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Kicker angle

Printed From: Yachts and Yachting Online
Category: Dinghy classes
Forum Name: Technique
Forum Discription: 'How to' section for dinghy questions and answers
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=12921
Printed Date: 05 Jul 20 at 8:53pm
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Topic: Kicker angle
Posted By: H2
Subject: Kicker angle
Date Posted: 24 Nov 17 at 2:43pm
My boat has a very powerful kicker which is essential in setting up the large, fully battened, square headed mainsail. Due to the lack of lowers on my carbon mast the kicker when pulled on not only pulls the boom down but it also bends the lower mast which I would like to minimise.

Is there a way to alter the angle of the kicker by fitting some kind of rod set up  from the gooseneck so that the kicker pulls more downward on the boom rather than equally down and forward?

If anyone could steer me to what this is called or some pics that would be smashing!



Replies:
Posted By: Guests
Date Posted: 24 Nov 17 at 3:06pm
Do you mean the rod kickers like seen on OK and Finn's and some moth

These don't actually change the angle of pull, they just add a traditional lever in place of a block and pull cascade. They are still pulling the same two points together though to increase leech tension and bend the mast. 

Or do you mean a rod system like on a 29er / VXOne RS300, (gnav) where you pull a fixed length rod closer in to the mast? This in effect has a variable direction of pull on the kicker (actually 'push' from above) so it pushes more down and less forward as you increase kicker. 


Really, the only way to change how the kicker pulls down or forward is the change where it attaches to boom and mast foot (or deck).  In the 200 the kicker attaches to the boom can be slided closer or further from the gooseneck, and it make a huge difference to how the kicker effects sail shape.  





Posted By: Guests
Date Posted: 24 Nov 17 at 3:29pm
Actually, having just read this, the lever on a moth does change the angle of pull. 

See below

http://www.harken.co.uk/DeckLayout.aspx?id=15490" rel="nofollow - http://www.harken.co.uk/DeckLayout.aspx?id=15490


Posted By: H2
Date Posted: 24 Nov 17 at 3:33pm
Mozzy - I was chatting to a very good well known sailor who had taken the H2 for a blast and he made a passing comment that the kicker needs to pull down more rather than bend the mast. He suggested either moving the attachment on the boom in toward the mast or else (if the class rules allowed) setting up some way to change the kicker angle. He mentioned something that other development classes have been playing with that sounded a bit like a gnav but that worked with a traditional kicker instead of replacing it. If you imagine a rod attached to the boom at the goose neck at one end and at the other forced the existing kicker back and down so that when you pulled on the kicker the part from the boom would be pulling directly downward and the bit that came from the bottom of the mast would be parallel to the deck.


Posted By: H2
Date Posted: 24 Nov 17 at 3:37pm
Originally posted by mozzy

Actually, having just read this, the lever on a moth does change the angle of pull. 

See below

http://www.harken.co.uk/DeckLayout.aspx?id=15490" rel="nofollow - http://www.harken.co.uk/DeckLayout.aspx?id=15490

Yeah - I think that was what he was talking about but perhaps he was suggesting that the rod would be further forward on the boom and at a 45 degree angle??


Posted By: Guests
Date Posted: 24 Nov 17 at 3:47pm
Yes, simply moving the kicker attachment on the boom forward increases down force and reduces mast bend, but you also lose leverage. Adding a strut in there like the Moths create the desired effect but increases leverage. 

Looking at the moths all you'd need would be a 'strut' and piece of dynema that goes from the strut to the existing fitting for the kicker on your boom. The attach you current cascade kicker to the strut. How you fix the strut end to the boom may be an issue and whether the boom can take those loads is another issue. 


If it's in the class rules give it a shot and report back!


Posted By: sawman
Date Posted: 24 Nov 17 at 3:54pm
some scorpions have a "prodder" kicker - to resolve this issue - a horizontal bar from the bottom of the mast (its deck stepped) the purchase system runs from the end of the rod up to the boom,  I think P&B sell the bits,



Posted By: laser193713
Date Posted: 24 Nov 17 at 4:01pm
Originally posted by mozzy

Do you mean the rod kickers like seen on OK and Finn's and some moth

These don't actually change the angle of pull, they just add a traditional lever in place of a block and pull cascade. They are still pulling the same two points together though to increase leech tension and bend the mast. 

