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Kicker angle

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Post Options Post Options   Quote H2 Quote  Post ReplyReply Direct Link To This Post Topic: Kicker angle
    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!
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mozzy View Drop Down
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Post Options Post Options   Quote mozzy Quote  Post ReplyReply Direct Link To This Post 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.  





Edited by mozzy - 24 Nov 17 at 3:52pm
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Post Options Post Options   Quote mozzy Quote  Post ReplyReply Direct Link To This Post 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
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Post Options Post Options   Quote H2 Quote  Post ReplyReply Direct Link To This Post 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.
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Post Options Post Options   Quote H2 Quote  Post ReplyReply Direct Link To This Post 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

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??
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Post Options Post Options   Quote mozzy Quote  Post ReplyReply Direct Link To This Post 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!


Edited by mozzy - 24 Nov 17 at 3:50pm
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sawman View Drop Down
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Post Options Post Options   Quote sawman Quote  Post ReplyReply Direct Link To This Post 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,

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Post Options Post Options   Quote laser193713 Quote  Post ReplyReply Direct Link To This Post 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. 
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Post Options Post Options   Quote mozzy Quote  Post ReplyReply Direct Link To This Post 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. 


Edited by mozzy - 24 Nov 17 at 4:07pm
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Post Options Post Options   Quote mozzy Quote  Post ReplyReply Direct Link To This Post 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)? 


Edited by mozzy - 24 Nov 17 at 4:19pm
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