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 Post subject: Lee board proposition
PostPosted: Sun Aug 11, 2013 12:32 pm 
Brotherhood of the Golden Paddle

Joined: Sun Aug 16, 2009 10:05 pm
Posts: 1427
Location: South Salem, NY
I don't know if this is possible, but there's a CNC guy not too far from me that can make just about anything out of plywood if you give him a good description or drawing. My thought is to get a sheet of good marine ply about 1" thick and have him knock out a bunch of 4' long lee boards. We could probably get 11 lee boards out of the sheet if we do them 8 inches wide - or maybe six inches wide? 48 inches might be too long as well. All open for discussion...

Maybe put a handle on top (shortening the dip...), with an airfoil and nice rounded bottom - have the mounting hole cut specifically for the Kayaksailor. It's possible we could even figure out a way to work the KS lee board handles into the fold and do without the alternative handle.

It's possible one long lee board could forgo the need for double boards with the KS. You could mount it on the Starboard side Frank since you already turn so well to the port. Ha. Glad you're still sailing.

Any thoughts? These could be made really cleanly and I'm guessing a few coats of varnish or epoxy would make them quite durable and possibly solve the high peak/short dip we are all experiencing with the stock model.

If there's enough interest I'll check on pricing. It's not worth my while to buy a sheet of marine ply and have him cut one lee board.

Lemme know.

d

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PostPosted: Sun Aug 11, 2013 2:23 pm 
lord high faltbotmeister

Joined: Thu Sep 06, 2007 8:05 am
Posts: 872
Location: atlanta, georgia
That is a great idea, I'm "in" for a pair! And welcome back Dennis.
Greg

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"There is nothing--absolutely nothing--half so much worth doing as simply messing around in boats"

1988 A1 Expedition
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BSD sail rig, 24' mizzen + 36' main
39' jib
Torqeedo outboard
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PostPosted: Sun Aug 11, 2013 7:00 pm 
Brotherhood of the Golden Paddle

Joined: Mon Apr 18, 2005 3:40 pm
Posts: 1146
Location: isles of scilly UK
I was out to-day using my long lee board on the Yukon with the 1.4 Kayaksailor sail(no jib) and it works well, (untill a heavy thunderstorm hit) i could get at least 40 degrees or better into the wind, but i must point out a lot more weight and stress is placed on the kayaksailor cross tube. If i remember correct it is about 43 inches from the pivot point (cross tube) to the bottom of the lee board.


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PostPosted: Sun Aug 11, 2013 10:05 pm 
Hey count me in. Please let me know details about the size you decide on and the cost. I would be interested in 2.


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PostPosted: Mon Aug 12, 2013 12:16 am 
BTW, D how long would it take to have the finished blanks made? I use the Knepper America mount so I may need a bit longer leeboards. I would like 2 and being able to control them with the leeward rods would make it easy. Being heavier will the rods work as well? My wife says the regular position of the rods make paddling more difficult. What other control system did you have in mind? If it helps I can sand & varnish them. The plywood layers would look great and if the wood is close in color to the wood on the LH it would be such a great combination. Thanks for the heads up.


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PostPosted: Mon Aug 12, 2013 7:24 pm 
Brotherhood of the Golden Paddle

Joined: Mon Apr 18, 2005 3:40 pm
Posts: 1146
Location: isles of scilly UK
As you all know i have two long lee boards one for the Klepper rig and one for the Kayaksailor. I control both the same way with a line to hole in the top of the lee board and to a hole in the bottom. With this i can raise the lee board, or have it at any angle, i think that going up wind is helped if the board is "raked" forward with the Kayaksailor rig.


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PostPosted: Mon Aug 12, 2013 11:25 pm 
I'm not sure I want a line in the water to control one motion of the leeboard, if I understand your description correctly, the line in the water would seem to be added drag. I do agree the leeboard pushed a bit forward seems to help keeping closer to the wind without having to use as much rudder. I am looking forward to a bigger set of leeboards for my bigger kayak. If Dave at Kuvia made bigger leeboards as an option I would have bought them. That is with 20/20 hindsight but they were not available anyway.