Or do you mean a rod system like on a 29er / VXOne RS300, (gnav) where you pull a fixed length rod closer in to the mast? This in effect has a variable direction of pull on the kicker (actually 'push' from above) so it pushes more down and less forward as you increase kicker. 


Really, the only way to change how the kicker pulls down or forward is the change where it attaches to boom and mast foot (or deck).  In the 200 the kicker attaches to the boom can be slided closer or further from the gooseneck, and it make a huge difference to how the kicker effects sail shape.  




The upside down kicker, or gnav will actually increase the mast bend from a given kicker tension. That is why boats with these almost always have a second set of lowers just above the gooseneck to limit mast bend, just like in your picture.

The actual answer to the issue H2 is having is to cut the sail with more luff curve to suit the mast. 


Posted By: Guests
Date Posted: 24 Nov 17 at 4:02pm
I see. However, with the scorp system it pull the boom down toward a prodder bar which is fixed (but pivots on same axis as boom). It's essentially the same as the moth, but upside down. 

Originally posted by craiggo

Graeme, get rid of the hoop, as you say if you have a bridled mainsheet onto the transom which is then led along the boom and down into the cockpit there is no need for a hoop. 

Regarding the scorpion kickers system I mentioned previously I cant find any photos but here is a sketch (sorry for the lack of artistry its an MS Paint special), effectively a temple vang mounted from the foredeck rather than the boom. wire from prodder to cockpit sole/bulkhead junction ensures that prodder sees no bending only compression. THe prodder is only pinned to the back of the foredeck to allow it to rotate laterally with the boom. 
http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=4639&PN=3&title=gnav-vs-kicker" rel="nofollow - http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=4639&PN=3&title=gnav-vs-kicker


Posted By: Guests
Date Posted: 24 Nov 17 at 4:13pm
Originally posted by laser193713

The upside down kicker, or gnav will actually increase the mast bend from a given kicker tension. That is why boats with these almost always have a second set of lowers just above the gooseneck to limit mast bend, just like in your picture.

The actual answer to the issue H2 is having is to cut the sail with more luff curve to suit the mast. 

Yeah, I wasn't suggesting those systems would solve his problem, I was just posting pictures to try and understand what system he was referring too... turn out none of the above, he was refering to the prodder system on the moth and scorpion. 

I can see the point of the prodder on the moth where the boom is too low to get an effective kicker angle. But the scorpion they are changing the kicker angle from what would be fairly normal, to one that pulls vertically down. Why don't the scorpion just use more main-sheet tension if that's their aim (and move the traveller to change sheeting angle)? 


Posted By: Jack Sparrow
Date Posted: 24 Nov 17 at 4:28pm
Temple vang, if you have enough room?

http://www.yachtsandyachting.com/photos/forum/JackSparrow/2008-09-11_142115_DSCF0105.JPG


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Posted By: davidyacht
Date Posted: 24 Nov 17 at 10:58pm
I think that Taxi had a system on his Solo with a bar to the mast gate, so that the kicker pulls straight down ... might be worth talking to him.

Or you could talk to Dougal who probably has photos of Barry Dunningís system on the Merlin ďSubstituteĒ.

However you may find that the mast could be bending because of leech tension and downhaul tension, not just due to the thrust of the kicker ... which is why even if I donít use any kicker on my Solo I can achieve much the same effect by dropping the traveller down and playing the mainsheet.





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Happily living in the past


Posted By: Neptune
Date Posted: 25 Nov 17 at 10:30am
Or go sail a 300 and embrace the whole effect 😀

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RS300 and RS200, ex Musto Skiff


Posted By: ColPrice2002
Date Posted: 25 Nov 17 at 10:08pm
Going back in technology, can you add a mast ram?

Our old Merlin had an alloy rod from the foredeck to the front of the mast at gooseneck height. This pivoted below the foredeck and had a pulley system for adjustment.

Other than that, could you add a dyneema set of lowers?

Colin


Posted By: Sam.Spoons
Date Posted: 25 Nov 17 at 10:29pm
I think the H2 Class rules preclude such remedies, certainly lowers are prohibited, mast struts are not specifically allowed which suggests they too are prohibited (and a mast ram, as such, is not appropriate for a deck stepped mast).

