optimal wood strip dimensions

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jimlgordon
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optimal wood strip dimensions

Post by jimlgordon » Mon Nov 20, 2017 10:24 pm

I am preparing to build a Chaa Creek Expedition. The plans call for 1/4 inch thick strips. I came across quite a bit of material already cut to 3/16 and was wondering if 3/16 inch would be ok for 3/4 inch wide strips.

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Cruiser
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Re: optimal wood strip dimensions

Post by Cruiser » Tue Nov 21, 2017 9:38 am

Hi Jim,

As I understand the idea of "strength" in a composite hull, the 1/4" spacing will give a stronger final product than 3/16" ... now whether that matters to you or not is a whole other question.

Using heavier or more glass, say 9 oz. glass (or multiple layers) compared to 6 oz (common) will increase strength, using hardwood strips over cedar will also increase hull strength ... the hull will be stronger, but horribly heavy. The idea is to balance what you intend for the boat with the material selection .. paddling a lake with the family requires one set of needs, tripping with portages and gear loads is quite another.

Builders have to make those choices when they pick materials and decide what their build will look like. If you consider that 1/4" strips, in conjunction with 6 oz glass is the norm ... then using 3/16" strips may be light for that layup and an almost 20' boat. Sanding strips that thin will require careful attention to the sanding portion of the build, you won't have any leeway for over sanding ... there just isn't much wood there. If possible, make up a 1/4" batten and visually compare it to the 3/16" version ... that 1/16" makes a big difference.

If the material for the strips is a really good deal, then my opinion would be to add a layer of 4 oz (in addition to the 6 oz) to the football area (inside and out) and call it a day.

A point to consider is that the strips are not really the most expensive part of the build (especially if you make them yourself) ... take a good look at what you are saving for the "good deal" (and the additional reinforcement materials) versus just getting the correct material in the first place. The glass/epoxy is the most expensive component in the build and you may find the difference isn't as big as you think.

Just my $.02

Brian

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jimlgordon
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Re: optimal wood strip dimensions

Post by jimlgordon » Tue Nov 21, 2017 10:37 am

Thanks for the tips. I recently built a kayak with 3/16 strips and I was impressed with the strength of the hull but it is a 16 foot hull. The Chaa Creek is over 19 feet so I was a bit concerned about going 3/16... especially about sanding 3/4 inch wide strips. The 3/16 material I have in my collection was free. I may save that for a small c1 or something like that later. This Chaa Creek is intended to carry grandkids, a dog, crab traps, fishing gear, and other payloads and rough use.

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Cruiser
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Re: optimal wood strip dimensions

Post by Cruiser » Tue Nov 21, 2017 11:34 am

For heavy use, you may want to consider an extra layer of 4 oz glass on the exterior football, not too much extra weight, but more protection/strength in the most critical area.

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Patricks Dad
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Re: optimal wood strip dimensions

Post by Patricks Dad » Tue Nov 21, 2017 4:27 pm

3/16" strips should work fine. Extra care in your sanding. If you add an extra layer of glass, consider one on the inside. The biggest stress on the structure from an impact on the outside is focused on the inside. Of course an extra layer on the outside will provide better protection from abrasions (but that threat is largely independent of the thickness of your wood).
Randy Pfeifer
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Randy.Pfeifer1@gmail.com

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jimlgordon
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Location: Bainbridge Island, Washington

Re: optimal wood strip dimensions

Post by jimlgordon » Sun Nov 26, 2017 11:35 pm

I decided to go with 1/4 x 3/4 inch strips.

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