull in a breeze. Just a plain balloon works.

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Old 26-04-2014, 14:24   #5
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Re: Let's go fly a kite!

I have a parafoil stored in my Life raft and one in the ditchbag just so we're not at the mercy of currents etc. works in the dink don't want to find out about the raft!
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Old 26-04-2014, 16:21   #6
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Re: Let's go fly a kite!

Quote:
Originally Posted by Kalinka1 View Post
I have a parafoil stored in my Life raft and one in the ditchbag just so we're not at the mercy of currents etc. works in the dink don't want to find out about the raft!
Yay ! Someone else who has the same idea. I've never had much enthusiasm for modern kites as used for kiteboarding, purely on sensual / aesthetic grounds, but this seems to me the Perfect application.


I took it Newt was imagining recreational, rather than transportational uses though, when he wrote the original post ? ? ?

ON EDIT: on actually reading the SECOND post properly, I see I was mistaken. My bad!

... certainly it can be very enjoyable, verging on idyllic, flying a kite from a boat, while sailing along in settled conditions on a beautiful day, and a great excuse to do absolutely nothing.

It's an on-the-water pastime I was introduced to in adolescence by my co-owner.

It does require extra vigilance for overhead lines, though!

Occasionally, at least in my part of the world, these run across major distances, even from the mainland to islands, and can be so far up as to me almost invisible, although in such cases they typically have marker balls to warn aircraft...
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Old 26-04-2014, 16:55   #7
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Re: Let's go fly a kite!

OK, Ill take a shot at this one as I (currently) am far more a kite guy than a sailing guy.

Newt, I believe you will find that a simple sled like in your first post will be unwieldy once it gets big enough to generate the sort of pull one might need to actually pull anything.

If you want to use a kite for a downwind sail, you should look at the NASA wing design. Designed for just about exactly what you are looking for, and as close to what you are looking for as I think you are going to find. The design might be "fun" to try and launch from a boat with other rigging, but they could be recovered from water if it went in, and larger ones do make a ton of power. People have sailed behind them before.

If not that, I think something in a larger parafoil might work. BUT... size does not equil pull on the line/lift. Most of the large parafoils do not pull/lift all that much - single line kite folk like big impact in the sky, but are generally not looking to lift their anchor off the ground. My biggest kite is 250+ square feet, and can still be easily hand flown from its low wind threshold of about 5 knots up to about 15-17. I have flown it in as much as ~25, but it took two men to pull a bight in the line. Most any celled parafoil is going to be a problem over water though, if they go in, they fill with water and become really effective sea anchors - to the point they can be difficult to recover.

High aspect traction kites (those designed to pull, and used as sails for folks that ride kite buggys like myself) come in a variety of sizes, and are designed to pull, but work best in a close/beam reach. While they can be flown up into the wind cone (close reach) or down wind in what would be a broad reach, they are not at their best running with the wind (they generate significant lift from foreword speed, and function more like a wing than a sail at that point. Bummer with these is they are a soft foil and are really unsuitable for a launch at sea.


The inflatable single skin kites the kite surf guys use are designed to be water re-launchable, and make a ton of power. I cant speak to their performance personally, as all my traction kiting is land based.

Low aspect ratio traction foils, (QuadTrac's from 20 or so years ago come to mind) did better running with the wind, but make less power out on a close/beam reach.
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Old 26-04-2014, 17:05   #8
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Re: Let's go fly a kite!

I did a little looking in my kite circles, and found that kite legend Peter Lynn has this fairly expansive article posted on using kites as sails:

Peter Lynn Himself - Kites_For_Yachts **

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Old 26-04-2014, 19:13   #9
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Re: Let's go fly a kite!

Thank you, I have read the Peter Lynn article, but it doesn't hurt to repost it here. The kites used for kiteboarding sound like a good place to start, and can be purchased reasonably. The only down side to these type of kites is they can suddenly produce a ton of lift and then very little- I was kinda hoping to find a design that I can loft in good winds and leave it there till nightfall.
The parasail may be what I want, but in the midst of everything maybe I can just say what I don't want.
I don't want
1. A standard parachute. It is being used, but I want something that will have some lift, to get it out of the boat's windshadow.
2.I don't want an acrobatic kite. I am trying to sail the boat, often solo, so more work is not in my game plan.

And yeah- I think a smaller kite for dingy/liferaft work would be great to get spotted! In addition to providing a bit of propulsion.
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Old 27-04-2014, 10:33   #10
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Re: Let's go fly a kite!

Basically any well built single line kite can be lofted and left alone... but I can't think of any that could be handled by one person that could be flown off a boat (within the size context of this thread/forum) that would actually offer any measurable pull in terms of moving 30-40' of cruising sailboat. Most larger single line kites are launched 100-150' downwind from a previously fixed tie down point. Small single line kites (up to 20-30 sq.') can be hand launched, but larger stuff almost never. When dealing with wind inflatable kites (parafoils...) above 300 sq.' most kite guys recommend a crew to launch. Many guys prefer a crew of three to launch even a 250 sq.' parafoil. One at the tie point as a safety observer, and two holding the front of the kite open to the wind, then guiding the mouth of the kite into the sky at launch.

I do think you are going to want something with no sticks/spars. Either inflatable (like the kitesurf kites), parafoil, or NASA wing (basically a modified parachute). Anything with sticks in it gets unpleasant to handle once they get big. My largest sticked kite is a 20' delta, and its frame is 3/4" fiberglass poles, they are heavy and can put holes in the kite or whatever else they hit if the kite doesn't behave. Sticked kites are also harder to store - the sticks get in the way.


The kitesurf kites are about the only thing I can think of that produce substantial pull, that can still be launchable by a single person, and are water launchable - but they are all multiline, controllable kites. Their popularity has driven their cost down substantially as well. I would guess that one could add a tail on a "Y" bridle to increase stability and fly it with less attention. Might be the direction to look at.

If your experience with stunt (acrobatic) kites was in the realm of small twitchy two line kites, you might be surprised how stable larger multi line traction kites are. Many dual line kites will happily self steer if the two lines are secured at a width wider than the bridle attachment points. They just roll back and forth as if tracing the top of an ellipse. (still probably more work than you want to handle though while running the rest of the boat solo.)

I've never seen anyone "fly" a parasail rig, other than for it's intended use being towed behind a powerboat dangling a tourist into the boats wake.

We did fly a fella in a paraglider as a kite once, and that worked well as a novelty, but again this design was not built to pull heavily against a secured line.

A smaller parafoil would be a great addition to a life raft, and have been used this way for many years. Some were fitted to lift radio antenna to increase range over the visable horizon. Others have been used to hoist radar reflective material to increase radar visibility.
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