CNC/Plywood Trimaran?

[jmolan]

After seeing Russell Brown's 18' runabout:

http://www.ptwatercraft.com/

I was exposed for the first time really to the CNC Plywood boat building methods. Jim Brown of Searunner fame was there, and told me he could build this boat (he is legally blind) seeing as how there are tabs and the way the wood jigs together. It all fits so well.
So the idea has been swimming in my head.....why not be able to build a Long lean Trimaran the same way? I have spent some hours searching the web for various designers and kit builders of CNC Plywood boats. SO far no Big Trimarans. Dudly Dix has a 21' that I think is kit. And this boat really caught my eye from Lavranos.

http://www.lavranosyachtdesign.co.nz/sc_10m-multi.htm

So here are my initial questions: Can you convert an existing design into a CNC design? A boat that is already designed like?

http://www.bajayachts.com/seaclipper...es/images1.htm

The 41' Sea Clipper is a John Marples design. But if it is in paper only, is it more trouble to covert it to CNC or better just to start over?

Does anyone know of anyone doing a Trimaran in CNC? I see a few Cats but that is about all.

Can someone convert say a foam glass design into CNC Ply? Or again is this too labor intensive and better to start from scratch?

Thanks ahead for reading my questions.

[gonzo]

There is no such thing as a CNC design. You convert any design into code the CNC can use and it will make it for you.

[Chris Ostlind]

Jack,

I've done a couple of trimarans (18 footers) that were specifically designed to take advantage of the potential of having the principal parts cut with a CNC. None of them had the tabs of which you speak.

With a comprehensive .dxf file of all the parts, and the completed design in 3D, one could easily convert the bulkheads to be tabbed for location during assembly.

Converting paper plans to a set of drawings for the computer is a bit of work and it would probably be easier to just create a fresh boat from scratch, using the existing design as a jumping-off point, provided that you really like the original.

[jmolan]

Thank you both. I am starting to get a handle on it. In some ways it reminds me of remodeling a house....how many times have you heard "I should have started from scratch"
"The only thing standing between any paper design and a CNC file is time & Money"

As mentioned by Gonzo, you can get CNC files out of every design drawing. Most yards or CNC cutters prefer to convert the drawings themselves, even if the designer / NA is able and willing to do it.
So, take care, when you do it yourself you might probably end up with a effort for nothing!

Regards
Richard

[gonzo]

There was someone in the forum advertizing his services for that.

[jmolan]

I am going to contact the company that is doing the cutting for the runabout already. See what they have to say about converting plans from paper to digital CNC usable files.

[gonzo]

As I understand it, you can scan the blueprints and digitize them.

[guzzis3]

Contact Ray Kendrick. Several of his designes are built in ply and I believe he can supply the required dxf's for you at a small extra charge.

www.teamscarab.com.au

CNC isn't standardised so it depends on the system and tool they are using, that's why the cnc provider usually wants to do the setup themselves. I know boatcraft pacific does this sort of thing in Queensland, there are no doubt providers nearer you.

To be honest panelling up the hull isn't the hard part. Chined ply requires signifigant fairing, and even with a clip together ply kit you have to avoid wavy panels, make and seal the beam to float joints and teh internal bouyancy chambers etc etc.

This is why I have long argued that strip plank is a fine method. The age old argument that applying the strips is time consuming is a nonesense in the context of the total time required to build the boat. Conversely "fast build" methods address an issue which is amongst the least important.

Anyway....</soapbox>

[jmolan]

Yes thanks for the input. I talked with the company that does CNC work on Brown's skiff www.ptwatercratft.com . He usually has to "place" the pieces so they fit well on a sheet. He also came up with the "jigsaw" joint to replace the scarf. Get a good look at them on the website. Think how nice things will line up with that joint, as opposed to a scarf...... I am learning a lot here. And find the whole idea intriguing.