Lightweight Carbon Tube Folder

Discussion of user-built folding kayaks

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Ianh

Lightweight Carbon Tube Folder

Post by Ianh »

Hello everyone, this is a link to some pictures of a folding kayak I made. Explanation of most things is there with the pictures. My own design, many construction principles following Tom Yost, with variations as necessary due to the carbon tube stringers. All up weight 10kg

http://www.flickr.com/photos/50860028@N ... 87/detail/

Ian

ozarque

Re: Lightweight Carbon Tube Folder

Post by ozarque »

Fantastic job. How is the rigidity while paddling in chop?

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KayDubbya
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Posts: 61
Joined: Wed Apr 16, 2008 2:30 pm
Location: Kelowna, BC, Canada

Re: Lightweight Carbon Tube Folder

Post by KayDubbya »

Really clever design & build. I like the idea of the vertical support on the rear cross frame. With a zippered deck loading is easily done despite the cross frame. Let us know how well it rolls.
Feathercraft Wisper

Ianh

Re: Lightweight Carbon Tube Folder

Post by Ianh »

Thanks, the kayak is extremely rigid, more so than any other folder I have seen due to the combination of carbon tube and tensioning strings.

The carbon tubes are slightly larger diameter and quite a bit the stiffer than the standard 3/4 inch alu tube people generally use. (I just checked, they are about 75% stiffer than the standard 3/4 inch alu tube at nearly half the weight)

I went to the higher stiffness tubing as I wanted the option of using it for a later sailing kayak project, for which the rigidity will be more important.

I haven't tried rolling it yet - water in the local lake is very cold, I completed it at the end of last summer, so it will be a while before the water is warm enough to try in the lake.

I still have a little work to do to simplify assembly - sorting out the rest of the HDPE corner connectors for the ply cross frame-stringer connections, simplifying the tensioning strings down to I think three tapes that tension up with friction buckles.

I am working on a design for a bigger kayak, optimised very much for sailing performance - a bit like an International Sailing Canoe with perhaps a 6 square metre sail and the ability to hike out on a frame. The beauty of this way of putting a kayak together is that the stringers are all 4 metres long, and can be reused in a completely different design without changing their length or otherwise altering them.

I'm more focussed on building a sailing boat at the moment. http://www.storerboatplans.com/GIS/GISplan.html

I have 4 kids, so started to realise that even building a bigger kayak, it would be difficult getting them all in, and I'd be the only one paddling for a while, so a bigger boat with sail power seems the way to go for now.

Ian

jbohm

Re: Lightweight Carbon Tube Folder

Post by jbohm »

Hi Ian,
Kayak looks fantastic, any idea on how it's going lately?
Any more juicy pics
cheers

Ianh

Re: Lightweight Carbon Tube Folder

Post by Ianh »

Sorry, haven't been using it much, I've been building a Goat Island Skiff http://www.storerboatplans.com/GIS/GISplan.html, which is more what I need to get on the water with the family.

I'll get back to the folding kayak soon, I'm also thinking of a folding version of Dave Gentry's Ruth http://gentrycustomboats.com/RUTH%20page.html using some of the carbon tube I have plus the gunwales and keel done from some slightly larger diameter fibreglass tube. I think the standard cheap end of fibreglass paddle shaft material (OD about 28 mm) could work well for these designs. I haven't calculated strength and stiffness values yet, but I'm guessing it would be a little lighter and still stiffer than the 3/4 inch alu tube Tom Yost uses, and of course the big advantage is it won't corrode. Price seems good, with carbon you can of course get nearly twice the stiffness for half the weight, but at more than five times the price. Possibilities open up with a reasonable, non corroding material for stringers for a few hundred dollars a kayak rather than 1-2 thousand dollars for carbon stringers.

The other thing I'm after is some Desmoplan material http://tpe-u.com/tpu/emea/en/markets/sp ... Kajak.html for skinning, it seems ideal in terms of durability, ability to glue it reliably with the same heat activated urethane glue Tom Yost uses on PVC/Coverlene, but with good stretch characteristics to make getting a smooth skin easier. I may be on to a source of this material, but if anyone can follow up/chase this and get onto a source that would make it available for homebuilt folding kayaks, it would revolutionise building of same. It seems to be made by Bayer in Germany. I'll post if I get anywhere.

Ian

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