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Another breezy one - another spanking.

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mongrel View Drop Down
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Post Options Post Options   Quote mongrel Quote  Post ReplyReply Direct Link To This Post Posted: 02 Feb 14 at 8:08pm
Pulling the board up will definitely help, especially to stop stalling thru' tacks.
Try maxing the kicker upwind, it will flatten the sail and take some load out of the mainsheet, making it easier to play in gusts/lulls.
As far as I know, a lot of singlehanders tend to use lots of kicker (or mainsheet tension with travellers) in strong breeze upwind.  I think you really have to set up with a flat sail, and not worry too much about the leech, the mast should bend in the gusts to relax the leech.
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 02 Feb 14 at 8:19pm
You want plenty of kicker to make the mid leech stand up because of the load through the battens/cloth so you can point, even if you ease the sail a bit, and you want loads and loads and loads of downhaul to flatten the top and slacken the upper leach so the top twists off in spite of all the kicker. And you just have to keep it flat, don't let it get anywhere near on its ear. Keep that mainsheet moving moving moving.
And yes, board up a bit will help some. You can leave it just a tad up for the whole race in those conditions, you'll just need to be more positive in the tacks.
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sargesail View Drop Down
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Post Options Post Options   Quote sargesail Quote  Post ReplyReply Direct Link To This Post Posted: 02 Feb 14 at 9:06pm
Originally posted by Rupert

I got stuffed upwind by the EPS again today! Looked pretty damn good to me. With lots of fetches (the first race, believe it or not only had 5 manouvers per lap. 1 gybe, one tack, 2 bear aways and a luff up. 

That's a Whitefriars course the way I remember 'em!
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Post Options Post Options   Quote sargesail Quote  Post ReplyReply Direct Link To This Post Posted: 02 Feb 14 at 9:36pm
Originally posted by iGRF

b**locks, I got it round and a few younger and more experienced didn't, I just didn't win and instead came last on handicap.

I had maxed the downhaul, but free'd it off the sail just wasn't driving, but I didn't max the kicker, why do that? It tightens the leech when i want the leech free to twist off and dump power don't I?

I must admit I don't mess with the board, it's a bitch to pull up anyway and I've got this hose pipe thing fashioned to act as a traveller to keep all the gubbins ahead of the mainsheet pulley and cleat and it's over the top of the daggerboard.

Ref Kicker:

I'll try and start at home, on your windsurfer, where you don't have a kicker.  So you crudely (and I may be a litttle out of date having not put a modern board rig together for a while - but if I'm out of date then just cast your mind back a few years) have two ways of flattening (aka depowering) the sail, once it's on the mast (but noting that your rig does not need to be as tuneable because of the many sails of different sizes you have in your quiver (thus ensuring that you can always have the wrong one on!):

An outhaul - which reduces the distance between the boom end and the clew, taking curve (though there may not be much anyway) out of the sail on the widest bit of it.  We'll ignore this in comparative terms since the function of the control is the same.

A downhaul - on your board sail this has two effects when you tighten it:

It pulls the 'spare' cloth in your laminate sail forward, and downwards.
It also, through that cloth (and because there isn't spare this is a major effect) compresses the mast in to a curve which again pulls spare cloth forward, thus flattening the sail in general.  As an associated effect the upper leech of the sail is opened, principally because the movement of the mast tip back and down in compression creates 'spare' cloth in that top bit.

Now to your EPS.  Which has but one rig and therefore must be tuneable to a wider range of conditions, by stretching the sails or by bending the mast.  

The downhaul now works in a subtely different way.  In the days of dacron (and even more so with cotton, as the wind increased the 'spare' cloth (which did exist) would be blown backwards, creating a very draggy sail with a tendency to generate weather helm since the power was all in the back.  The downhaul was used to control this effect.  In harder mylar (tho some older ones will need downhaul to correct the stretch) sails it is used to flatten the sail by artificially reducing the luff length and therefore making a mast 'absorb' more of it's spare luff (aka luff curve) for a given amount of mast bend.  But it does not (except in a few classes) actively bend the mast in the way that the windsurfer downhaul does.  However it does open the upper leech, but not to the same extent.

So what bends the mast:

The kicker.  Pull it on until you're in control.  Your leech, as you say, will be tight with the potential to create some weather helm, but you can counteract this by pulling the spare cloth forward again - with the downhaul.  It that doesn't work then I'm afraid it's time to heel the boat to windward, or get that board up a bit.

What happens if you don't pull the kicker on (This may seem familiar):

Your arms have to work hard because every time you sheet in to any decent amount you'll be doing the hard work of pulling on the leech without teh help of that massive purchase from the kicker.

Power and weather helm will be binary.  The leech will not start working gradually as you sheet in and change its angle across the boat, but will kick in with a bang when you pull the boom downwards.  And you'll screw into wind.

