View Full Version : Cutts method of double planking?

01-09-2001, 09:29 AM
Is anyone familiar with the Eddie Cutts method of planking? Quickly, it's a double planked hull with a Kevlar cord set in groves between the layers. No metal fasteners, smooth hull and frameless. He use to operate the Ralph Wiley yard in Oxford, MD, on the eastern shore of the Chesapeake. Does he have a site? Do you need a license for the method? Etc. . . .

Ian McColgin
01-09-2001, 10:56 AM
The WB article was clear enough that you could probably do it yourself. Were I building a boat, his method would be my first choise and I would try to get him to set the scantlings. Cutts deservs at least that. But if he refuses to license, I donno . . .

Keep us informed. It's a method that needs wider exposure.

Dayton Eckerson
01-09-2001, 04:36 PM
I've been over to his yard several times -- its one of my "must-see" spots whenever I'm on the Eastern Shore. They have built some great boats using that method; my only concern is with ease of repairing. I don't understand how you replace a damaged plank without affecting the integrity of surrounding planks. Perhaps they have figured out a good way to do it. I would just pick up the phone and call the yard. They are very friendly and informal over there. The number is 410-226-5416. I can't remember if they have a web site. Do a search on "Cutts & Case". Good Luck.

Ian McColgin
01-09-2001, 04:40 PM
I bet it's just like any other monocoque repair - dutchman with care.

John Gearing
01-10-2001, 11:47 AM
I seem to recall from the ads they ran in WB that it was a patented process. Whether that means they would charge an amateur for a license of not, I don't know. Don't know what you do if you have damage that severs the kevlar cord that seems to be the key to tying the hull together.....

01-13-2001, 02:39 AM
To me, the Cutts concept never made sense structurally.
To explain, think of strip canoe construction, with a light material (cedar) on the inside and a stiff but heavy material (glass/epoxy) on the outside of a sandwich. The glass is located where it can provide stiffness to the panel. Like the flanges of an I beam.

The Cutts method puts the strong material in the middle of the panel, where it can't add stiffness. Ever see a beam with the flanges in the middle?

Ian McColgin
01-13-2001, 08:29 AM
But that's not exactly the function of frames (or ribs if you're from someplace else) in wooden boats. Rather, they keep the planks in place and provide a route for some of the stress distribution. The contact between planks provides stress distribution in the other direction.

The Cutts method allows that stress transfer in both ways which would be difficult to achieve with just glued wood in one grain orientation. Traditional cold molding accomplishes this by some layers in a different orientation, but they still do not act as beams.

As the size increases, structural bulkheads become increasingly important in both cold molding and cutts. But for each method, astoundingly light purely monocoque structures are possible.

In metal construction and some forms of plywood construction the frames do act as a beam and prevent (or, if spaced too far apart, accentuate) oil canning.

01-13-2001, 09:50 AM
I missed the issue it was featured in WB. Seems a few letters where written about it as well. Issue 78 was when I was skippering in the islands and missing WB back then was common. I was interested in the method for stress dispersal. Seems like the bronze strapping idea taken to greater lengths. I can see how it could replace framing in small craft, but larger . . .

I'm interested in some additional reinforcement in the ends of the boat I'm building as there is quite a bit of bow overhang and spreading the chain plate loads over a larger part of the hull. As designed she'll do, but I've played with the strapping idea in more conventional forms and thought this method a good idea, with the weight savings a plus. My real interest is in someone's use of this technique. Problems, thoughts and advice in use. Talking with inventors of systems is like calling the "references" listed on a resume. You know the response you'll get before you make the calls.

G. Schollmeier
01-13-2001, 10:25 AM
Beams with the flange in the middle are very strong. Just harder to build with. A sandwich with wood on the outside and glass in the middle is also very strong. The Cutts method works as Ian said. Gary

[This message has been edited by G. Schollmeier (edited 01-13-2001).]

Tom Lathrop
01-13-2001, 11:34 AM
I've followed this construction since Cutts published it and do not see the problem that he is trying to solve that can not be done in another way that makes for fewer problems in both construction and maintenance. I've no doubt that it works but---the planking must be thick enough to accept the transverse groove which has to weaken it some, there are now two layers of planking to spile and edge glue instead of one and the hull still may need external sheathing for protection. I think that equivalent hulls will be costlier and probably heavier when built by the Cutts method than some of the other ways of getting the same results.

Still love to visit Cutts yard when I'm in Oxford though. His boats with their distinctive round cockpits and horizontal truck-style steering wheels are also way out of the norm. Very interesting, but they did not catch on either. Doesn't mean that his ideas aren't good, just means they did not appeal to the mainstream.

G. Schollmeier
01-13-2001, 02:03 PM
Yes Tom, I think this is just the long road to the same result. Sometimes the paths we choose are for reasons not obvious to others.

Ian McColgin
01-15-2001, 08:27 AM
Gary's right that the method has to do with solving a particular problem. Cutts found a way to make a cold molded hull that uses and wastes less epoxy, uses dimensional wood in sizes large enough that kerf loss is not a painful waste, and has a much reduced problem with voids.

[This message has been edited by Ian McColgin (edited 01-15-2001).]