If there is a handle on the top of the leeboard like the Balogh leeboard can the forward person reach it on the KS rig? The KS rods work well but I do think there needs to be a more solid attachment rather than the plastic tubing there now. I have over tightened the leeboard knobs before and my wife was unable to move the leeboards. Another time I didn't tighten the knobs enough and their weight made them fall straight down.

D. do you think they could be ready within a few weeks or will it take longer? Still looking for a cost too.


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PostPosted: Tue Aug 13, 2013 8:07 pm 
Brotherhood of the Golden Paddle

Joined: Mon Apr 18, 2005 3:40 pm
Posts: 1146
Location: isles of scilly UK
Yes of course a line in the water will add a little drag. A front seat member of the crew would most likly be able to control the lee board but i sail from the back and a line to control the board was the easiest solution for me. Dave at Kayaksailor is aware that a longer lee board for our fold-ups would be a good thing but the cost of producing them would be too high for what is really a very limited market so we can make our own. Another thing that may help is a stronger cross tube, i havn,t looked into it to see if it is really needed. This week weather permitting i will be taking the Klepper out with the 1.6 sail plus the jib but the mount i have makes the cross tube absolutely solid and ridgid. For the Folbot Yukon i am now attempting to improve the rudder. Just thinking about the front crew member reaching the lee board, my Folbot Yukon is of course a single seater and i can just reach the "goal posts" but not the lee board so perhaps the front member wont be able to control the lee board, something you will have to experiment with.


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PostPosted: Tue Aug 13, 2013 9:36 pm 
Cool idea! Sadly, I do not need.

Could you glue up two halves of a 1/2" sheet and do a smaller run?


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PostPosted: Wed Aug 14, 2013 9:58 pm 
Brotherhood of the Golden Paddle

Joined: Sun Aug 16, 2009 10:05 pm
Posts: 1427
Location: South Salem, NY
Once we have an idea about what we want I can give them a call and get some rough figures on price and at least see if this is even worthwhile.

I think Birch would be nice but it may be possible that we could do it in some sort of plastic which might mean we can make them thinner. I'm also thinking 1" might be a little too thick, pricey and I even wonder if it's available. Any thoughts on material?

I think the KS boards are 4" wide. How wide should be go?

Does anyone know CAD drawing? Google Sketchup is as close as I've gotten to CAD. It's fun but not easy. Fortunately this is a simple design. If the CNC guy designs it the cost goes up.

John you've the most experience with material and length what do you think of 3/4"? BTW, are you interested in joining this venture?

It sounds like most of us want two; so a simple airfoil with one side flat should work. I believe the design is to have the flat side facing out so the airfoil 'flies' the board in towards the hull.

If there are only a three of us we can use the balance of the wood to make deck boards or whatever else we come up with. It's just a matter of design.

Heavy Weather's idea of gluing/epoxying two 1/2 inch boards together is interesting as well - this would mean we'd have a symmetrical airfoil though - which is what the KS has. I think 1/2" or 12mm is closer to the deck board size Mark at Long Haul uses. The downside is that we would have to glue them at home. Not the end of the world as they need to be finished anyway. 1" thick should be pretty sturdy... maybe too sturdy. Thickness is probably the biggest question right now.

Anyway, a few considerations before I call the man. I'll check the size on my deck boards and my 'flimsy' lee board tomorrow.

