get home kite sail

Not sure if this the right forum. Tom Colvin won't let me install a mast and get home sail on a steel 34' steel dory I am building.Stability problems. I thought kite sails might be a good idea, but soon discovered they are hard to control, so what about a tethered balloon? It could store in a canister with the appropriate inflation tank and be deployed when the engine fails. Could a balloon generate enough thrust to have steerage and maybe make one or two knots? I have no idea about whwre to begin with the calculations. I realize that even if it makes sense (which it probably doesn't) it would take an enormous amount of effort to develop. My boat will never see it. But it's fun to think about. OK you can laugh without hurting my feelings. Any thoughts on this?

 

I understand low aspect ratio kites like those of kiteship are easy to fly and stable.
A balloon inflated with lighter than air gas could fly a series of flags or ribbons along the towing line, thus increasing drag..... just an idea. But the problem could come when retrieving it.
Perhaps you could use an inflatable kite as alternative...
http://en.wikipedia.org/wiki/LEI_kite

Cheers.

 

Or maybe think more than one kite. Fly the first one up, then the second on the same line and so on. If you have enough kites on the same line it would be the same as one big one. I haven't thought about the control though.

Kites can fly to wind as well as any sail. My one friend has one of these two handle kites. You can fly it anywhere you want, even almost directly overhead. Imo if you can get something like that in an over size it will work very well.

Just think how nice it would be if you can get rid of the masts and sails and just sail with a kite...

 

As mentioned the control is the point. The commercial installations (skysails) like this one:
http://news.bbc.co.uk/2/hi/europe/7205217.stm
http://www.skysails.info/
use a computer hanging in a gondola under the kite for the line control. That is a very sophisticated and a very expensive gear.
Kiteship is a bit unmature compared to that.
Any uncontrolled system (you naturally cannot manually control like the smaller kites used for surfing), will pull you the way the kite (wind) likes. Thats not the way to go.
We will have to wait until these skysail systems are getting widely used in the commercial world to be affordable for yachts.
Since 10 or 12 years I am playing with the same idea to install such system on a passagemaking motorcruiser as a coming home backup. Prices are already down to around 250.000€ for a small ship, but that still is ten times the cost of a simple rig.

Regards
Richard

 

No we don't wait untill someone else does it 4 5 c. Skysails have their ideas, I have other ideas.

I'm sure you must have seen these four line kites the guys play with and how well they control. So if you have a kite with four control lines, ok. Then on each line there is a series of different size stops in each line.

The higher stops are larger than the lower ones, so if you have one kite up and it flies, you clip kite no 2 on. The kite slides up the four lines and over the first smaller stops but get stopped at it's own stops.

The wind always pushes the kite up, so it will stay in place but it could also be possible to make it so it can clip in it's own place and stay there. The distance between the kites are preset by the distance the stoppers sit from one another.

Now if you pull any one line both these kites are going to do exactly the same, so you have control over them.

In the same way you can now add more kites, giving more lift and sail power and as controllable as when you had only one.

The sail control should also not be such a big train smash either. If the kites are up and flying and if they are rather large then you are going to need a fairly strong control mechanism. This can be achieved by using three electrical motors that control a mechnism to function similar to the hand controls you get on these small kites.

The only difference in me playing with these things as to sky sails is they have money. I don't so I can't get my projects done.

The wife says if I live to be 500 years old I won't get them all done... which is good, right ?

 

Right Fanie, we all should have projects for say at least the next 100 years.
The kite control is not as easy as you would like it to be (does not matter one or ten). To provide enough pulling power per m² the skysails are elecronically moved to fly a "(8)" figure in the sky. This brings the aerodynamic profile of the kite into the play and enhances the power by about three times over a stationary kite, this cannot be cotrolled by winches from deck. It is as impossible to pull the two steering lines on a conventional kite (or ten of them) in a fast responding manner to get a proper pull towards your heading, if using winches on deck.
If we like it or not, the skysails way is the right one and we just have to wait until the fishing fleets step into that (or competitors), to get it much cheaper.
I´m shure it will not cost more within the next 5 years than a good conventional rig.
Regards
Richard

 

Hi Richard,

I'm sorry but I disagree with you once more.

