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  #1  
Old 04-28-2009, 06:07 AM
fabrice fabrice is offline
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Join Date: Mar 2009
Rep: 10 Posts: 54
Location: Poitiers, France
kayak/canoe outrigger issue

While trying to fit an outrigger to my sea kayak, I ran into a major flaw :

First try : PVC pipe, 4 meters long, quite elegant while in the water, actually. Made it look like a water spider (a giant one )
BUT, PVC is heavy, leading to bad buoyancy factor (the pipe tends to sink as soon as I gain speed under sail)
and she's a pain in the ass to paddle, as she goes strongly over the outrigger side.
Second try : inflated buoys : even worse (lot of drag, turn, and clumsy look)

I'm concerned about the turning tendancy, as I want my kayak to be both paddled and sailed.

ethnic canoe hulls are sharp with rounded outriggers, sometimes just a log.
As my kayak hull is flat/round (more or less U shaped), should I design a sharp (V shaped or so) outrigger to help a straight route ?

thanks for your help !
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  #2  
Old 04-28-2009, 08:03 AM
Chris Ostlind Chris Ostlind is offline
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Fabrice,

Thanks to the fine work of Gary Dierking in New Zealand, you can build your own amas from simple materials. They are very nice looking, perform well and best of all you can build them at home with inexpensive stuff from the local home supply store.

http://homepages.paradise.net.nz/garyd/quikama.html
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kayak/canoe outrigger issue-quikama12.jpg  
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  #3  
Old 04-28-2009, 09:36 AM
fabrice fabrice is offline
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Location: Poitiers, France
chris, thanks for the answer.
Well, actually I already saw gary's pages.
I was just wondering if this design could fix my turning problem ?
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  #4  
Old 04-28-2009, 09:46 AM
Chris Ostlind Chris Ostlind is offline
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The ama could be factor in turning, depending on its length and shape, but I'd be much more inclined to ask the same questions of the kayak itself.

What kind of boat is it? (length beam, as well as general style)

What kind of bottom profile (rocker) does it exhibit?

What was your previous turning technique in the kayak before you affixed any outrigger setup?

Do you have a rudder for steering and if so, what size is it in the water?

Does the rudder have much flex? (does it bend-off to one side when you apply steering input?)

Maybe you have some photos, or drawings of the rig as you are using it at present?
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  #5  
Old 04-28-2009, 10:21 AM
fabrice fabrice is offline
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Location: Poitiers, France
sorry no pics by the moment.
The kayak is a rainbow laser : sea kayak with :
no rudder, 5,10 meters LOA, 0,6 m beam, hull flat U shaped with pointed and sharp bow and stern, not much rocker.

I'm not a begginer in kayak strokes, my forward stroke is rather straight and near the hull : no parasite turning.
My steering technique depends on goals and environnement, but I usually mix edging with circular strokes. works fine so far.
Plain classical kayak stuff I guess.
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  #6  
Old 05-28-2009, 02:49 PM
johnholland4 johnholland4 is offline
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Location: Toronto, Canada
Fabrice, I did something similar but with this difference. Using 4" pvc I converted my 20' Nick Schade double kayak into a trimaran, thus keeping it stable. I used 16' akas made of 4" by 1/2" ash and a mast and sail from my windsurfer. It goes like a bat and paddles easily. I'm in the process now of installing a daggerboard to give me more windward ability. Somehow the notion of an outrigger seems to me unbalanced, at least if you hope to achieve any kind of speed. Hope this helps. John.
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  #7  
Old 05-29-2009, 05:57 PM
Guest625101138 Guest625101138 is offline
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Quote:
Originally Posted by fabrice View Post
While trying to fit an outrigger to my sea kayak, I ran into a major flaw :

First try : PVC pipe, 4 meters long, quite elegant while in the water, actually. Made it look like a water spider (a giant one )
BUT, PVC is heavy, leading to bad buoyancy factor (the pipe tends to sink as soon as I gain speed under sail)
and she's a pain in the ass to paddle, as she goes strongly over the outrigger side.
Second try : inflated buoys : even worse (lot of drag, turn, and clumsy look)

I'm concerned about the turning tendancy, as I want my kayak to be both paddled and sailed.

ethnic canoe hulls are sharp with rounded outriggers, sometimes just a log.
As my kayak hull is flat/round (more or less U shaped), should I design a sharp (V shaped or so) outrigger to help a straight route ?

thanks for your help !
Fabrice
The simplest, lightest and fastest to build are carbon fibre over Corecell. You can make two quite buoyant outriggers that are 2.5m long and say 100 to 150mm out of a single sheet of Corecell and 5m long by 1m wide of 200gsm CF that will be light and strong.

I have 1.8m long outriggers built like this that weight just under 1kg each without the supporting tube. They have rectangular cross section, flat bottom and slight nose rocker so they lift to plane at speed.

They are made very simply with little marking out using flat pack method with 220gsm by 50mm wide glass tape as the joiner.

You should mount them so they are above the normal waterline thereby offering no drag when the boat is ballanced. They will provide up to 300N of uplift which should be ample to carry a decent sail on a kayak. I doubt that they will alter ability to turn.

I do not have a separate picture of one but you can see them on this boat:
http://www.boatdesign.net/gallery/sh...//ppuser/18624

Note I did not say cheapest above. The materials will set you back about USD400 depending on how well you can shop. They will be very nice though - incredibly stiff and strong, good looking (if you fair them out) and unbelievably light weight.

Rick W
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  #8  
Old 04-02-2010, 03:05 PM
fabrice fabrice is offline
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just for the record, if someone follows the same path :
I tried quickly with a sharp V shaped (foam core) and the kayak steered well, with very little drag on the ama.
Now the kayak is long sold and I'm thinking of building an outrigger canoe ...
so for what it's worth : to every kayaker, yes it's worth it !
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  #9  
Old 04-02-2010, 03:42 PM
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pogo pogo is offline
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Location: germany
Look at this:

http://multihull-parts.com/40974.html

pogo
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