Monday, January 9, 2012

Rib Squish for Simmler

Maybe you noticed there's a mini Simmons design on the surfcorr album (Simmler), but no kit available. No? Didn't notice? Didn't even know about surfcorr? Go check it out, then (and read the liner notes). Simmler is the current R&D subject. Cutting now.

An hour into cutting, noticed the notches were coming out in two different sizes. Usually they are all the same. Checked the collection of parts cut so far and they all had the same problem. What now?

Ahh, but that's not a problem - that's rib squish. Prepared these files months ago, and forgot that Simmler has a core pattern variation that requires different notch sizes.

Rib squish: Compare the quarter isogrid pattern above to most of the other board core top views, and you'll see that the diagonal pieces have less slope to them. The pattern is kind of squished in the direction of the stringers. Normally, all parts intersect at the same angle. But with rib squish, you get two different intersection angles, so some notches have to grow and others shrink.

Why rib squish for Simmler? I forget why. Think it was just time to try it. It looks like I also spaced out the stringers wider on Simmler, so it has two fewer stringers than other short boards. Squishing the ribs keeps the hexagons from getting too big in this case, and makes up for some of the lengthwise strength lost by having fewer stringers.

If you look at the art for Glass Fish on surfcorr, you'll notice the center board core has negative rib squish - or rib stretch. The point there was to get the core pattern to fit better in the tail section.


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