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Too tight for a sym

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Contender 541 View Drop Down
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Post Options Post Options   Quote Contender 541 Quote  Post ReplyReply Direct Link To This Post Posted: 14 Aug 10 at 1:36pm

Originally posted by JimC

[QUOTE=Contender 541] General rule - IMHO - if the pole is on the forestay, the spinny is doing bugger all but making your day difficult

That's, shall we say, a very suprising rule of thumb and not one I could recommend...QUOTE]

Basic law of physics is that if the force of attack is at 90 degrees to the direction of motion, then it is *theoretically* doing nothing but pushing - in this case - the boat over or sliding it downhill.

It is for this reason that in the 5oh I can be 3 sail flat wiring in only 5 knots (and I do not dissapear when I turn sideways I can promise you)

The cut of the spinnaker can and does have huge influence on just how tight you can go, but to quote myself with one emphasis - as a General rule when the pole is on the forestay.......  Perhaps I should have added hard (on the forestay)

When you find a big kettle of crazy it's probably best not to stir it - Pointy Haired Boss

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JimC View Drop Down
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 14 Aug 10 at 5:30pm
Originally posted by Contender 541

Basic law of physics is that if the force of attack is at 90 degrees to the direction of motion, then it is *theoretically* doing nothing but pushing - in this case - the boat over or sliding it downhill.

There are a couple of small flaws in your theorising: firstly the sheet is not on the centreline of the boat and secondly the clew is not sheeted to a point exactly symmettrical around the mast to the tack. Only if both those were true would your theory stand up.

[later]Here's a nice shot of a pole kite boat at speed with the pole on the forestay... As you can see the pole is smack on the centreline and the clew is about a foot and a half off and there's no shortage of drive...
http://www.youtube.com/watch?v=9dM2V8OaxE0

Edited by JimC
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Garry View Drop Down
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Post Options Post Options   Quote Garry Quote  Post ReplyReply Direct Link To This Post Posted: 14 Aug 10 at 9:48pm
Try pole higher (quiet a lot compared to some other boats)
and twinner on a bit.
Garry

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Post Options Post Options   Quote RS400atC Quote  Post ReplyReply Direct Link To This Post Posted: 15 Aug 10 at 11:38pm

I think it's hard to formulate exact rules. Time  on the water is the only aid to judgement.

Sometimes, when the wind is not steady, the kite will be doing you no good 80% of the time, maybe even slowing you marginally. But the other 20% of the time, the kite helps enough that the overall gain is significant. So tough out the 80%, if you're convinced about the 20%.

Go for speed mostly, and be confident that you can drop the kite on a reach without stopping dead, i.e with the helm hiking hard and the crew not to leeward. Aim to sort your boat handling so changes of plan can be taken in your stride rather than looking like a fight between helm, crew and boat.

Sometimes it pays to ride the gusts for speed, then two sail to the mark. Other times you are better off going high early and arrivng at the mark in good shape for the next leg. Will a burst of speed get you clear air and tactical space, or get you into the lee of other boats?

If in doubt go high early, then set the kite.

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Post Options Post Options   Quote Paramedic Quote  Post ReplyReply Direct Link To This Post Posted: 29 Aug 10 at 9:17pm

I never let the pole touch the forestay. It's something i'm passionate about. I'd rather bear off, drop early and climb up to the mark or just get the kite down as it's too tight anyway.

If the pole is touching the forestay all it's doing is making you work hard for no real gain. Bear off and go fast, cover ground.

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Post Options Post Options   Quote zippyRN Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep 10 at 7:46pm
i t's going to be different for each class ( or even design / extent the tolerances have been played with ) 

it';s also going to depend on the cut of the spin 

from my recollections fireball kites do seem quite flat  much more of a 'reacher' than some of the kites you'll see for a GP or wayfarer which are shrunken yacht kites ...  if the spin you have on the boat is a 'running' cut  then  the point at which a two sail reach pays off will be further off the wind 

and the exact geometry of the rig ( hoist height , is the kite halyard putting the hoist point ahead of the leading edge of the mast to any degree , also how high you hoist , the exact length of the pole and the height of the pole / mast interface 


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Post Options Post Options   Quote Medway Maniac Quote  Post ReplyReply Direct Link To This Post Posted: 08 Sep 10 at 9:43am
The request was for a rule of thumb that could be used before hoisting. In both the Fireball and Wayfarer, I found that if the apparent wind was much ahead of the beam while two-sailing, it was unlikely that the kite would bring any extra speed if the wind remained steady.
 
But, the wind has a habit of moving about, so often it's worth pushing your luck a bit and going for the kite even if using it efficiently means falling off below the rumb line then dropping later. Often you'll get a lift and make it anyway.
 
As to when the kite is paying, I've been passed by plenty of people whose pole has been on the forestay (OK, not actually deflecting the jib luff) when i've not hoisted. Much more significant is how hard the crew is pulling on the sheet - if it's got to the point where it's just tightening the leach and causing more backwinding of the main, it's not quick.
 
[All the more surprising to me, then, to find that the latest 3000 kite can be used with benefit almost on a beat!]
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Post Options Post Options   Quote redback Quote  Post ReplyReply Direct Link To This Post Posted: 16 Nov 10 at 4:46pm
As a rule of thumb.  If the next leg is tight - go high, and if its free - go low.  So as for the kite - if its tight you should be 2 sailing until you are sure you can hoist and go down to the mark.  This has the advantage that you sail over all those boats that put the kite up and are now struggling.  If its very free to the next mark of course you will have the kite up and you "only" have to protect your wind.

Or to put it another way - if it looks tight wait and see.
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Post Options Post Options   Quote Phil eltringham Quote  Post ReplyReply Direct Link To This Post Posted: 17 Nov 10 at 11:25am

Only just caught up with this thread.  Granted its all calss specific but for nothing more thanthe sake of wading in because i can...

I seem to remember the 420s saying a reach was too tight if once you've got the pole on the forestay and the halyard eased a few inches that if the trailing edge of the kite was pointing infront of the transom then it was too tight. 
 
I know assys are a little different, but a 14 friend of mine's approach to tight reaching was hoist first if there was even a chance you could hold it.  You can always drop and come into the mark hot, and with rights if not clear ahead compared the guys that went high first, especially if you had pressure. Its far easier to judge the best angle to two-sail on when you have the mark closer and to aim at rather than guess at the start of the leg.  The caviat with that is knowing when it is too tight and not forcing the issue to far. 
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Garry View Drop Down
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Post Options Post Options   Quote Garry Quote  Post ReplyReply Direct Link To This Post Posted: 17 Nov 10 at 1:58pm
to go low or high at the start or end of a leg surely depends on 6 things:

1. Other boats around you
2. Your spinnaker handling skills
3. How far you need to bear away to hoist / drop in that wind strength
4 wind bend
5 size of the gusts
6 the next leg
Garry

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