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Spice 346 "Flat Broke"
Blaze 671 "supersonic soap dish"


Posted By: Presuming Ed
Date Posted: 26 Nov 17 at 12:03pm
Do what Scorpions - who have the same issue do?

http://forums.sailinganarchy.com/uploads/monthly_03_2007/post-419-1172968565.jpg" rel="nofollow - http://forums.sailinganarchy.com/uploads/monthly_03_2007/post-419-1172968565.jpg ">




Posted By: 423zero
Date Posted: 26 Nov 17 at 12:43pm
What about a leech tensioner similar to downhaul, but pulling down from end of boom control line fed along boom with outhaul.


Posted By: Do Different
Date Posted: 26 Nov 17 at 3:27pm
I assume full centre main, by which mean mainsheet is not only controlled from mid boat but also has multiple purchase to the centre of the boom with nothing to the transom. 

If so how about "helping out" the kicker by using mainsheet tension to control leech tension and have a traveller, either track or rope so that leech tension is still maintained "little or much" depending on the precise arrangement even when the boom is eased out to well out over the quarter.

edit. now noticed, sorry Davidyacht a variation on what you said. As ever in sail controls hardly ever does one control work in isolation or only have one effect. 


Posted By: davidyacht
Date Posted: 26 Nov 17 at 4:13pm
The potential issue with the H2 set up is that the boom is cranked high and at an angle, so the mainsheet/traveller arrangement is not particularly precise, so I can understand why isolating the kicker to control the leech tension and using the sheet to open and close the barn door makes some sense.

I assume that the benefit of this arrangement is that there is less head banging.

It would be interesting to hear Keithís interpretation of the class rules as to what is and is not allowed, for instance I cannot quite see where lowers are disallowed, or what different kicker arrangements are legal.


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Happily living in the past


Posted By: Wiclif
Date Posted: 26 Nov 17 at 6:23pm
I wonder if the answer is for your spreaders to be angled forward, perhaps up to 50mm ahead of the stays in a neutral position, with a tight forestay in the medium conditions. And letting it off as the wind comes up? I think an adjustable forestay is one of your controls?

Only answer is to try it and see, and report back!


Posted By: H2
Date Posted: 27 Nov 17 at 9:50am
Originally posted by ColPrice2002

Going back in technology, can you add a mast ram?

Our old Merlin had an alloy rod from the foredeck to the front of the mast at gooseneck height. This pivoted below the foredeck and had a pulley system for adjustment.

Other than that, could you add a dyneema set of lowers?

Colin

Thanks Colin - rams and lowers not allowed


Posted By: H2
Date Posted: 27 Nov 17 at 9:52am
Originally posted by Wiclif

I wonder if the answer is for your spreaders to be angled forward, perhaps up to 50mm ahead of the stays in a neutral position, with a tight forestay in the medium conditions. And letting it off as the wind comes up? I think an adjustable forestay is one of your controls?

Only answer is to try it and see, and report back!

Yes was planning to try this next!


Posted By: Ian99
Date Posted: 28 Nov 17 at 11:02am
Given how new the class is, I'd go in with proposing a rule change to allow fixed lower shrouds.
It sounds like the rig needs them, all options of kicker will still bend the mast at the gooseneck if it's not supported or the mast made stiffer.


Posted By: JimC
Date Posted: 28 Nov 17 at 11:26am
I would find it very hard to design a modern style gust responsive rig with no gooseneck level control. I think for a boat with such restrictions I'd have to be thinking about a very expensive custom mast which was heavily beefed up at least to the spreaders in order that there wasn't mast bend where its not wanted. As I understand things as soon as you start using the spreaders to push the mid mast back then the gust response goes to hell, and the boat gets a lot less pleasant to sail. With my IC I found that if I put the spreaders forward to add power, the resulting handling characteristics deteriorated to such an extent that it was faster to put the spreaders back and accept the reduced power.


Posted By: sargesail
Date Posted: 28 Nov 17 at 12:40pm
Originally posted by JimC

I would find it very hard to design a modern style gust responsive rig with no gooseneck level control. I think for a boat with such restrictions I'd have to be thinking about a very expensive custom mast which was heavily beefed up at least to the spreaders in order that there wasn't mast bend where its not wanted. As I understand things as soon as you start using the spreaders to push the mid mast back then the gust response goes to hell, and the boat gets a lot less pleasant to sail. With my IC I found that if I put the spreaders forward to add power, the resulting handling characteristics deteriorated to such an extent that it was faster to put the spreaders back and accept the reduced power.

