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Grain Orientation v. Strength
By:Pete Roszyk
Date: 9/29/2000, 2:33 pm

One of the things that struck me about Sam McFadden’s test results of Nick Schades’s Strip-Built panels (this board, 23 August) arose from the large difference in strength between samples stressed with the wood grain as compared with those stressed across the grain. While confirming what I intuitively ‘knew’ as a woodworker of sorts, the results highlighted the contribution of the wood itself to the strength of the final composite.

The question that popped up, then, was: How much does the grain orientation within the individual strips have to do with that? For my Strip-Built projects I’ve been cutting my strips so that the grain is vertical, as most builders do. In their fine books, both Nick Schade ( The Strip-Built Sea Kayak at p. 36) and Ted Moores (KayakCraft at p. 49) seem to prefer this orientation as well, but seem to determine this preference by workability considerations rather than final composite panel strength. (To Nick Schade and Ted Moores: Please correct me if I've misunderstood or misrepresented your text.)

Any ideas or thoughts, then, whether we could build stronger boats by using flat-sawn strips rather than vertical-grain strips?

Beyond that, could we improve strength by additionally building the hull with the wood grain oriented vertically from keel to sheer rather than the traditional horizontal, bow to stern orientation? If so, this may have some application to my experimental hybrid ‘Strip & Stitch’ boat projects, as one could more easily make full boat-length panels cut out of rectangular sheets made of strips oriented across the short dimension of, say, a 4’ x 18’ panel.

It’d probably look a little goofy, maybe, but I’d give it a try on my next hybrid if it makes structural sense to some of you marine engineers out there.

Pete in Snohomish, Washington

Messages In This Thread

Grain Orientation v. Strength
Pete Roszyk -- 9/29/2000, 2:33 pm
Re: Grain Orientation v. Strength
Sam McFadden -- 10/6/2000, 7:36 pm
Re: Grain Orientation v. Strength
michelle -- 9/29/2000, 10:07 pm
Re: Grain Orientation v. Strength
Hank -- 9/29/2000, 8:35 pm
Re: Grain Orientation v. Strength
Pete Roszyk -- 9/30/2000, 1:32 am
Re: Grain Orientation v. Strength
Sam McFadden -- 10/6/2000, 7:45 pm
Re: Grain Orientation v. Strength
Hank -- 9/30/2000, 11:24 am
Shape factor
Sam McFadden -- 10/6/2000, 7:55 pm
Re: Grain Orientation v. Strength
David Hanson -- 9/29/2000, 5:11 pm