Kayak Design

[mut]

Hi guys,

Let me preface this by saying I have no experiance in building boats, but i am a joiner, so have most of the nessesary tools. I also have access to a CNC router.

I want to build a kayak, for canals and calm rivers, after some reasearch, i think the stich and glue technique is best for me.
I have been lookin around on the internet, and found a few ready to cut dxf files for canoes, but cant seem to find any for kayaks.

So my question is, does anyone know of any good resources where i can litterally download/buy a full size DXF plan of a suitable kayak?

Also, what thickness ply would be suitable? 6mm? 9mm?

Oh, one more thing, how much should I be paying for a sheet of 6mm marine ply?


I do have some knowledge of cad, but almost exclusivley 2d, so I may look into design at some stage in the future.

thanks,

Tom.

[alan white]

6mm would be way too thick for a light kayak. 3mm is about 1/8", doorskin thickness. There are a lot of kit kayak manufacturers, of course.
I don't know about DXF, but kayak hull plans are cheap and there's not much time or space involved in lofting the stations, after which a thin wide ply batten laid over the molds can be used to get panel shapes. If the molds are faired, there's no need to loft more than the stations.
You would have to trust your CNC to accurately cut panels that might not show discrepancies until mostly wired together! Good way to go if you're making 10 boats, though.
I don't know where stoke is, for shipping. Stoke? Where is that?


Alan

[mut]

Im in the uk, midlands.

the cnc cuts to accuracy of like .02mm or something daft, so i dont think thats an issue.

3mm really!? wow. does it need to be marine ply?
So after its been put together, its fibreglassed right? is this difficult, bearing in mind i have no experiance with it.

thanks.

tom.

[alan white]

Accurate or not, it will only cut what it's reading, and I'm just saying that, while I have no experience with CNC routers, I can imagine very accurate mistakes occur sometimes and they don't show up until the pieces are cut and one attempts to sew them together. By then, a lot of material and labor has been spent.
I suppose tests could be done with cardboard.
I would use an exterior ply at least. A thin ply kayak might be skinned with light cloth outside for abrasion and a bit of extra strength (and perhaps another tape layer at the chines, I think), along with coving the inside chines and keel/stems and taping the joints inside. This should produce a light and stiff boat, stiffer and much lighter than a poly boat, which is admittedly many times tougher. But the light weight makes the ply kayak so nice.

[mut]

Ahh i see what you mean about accuracy.
i have some 3/4mm ply coverboards here, we usually scrap them, so ill do some test cuts with those!

just need to find those plans now

cheers

tom.

[donncha]

There are good free plans for a sea kayak at:
http://www.guillemot-kayaks.com/guil...ue_kayak_plans

They do a number of kayak plans but you have to pay for the others.

Also I remember reading a build guide by an Italian but I can't find it.

Found this build guide also if you are interested.
http://homepage.eircom.net/~sizler/index.html

I haven't built it myself, but a few years back I was looking for something like you are. In the end I just left it and concentrated on bigger boats.

You would proberly be looking for something a little more suited for inland stuff though.

[Chris Ostlind]

Hi Tom,

You are going to have a really tough time finding someone who will part with their .dxf panel files so you can cut your own CNC boat parts. There may be a boat, or two, out there of the totally free variety which is not especially proprietary in form or design. It will most likely be of the recreational variety and that sounds very much like what you are needing in the way of a boat.

Part of my portfolio is the design of kayaks and canoes in a wide range of lengths and applications. I do not give out the .dxf files to my boats to anyone unless I'm entering in a business deal that entails substantive design royalties for each boat that will be cut and sold. One of my kayak designs is attached at the bootom of the post.

If you are feeling kinda spunky and wish to design your own boat for plywood construction, there's a perfectly good piece of free software on the Web called Carlson Hull Design which will produce offsets and/or .dxf files for your purposes. It will even nest the panels for you if you fiddle with it some.

Hulls produces acceptable panel output for CNC software that can accept .dxf input (pretty much all of them). You will have to nest the panels in the cutting software, anyway and translate the .dxf file to the cut path language used by the CNC machine of your choice.

The Hulls generated .dxf file can also be ported over to a CAD software platform and you can output the files as line drawings to a printer plotter at full size and then use the output as full sized, paper templates to layout on your plywood. Hulls can be downloaded here: http://www.carlsondesign.com/ the part about the Hulls Shareware is down near the bottom of the page. There are many, many boats in the included library of free designs and many of them could be easily adapted to the needs you might have in a boat.

So, there are several routes for you to use and a bit of nice, simple software with which you can create the boat of your passion.

If that sounds like too much stuff to haggle with, then most designers will sell you a good set of plans for about $75USD and you can build the specific boat you choose from their design portfolio.

Either way, it looks like you are about to embark on a fun and interesting adventure. Please keep us informed as to how you move along the path of discovery.

Chris Ostlind

[JEM]

I'd suggest "getting your fet wet" with an easy design first, cut by hand. A pirogue, simple canoe, boatshelf, etc.

Getting a .dxf file is sometimes difficult because the designer will have concern about the file getting passed around. I have a set of free kayak plans that I'd be willing to share the .dxf file for.

http://www.jemwatercraft.com/FreeKayakPlans.php

[mut]

thanks for the advice guys. i found some 3mm ply cover board that was destined for the scrap bin too so now i have something to test with.

that would be great JEM, ive just been taking a look at the pdfs, they look just the job!

thanks,


tom.

[JEM]

shoot me an e-mail if you want the files in .dxf

[mut]

done thanks

[Pericles]

Tom,

For information.

http://duckworksmagazine.com/03/r/ar...ass/bottom.htm

http://www.wessex-resins.com/

http://www.robbins.co.uk/

http://www.woodenboat-digital.com/woodenboat/20070910/

Good luck,

Pericles

[mut]

cheers, i think im gonna cut some parts tonight.

[mut]

so i cut the parts today. i rearranged the dxf that JEM sent me a little so i could squeeze more on a sheet.

anyway i cut the parts and put em together roughly, so far so good!

[JEM]

Looking good so far!

Yea you could nest the parts a lot tighter. The file I sent you have them layed out so they'd be easy to draw and cut by hand. With a CNC, you can get the parts very close together.

Mind if I use your pictures on my site? Would also love to have you post a build log in my forum if you get the chance.