Yes even with something as low tech as the 2000, I reached the point of catastrophic boat speed and handling loss when I went just that little bit too far.  At neutral and a tiny bit forward all OK.  One hole more and it was horrible).


Posted By: zippyRN
Date Posted: 28 Nov 17 at 12:45pm
Originally posted by JimC

I would find it very hard to design a modern style gust responsive rig with no gooseneck level control. I think for a boat with such restrictions I'd have to be thinking about a very expensive custom mast which was heavily beefed up at least to the spreaders in order that there wasn't mast bend where its not wanted. As I understand things as soon as you start using the spreaders to push the mid mast back then the gust response goes to hell, and the boat gets a lot less pleasant to sail. With my IC I found that if I put the spreaders forward to add power, the resulting handling characteristics deteriorated to such an extent that it was faster to put the spreaders back and accept the reduced power.

you could do that with carbon  or  with an internal sleeve , i'm not sure how far up the mast the sleeves that   were put into proctor Ds  were  pre  D+  section  went 


Posted By: Presuming Ed
Date Posted: 28 Nov 17 at 2:04pm
Assuming the OP sails a Hadron H2, isnít it a little odd that rig issues like this werenít sorted at prototype stage?


Posted By: iGRF
Date Posted: 28 Nov 17 at 2:20pm
I haven't yet sailed this boat, but I'd be very wary of boatpark advice like that.

Is it not, what do you call it 'hog stepped', as stupid a term as ever there were, the mast on the deck and the kicker appears to be lead lower anyway. The Boom isn't exactly half way up the mast either, so I can't see any liklihood of massive distortion of the lower half of the sail.

Plus, again, I don't know any of this, but it's been built recently so I'd imagine the luff curve of the sail is matched to perform with a bent mast and very often that mast bend assists in gust response if any of the lessons we've learned in windsurfing have jumped the gap which they must have by now.

So until you hear from some of those connected with it's design and production I'd hesitate in a) criticism and b) adding on crap that isn't needed like lowers, they get in the bloody way of everything.

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Posted By: JimC
Date Posted: 28 Nov 17 at 2:22pm
Well, not everyone has the same ideas about what's good in rigs. There are loads of classes with what I would regard as inadequate lower mast control and excessive low down mast bend that their owners are perfect satisfied with sailing.


Posted By: Guests
Date Posted: 28 Nov 17 at 2:42pm
It all depends on what you've learnt sail controls to do. In all the boats I've sailed the kicker has been used to depower the sail and the main sheet has been used to hold leech tension. I a couple of classes you've got a traveller to hold the same leech tension off centre too.  Up wind if the boom is off the centre line I really want the sail depowered, so I'm very rarely looking for a tighter leech in a situation where I can't achieve it with more main. 

Additionally, with a jib, plus a kite, when the main is off centre I actually want the boom to lift to create more twist as the bottom of the sail needs to be sheeted significantly closer than the top (especially true in the 200 where you have a significant amount of main with no spinnaker to prebend the wind) . 

I can see a situation when close reaching in a single sail boat where you'd want more power with the boom out past the extent of the traveller (where you can do the same with main tension). 


Posted By: davidyacht
Date Posted: 28 Nov 17 at 4:24pm
Originally posted by Presuming Ed

Assuming the OP sails a Hadron H2, isnít it a little odd that rig issues like this werenít sorted at prototype stage?

The OP might be wrong ...


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Happily living in the past


Posted By: jeffers
Date Posted: 28 Nov 17 at 5:01pm
Originally posted by davidyacht

Originally posted by Presuming Ed

Assuming the OP sails a Hadron H2, isnít it a little odd that rig issues like this werenít sorted at prototype stage?

The OP might be wrong ...

Given the people involved with developing the H2 I find it surprising that they would have missed something obvious like this (or gone down a different route). Certainly my chat with Keith when he bought them to Hunts was that he paid a lot of attention to the rig as well as the hull form so it is likely it was designed around not having lowers or a ram....


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Paul
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D-Zero GBR 74



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