This effect will be particularly bad at slow speeds and in to and out of the tack.  Especially as there will be no power in the leach to help you tack.

And when you do have to point too high because you way as much as one of those pink wafer sandwich biscuits (with a bite taken out) you won't have a leach to help you maintain height.

LOADS OF KICKER go on try it!
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iGRF View Drop Down
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Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 02 Feb 14 at 9:53pm
OK, best explanation yet.. Thanks, that was exactly what was happening and things only improved a bit once i banged some kicker on, but by then the wind had moderated back to a 4-5.

As to Windsurfers, we have the additional ability to cant the rig further to weather and our rig twist is entirely determined by luff tension, with of course inducers holding foil stability.


PS I didn't notice the 300 on the water today.
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Post Options Post Options   Quote Lukepiewalker Quote  Post ReplyReply Direct Link To This Post Posted: 02 Feb 14 at 9:54pm
The only time you want no kicker for open leach wind dumping is in perfect storm survival conditions...
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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 03 Feb 14 at 9:56am
Yup, the only reason to let the kicker off is for the same reason you do when you get to the shore - to stop the boat falling over when totally overpowered.

As sarge says, kicker and cunningham work in tandem. My advice to junior Laser sailors in survival weather is to pull the cunningham on until you can't pull any more on, then pull some more on anyway...

No wonder Laser sails wear out so quick. At leat the EPS has a sail that can be dealt with somewhat more subtly. But it will still need feet braced to pull enough cunningham on.
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Post Options Post Options   Quote fab100 Quote  Post ReplyReply Direct Link To This Post Posted: 04 Feb 14 at 8:40am
Sure sound like insufficient kicker is your main problem

Further to Sargesails great analysis, one further thought comparing dinghy mainsails to board sails...imagine if your board sail had no material below the wishbone. How hard do you think you would have to pull the wishbone down to achieve a desired leech and general sail shape? Surely that bottom bit of sail material acts rather like a ton of kicker does on a dinghy sail

General rule then. If you are struggling with too much power upwind, pull the strings harder, harder and harder; kicker, cunno and out haul. Bend the mast and, if you can, rake it back. If you have to ease the kicker during tacks in order to get under the boom, then so be it.

Do this right and you can reduce the power generated by a sail to a small fraction of what it was and life suddenly seems a lot less of a struggle


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Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 04 Feb 14 at 9:02am
Many moons ago, before the advent of full batten and cam race sails I experimented with a kicker (and a topping lift) on a sailboard race rig, it did nothing to improve performance, in fact quite the contrary, so I guess my reluctance to fully accept it's features and benefits is because of that, that and the Alto with it's rear sheeting seems to be less kicker reliant (got my best open mtg result racing round that island without one)and I can't say I used it much with the 500.

I also seem to end up with Gnav's which don't do the job in the same way as a proper kicker, bend the mast horribly, distort the sail awfully and don't seem to have as much feedback as to when enough is enough.

Since I've been down the lake, I have been trying harder to do all that kicker on/off stuff and pull all manner of stupid rope, but, that EPS has the most silly controls that don't function well when the racks are set in the inboard position. I also have another issue in that ever since it blew off it's trailer one of the rack pin things has jammed, making it impossible to adjust the racks out which kind of compounds the problem when it's breezy, having to use them in their fully inboard position which is exactly counterproductive.

Like everything dinghy, there has to be a better way, I'd love to have gotten my hands on the C2 rig to see if that works any better.

Oh and ref windsurfing, we do have fixed sail size OD racing, I cut my teeth doing it, but sail cuts were permitted to evolve over the years and the classes that didn't died away, and we also had our equivalent of development classes around fixed sail sizes, very rarely did changing down do anything much more than keep you in the game and only really worked if everyone else downsized in stupid conditions.
I must buy a small sail though, just to see what if any difference it makes although I suspect only marginal improvement up wind and I'll lose all my rocket ship downwind performance where I can at least get back into the race. They love it when I suddenly appear as if from nowhere just inside them within three boat lengths of a mark rounding.

Edited by iGRF - 04 Feb 14 at 9:14am
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Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 04 Feb 14 at 9:23am
Originally posted by fab100

Surely that bottom bit of sail material acts rather like a ton of kicker does on a dinghy sail

You know what? You're absolutely right that is what happens, although it's kind of fixed rather than variable so the lower leech is always on, which isn't the case with a boat rig, so yes that's it, I've got it now.

That was why my crude boom vang attempts didn't work. Half the time I'm trying to logic what's going on in dinghies to what I used to reason back in the late seventies early eighties, because of the difference in rig development I've obviously been through but dinghies didn't (not saying either is right or wrong, just different)
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