Acceptable Stringer Material?

[bylawren]

Mr. Horton's book recommends rot resistant cedar, redwood or cypress for stringers. That said, I have located a local source for clear, 1" x 6" kiln dried *spruce* in 18' lengths. (I haven't gotten the price quote yet...  =8-0  )  Where the 18' lengths would eliminate the time required for scarfing, does anyone have any advice of the potential advantages/disadvantages of using spruce vs. the other recommended stringer materials?

 

Thanks.

[Action Tiger]

I have used SPF (spruce, pine, fir) fascia boards for gunwales and stringers on traditional style SOF boats. I have one frame still hanging around after 20 years of abuse, including the last 5 hanging in the weather, unskinned, as my shingle.

If your "spruce" has tight grain, say 15rpi, and is knot free, it should be fine. If you oil your frame well, and keep your boat dry and safely stored, your boat should last just fine. Dry it out after use, and keep it that way, I mean, not never get it wet!

[Hirilonde]

I have been waiting for years to see a Spruce/Pine/Fir tree.

[Action Tiger]

Their wood is a powerful UV protectant.

[WaveyDavey]

While discussing stringer material...  Has anyone utilized laminated Okoume to fabricate stringers for longer boats 19 - 20 feet?  I have made just about everything else out of the stuff and it has held up well in come pretty dicey situations?  

 

Just curious.

[Hirilonde]

While discussing stringer material...  Has anyone utilized laminated Okoume to fabricate stringers for longer boats 19 - 20 feet?  I have made just about everything else out of the stuff and it has held up well in come pretty dicey situations?  

 

Just curious.

 

By laminate Okoume do you mean plywood?  If so, then no.  Like all plywood the grain alternates in layers.  This is not optimum for items that only need strength from 1 grain direction.  If oriented according to the outer layers, all plywoods would still have almost half of the layers doing almost nothing of benefit as a stringer.  I used 18mm Okume for my Lapwing rudder because it was strong enough.  I used self-laminated Douglas Fir strips for the centerboard, because it was needed.  Jeff has speced stringers as solid RWC.  You would need to achieve the same for any material and I doubt even BS 1088 Okoume would meet Jeff's spec. and as a stringer.  I build Okoume ply boats, and use solid wood as stringers, even when glued to the ply for the entire length.

[WaveyDavey]

That is what I expected.  The only time I was able to make it work was when (yes plywood) between one of three layers of 3mm, was a strip of 12k weave carbon.  It was kind of a risk because I had to perform a pretty intense lam, in place sans vacuum bagging.  Too much time and too little understanding of material science once in a while make for near miracle break throughs.  However more often it makes for a colossal thud!

 

Thanks.  

 

Oh yeah, the reason I even consider this is that here on Oahu you have to be on the ball with your material sourcing, as the Locals say " If you see it buy it.  It may not be there tomorrow Bra!"