Picking Doug Fir 4x8x20 to resale for boat lumber

I could use some guidance on picking out 4x6 & 4x8 20' Douglas Fir to be resawn for my Wharram Tanenui build.

It's very beautiful wood. No. 1 & Better, air dried, straight grain. I can pick thru & choose my pieces. I'll need about 12, 4x8x20 or 16, if 4x6x20. Or combination of the two widths.

I saw them a few months ago when looking for a house project. Was amazed at the quality of the beams! Straight, no knots at all, really nice lumber, it looks like cabinet grade wood.

When I get the 4x6/4x8 home I'll resaw them a fat 1/6" over size & let them dry & relax for a few weeks. Then finish them to final dimentions.
Most of the sizes needed are ¾"x2" & 3", 2"x2" and a few pieces for crosbeams 5-½" wide or so.

I know I want grain that runs a long way before crossing 1" out of line.
But how straight is straight enough?

I'm guessing they will be flat sawn mostly. I didn't pay real close attention when was there last.

What are some likely ways they will be sawn & what do I want?

When I resaw them I can cut them to optimize grain direction. But don't know what that is!

If anyone has links or any help, ideally specific directions it would be most helpful and appreciated!


I have been a contractor for many years. It's just laying out & resawing for optimum strength for boat building is new. Not resawing lumber.

Cheers, Allen

 

I thought Glen-L had something about resawing but I didn't find it ... exactly.

Here's the online article I did find: http://www.glen-l.com/wood-plywood/bb-chap5.html

It does address grain orientation on page 2.

 

Doug fir standered and better means #2 and better. Then you have #1 and select structurel. When you look at SS you want electronic grading for density which all the truss builders use and buy. Density = strong. These boards will be heavier then all other grades. On boats, strong = weight. That is the trade off.

 

There are lumber grading rules for boat lumber somewhere on the internet, it will go something like this (this is for select supreme):
checks: small surface seasoning checks only. one at ea end
skip: very light skip at one edge, light skip on back
torn grain: very light, not more tan 3" long
Grain: medium (4 or more grain per in)
knots: two pin, sound, firm, encased, well spaced
pitch;slight traces
pockets; one very small
slope of grain: 12 to 1.

You will also want to study the grain carefully for any crushed grain that comes from lifting with fork lifts, mishandling, or from the metal sling straps. Cross grain damage is hard to spot unless you are looking for it, and it greatly weakens the wood properties.

 

Abosely, consider yourself extremely lucky to find decent lumber in Hawaii!
IMO, the bulk of the lumber available in the islands is trash, rarely even meets stamped grade, yet always carries a premium price tag.

I guess all regions have their marketing quirks, last time I was in Denver, I needed 4x10 beams, and they were just not available in lengths greater than 8’, that in an area that’s surrounded by forests!

 

That might explain why the forests are still there !

 

You will want to resaw them so the resulting pieces are quartersawn.
Grain is straight enough when every fiber in the wood runs from one end to the other end of the piece.