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PostPosted: Wed Sep 11, 2002 11:10 am 
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Simplicity itself this, tried this yesterday, tie a length of 2 to 2.5 mm line to your harness hook (slightly longer than your chicken loop, on the other end put a small leash style clip. On launching the kite, put the clip around the line just above the chicken loop or snap shackle ring if using one.

Effectively you are now attached to the kite via a weak piece of line (in the case of 2mm poly – 50 kg breaking strain, 50 kg is probably a bit weak. Really you need something that will break slightly below your body weight, so you need to experiment in the garage).

This means that if you loose control of the kite or a gust hits, the chord will break releasing the kite to the leash, eliminating the time needed to release your snap shackle, or if hooked to the chicken loop attempting to get out of it – usually impossible by all accounts.

Once at the water hook into the chicken loop & unclip the thin line, or if using a shackle - hook into the harness line, attach the shackle & unclip the thin line. Before leaving the water reverse the process.

The advantage of this is that you can still control the kite with your chicken loop while landing of launching, but with no risk of getting lofted or dragged by a badly rigged kite or squall etc.

You would need to experiment with different line strengths depending upon your weight & how powered up you ride. But I think I reckon you could even use a line strength above your body weight, given that the force required to accelerate somebody violently is far greater than your body weight (Force = Mass x Acceleration). Although if using a stronger line, you want to consider attaching it with a quick release.

Seems so simple, an extra level of safety, which you could choose to use or not depending on ability & the conditions. Would potentially prevent many of the accidents that seem to occur on land.

Any thoughts?


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PostPosted: Wed Sep 11, 2002 12:59 pm 
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Great idea! I tend to overcomplicate things (surprise!), and your single line is a very simple, direct and I suspect reliable way to provide a weak link. I like the fact that there is only one link and in one location.

It will take a bit of trial and error to develop this for individual riders. The line selection will be a function of rider weight, kite size vs. wind speed/gusts and to some degree how aggressively the rider flys the kite until the weak link can be bypassed. Of course to reduce the variety of links needed it would be good to fly pretty conservatively until the link can be bypassed. During trials the kiteboarder should be holding the bar and in that way should be able to save their kite from damage as a result of premature releases.

Congratulations again! I think your idea once spread around could save some riders injury. It should also give lots of others some piece of mind during the critical launch and landing phases of kiteboarding.

What do you want to call it? The Greeny Link???

Rick Iossi


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PostPosted: Wed Sep 11, 2002 1:14 pm 
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That sounds good greeny.
Only thing I'd watch out for is, if it breaks when you're depowered the kite will jump to full power in a split second. This happened to me once while putting me feet in straps starting off from the shallows, the rope holding the shackle broke and the kite went from full depower to full power in a second. In 15-17 knots with a 16m kite it was quite a ride.
Another thing to remember is that if you use double line it will be twice the breaking strength, or nearly, I reackon.
Jo


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PostPosted: Wed Sep 11, 2002 1:35 pm 
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I really intended that you would use this link when not riding - cause thats where the majority of accidents seem to happen, once you start riding by-pass it with your usual shackle or chicken loop. I guess for riding & jumping the force you experience is many times your body weight, depending upon level. A weak link to cater for this would be too strong to prevent lofting I would think.

Rick I see wher you were coming from now, if you had 2 links one for on the beach & an extra one for riding, you could then set the 2nd one to break when things got out of hand on the water. So say a 70 kg link for beach handling & then an additional link of 80 kg upwards to take it up to 150 kg for riding. So with experimentation you could produce a set of standard links for different body weights & riding styles. You really need a strain guage load survey to establish exactly what the forces are.


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PostPosted: Wed Sep 11, 2002 1:45 pm 
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Re: I really intended that you would use this link when not riding - cause thats where the majority of accidents seem to happen.
I agree and understood, all I'm saying is be carefull about using a weak link that might break when you're not expecting it, maybe with the kite fully depowered while walking it on the beach. Have to let go quick if it does, see what I mean?


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PostPosted: Wed Sep 11, 2002 2:03 pm 
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Jo,

Yeah I see what you mean, I was really replying to Rick with that last one. I agree you would have to be ready to let the kite go should the link suddenly go (you would defintely need a leash with this set up).

When your shackle rope gave in are you saying you got launched before you were able to let go or did you react by trying to hang onto the bar.

Tony


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PostPosted: Wed Sep 11, 2002 2:10 pm 
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I would never try something like this.
Safety must be reliable. This weak link is not. Lofting is not the only danger. A line that coudnt bear your weight, could still kill you by dragging into a hard object.

If you want a real "dead man" safety system for lauching, all you need is a spare line attached to the beginig of the chicken loop. Take this line in one hand, put this hand at he bar and hook it to the harness. Now you have a "just release the bar" secondary chickenloop.

I think many times at this type of safety.
Other application could be a fixed loop with a weak velcro link at the bar. If you put your hand over this link, it will hold. If you take your hand, the loop will open.

Keep thinking
Henan


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PostPosted: Wed Sep 11, 2002 2:20 pm 
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I agree, leash is ok with me, always use one.

When the rope holding the shackle broke I had just got into the water with the kite fully depowered, I was putting my feet in the straps when I heard a wack which was the depower loop smacking into the bar. The kite went from full depower to full power immediately and just took off like a mad thing as you might imagine, didn't let go because it headed out to sea, just held on and enjoyed the ride, but this is another reason I don't use a shackle anymore.

Don't get me wrong I think your idea for a weak link is great.
You're right that you really have to get the breaking strength right though to avoid something like the above happening, or as you said it being too strong so it won't break when you want it too,(any physics techers out there?)
A line will also tend to get weaker as it ages and gets stretched or rubbed, also weaker if you tie a knot in it right?
Maybe sheathed fishing line would be better, less risk of wear, what you think?
Hang loose.
Jo


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PostPosted: Wed Sep 11, 2002 2:29 pm 
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Hi hernan,
Re. If you want a real "dead man" safety system for lauching, all you need is a spare line attached to the beginig of the chicken loop. Take this line in one hand, put this hand at he bar and hook it to the harness. Now you have a "just release the bar" secondary chickenloop."
Sorry but I didn't follow that, could you explain it more? Are you saying use a line with one end attached to the chicken loop and the other you hold on the control bar, while hooking this line into the harness to depower the kite? Therefore as soon as you let go the only thing that's attached is the leash?
Jo


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PostPosted: Wed Sep 11, 2002 3:08 pm 
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Hernan,

To accelate a person violently takes an awful lot of force, Force = Mass x Acceleration. if the weak link was set at around your body weight, I reckon it would break before this could occur.

If this was also attached with a quick release shackle then the weak link could cater for the sudden enormous panic causing viollent acceleration, the one which you have no time to react & release. In this case it would definetly snap. The case where you had more time too react you could yank the shackle.

As the rope gets older it will get weaker & so release sooner. Also as it's only a cheap peice of line, you could afford to change it every few sessions.

Tony

Tony


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