Anyway, some thoughts with numbers would be appreciated. Frank I think once we get the basic board configured we can decide if we should put a handle on it. The line system can always be added later and doesn't necessarily have to be dipping in the water - remember how high the KS crossbar is - a pulley forward of the crossbar could make the line system pretty convenient for pulling the board forward.

d

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Klepper Aerius II
Klepper T9
Long Haul MK1 Expedition 'light'
Klepper S4 sail rig
Kayaksailor 1.6 +genoa
BSD 36HP


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PostPosted: Thu Aug 15, 2013 12:15 am 
Brotherhood of the Golden Paddle

Joined: Mon Apr 18, 2005 3:40 pm
Posts: 1146
Location: isles of scilly UK
I have said somewhere, but i will go through it again. When i first made the long board for the KS i glued two pieces of 3/16 ply together making it 3/8 thick. When i tried it a vibration or "fluttering" at high speed started and didn,t appear that it would stop. So i made the board thicker by gluing a piece of 3/8 ply to each side making it 1-1/8 thick, it now dosnt vibrate. It is sanded to a foil section and it appears to work. With a long board i have no idea about how thin it can be before this vibration starts. If these boards were made of a "plastic" material it would be nice to have the foil shape "machined" as grinding plastic at home may not be a good idea but then there is cost to consider. With out considerable R and D it might be tricky to come up with the required thickness. There could be i suppose some info on the internet. I know David who came up with the KS rig did a lot of research and experimentation to get a good lee board. At the moment i am not sure if i want to come in on purchasing any.


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PostPosted: Thu Aug 15, 2013 3:43 am 
knight of the folding kayak realm

Joined: Wed Oct 07, 2009 6:42 pm
Posts: 468
On size and thickness, you might try asking Dave Stubbs of Britain's Solway Dory and the Open Canoe Sailing Group. He produces lee boards (and sails) professionally and is pretty good at sharing information. You can search for those websites, or you could try asking here--I'm pretty sure they've discussed leeboard thickness and size before: http://www.songofthepaddle.co.uk/forum/ ... ing-Canoes
Must get to work now.
All the best,
Ian


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PostPosted: Thu Aug 15, 2013 8:59 am 
Brotherhood of the Golden Paddle

Joined: Sun Aug 16, 2009 10:05 pm
Posts: 1427
Location: South Salem, NY
Thanks John, I do remember you mentioning that before, and thanks Ian, I'll check those links out.

As a quick update, my flimsy whimsy lee board is 48 inches long and looks like I sanded it out of 8mm marine 5 ply, making it about 7mm thick. I'm taking the T9 to Cape May for the next few days with the KS. I'll let you know how whimsy works out if I get a chance to play with it.

Meanwhile the thickness of Long Haul's boards are 12mm and feel pretty darned solid at 9 ply. - the Klepper lee boards are just a little thinner at about 3/8 inch.

I'm liking the 12mm 9 ply .

d

_________________
Klepper Aerius II
Klepper T9
Long Haul MK1 Expedition 'light'
Klepper S4 sail rig
Kayaksailor 1.6 +genoa
BSD 36HP


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PostPosted: Thu Aug 15, 2013 11:14 am 
Brotherhood of the Golden Paddle

Joined: Mon Apr 18, 2005 3:40 pm
Posts: 1146
Location: isles of scilly UK
Klepper lee boards are quite thin, short and wide so vibrations dont occur. In Todd E Bradshaws book "Canoe Rig,The Essence and the Art" he goes into lee boards, of course for Canoes, for thickness he says 3/4 to 1-1/8 and he shows the foil shapes, but his lee boards are 9 inches wide, we are looking at narrow boards and this is probably why the vibrations occur if they are thin.I have made some boards based on the Klepper design but longer i should see how these perform with the KS rig. So much to do so little time.


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PostPosted: Sat Aug 17, 2013 4:31 pm 
I took this video and noticed the sideways flexing of the leeboards. D I think the idea of flying them into the boat is a good one. I would prefer wood, however, dense plastic works too. Do any leeboards have a bulbus bottom tip like some large ships do to better cut through the water?
http://www.youtube.com/watch?v=mEOiIKhT ... e=youtu.be


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