One of the biggest handycaps we allow ourselves is to think within our own reference boxes.

I have no illusions about the force these sails can make, and especially at a certain height there's even more wind. Which is of course ideal because down on the water we prefer wind still, it's more pleasurable and you don't have to shout when you order another drink

If you have four lines to control the kite, then surely the pull in all four are about the same. So if we pair them two left and two right then it works out.

If you consider the left two lines, if they are on a lever that hinges on it's center then you need little force to disturb the ballance, hence the kite will react. Same with the two right lines. If keeping them moving makes such a big difference.

Imo, if one can only replace the mast and sails with an easy to use kite system it would be great already. Only problem I see is if you have very low wind that cannot sustain the kite, then you will gain having a sail, you can still move a bit in low winds.

Remember the only reason the kites control are considered complicated is because nobody has made the easy to use one yet. There was a time it was impossible to sail any direction other than downwind. Today you are a retard if you think like that.

In a while kites may become the common standard and you'd be a retard if you use a mast and sail. Who knows. Saying wait till someone else has done it first, well, that's what they all say looking at you

 

I do´nt mind if one disagrees here. Nevertheless my statement is right, I used controlled powerkites in the past. (not on boats naturally, at the beach)
Yes the forces are not too high to steer the kite (therefore the electronic control box can operate the skysail), but the pulling force has to be directly lead to the boat and divided from the control lines. Now we have the steering lines left, will you hold them in your hands to operate the boat? All day? Turning eight´s in the air? We are not talking about a dinghy or surfboard, are we?
If you visit the website I linked to, youll get a deeper insight.

"Imo, if one can only replace the mast and sails with an easy to use kite system it would be great already."

I would be happy too, but that is what we are missing, there is no such easy to use kite!
And if the wind is below 3 Bft. there is not even a very sophisticated kite, just a gentle rollin sampan where we can enjoy another drink, before the trouble starts.

Regards
Richard

 

Here is a simple way of controling the kite, as I said earlier motorised.

The angle of the swivel arms will control the kite's height, while one arm moving with the motor pushing it in or out should give you a kite flying left and right, possibly already doing a figure 8.

Holding a kite with your hand on a boat is not an option. You'll get plucked off your lazy boy and flewed all over the ocean and I bet you'd learn some kite skills real quick then.

One day when I get time I may build a model to fly one of these sports kites. Can't be too hard to make. If the motor is controlled with a wind vein or even a compass to determine where the kite is wrt a preset diection, why not.

 

Fanie how do you control a kite that is 200 meter above you? By electronics, nothing else is sensible. The windvane mentioned can determine the surface wind only. And how complicated must a system be if you involve a compass (in the kite), without electronics? How do you do the steering with the apparatus shown? Where does the input signal come from? If it would be easy to compensate these electronic controls, "Beluga Shipping" would have done it in the past five years, since they are involved in that project. Maybe "skysails" would´nt, but Beluga has only a commercial reason and paid for the development.

I have understood your plan right from the first moment, for that reason I said its not the way to go.
And naturally I know the power of a aerodynamic kite, a bit over 1m² lifts a man easily. I have some kite skills.
Regards
Richard

 

I am interest in this idea. If anybody can get it to work it sure will be worth money to them.

 

Mydauphin, it is working and it makes money since several years now. Look at the links above.
Regards
Richard

 

I think kites are interesting and have real potential to reduce fuel and/or provide a lot of fun. However, there are cost issues with the high-tech ones, control issues otherwise, and since this boat clearly has no keel a kite will only haul it on a downwind course with maybe3 points either side.

The issue is, Kelp just wants to get home if the engine fails, and doesn't mind if it's slow. I would suggest a small outboard.

 

Have a look at: http://www.youtube.com/watch?v=qnAC...ABAB9FAC2&playnext=1&playnext_from=PL&index=6

A friend of mine built a kite powered cat and it hit 35 knots numerous times. There weren't control problems, provided you know how to fly the thing, even here in San Francisco in 25K +++

 

I saw that. So no one else shoud try that, and they are so environmentally concerned that he took a bat to the fish he cought. I also didn't know sailboats were so unsafe...