Vertical Grain or Quarter Sawn Douglas fir in specific components

At first I thought that Douglas fir clear, vertical grain would be preferred over quarter sawn DF in these structure/components, but since I don't know/understand how these components going to be loaded and how loads will be distributed into rest of structure.

The structures/components are keels laminated of 5 layers of 1" thick DF starting at 11", 10", 10", 9" & 8" before rounding. I plan on putting about 3" of hardwood so can round off the bottom of keels and give little extra protection on keel bottom.

The second components are stem & stern. They are 5 layers of 1" thick DF laminated, the layers are
11-½”, 10", 9" & 7-½” widths before rounding. Will be adding 3" or so the them to bring stem to finer entry and the stern to fair into rudders nicer. The bow has a fairly steep rake, didn't know if that would have bearing on choosing VG or QS.

The third components are the stringers, 1" x 3" with center to center spacing, from keel up of 14", 12", 11", 11" 8", 8" & 12" to double sheer stringers, and 1"x 3" packing pieces between stringers on the 6 bulkheads.

Would VG or quarter sawn DF with the quarter sawn layers alternating grain angle be better for these?
Lumber will be around 15 to 18 rings per inch.

Sorry if I gave to much detail about this, didn't know how much info would be useful to determine which would be best. For the Ulua Nui I'm using quarter sawn DF strips, finished planing the last 16 or so planks to ¾” today that I re-sawed from 4x10s, tomorrow will rip to width & plane them.

Tried to post pics, don't know if was successful or not.

 

You're overthinking it. It won't make a difference.

 

What is vertical grain?

 

It is when the rings are about perpendicular to the face of the lumber.

 

The grains are to run opposite the load, generally.

VG lumber is more stable and less likely to move after cutting. This is helpful in boat building because twisted up lumber is harder to laminate or lay, etc.

And you are mixing terms. Quarter sawing creates vertical grain lumber. The term comes from quartering a log into four sections and turning the cant each cut to minimize the grain length in each board, or to maximize the total amount of grains per board.

The terms I use are flatsawn or flat grained, riftsawn or angled grains, and quartersawn or vertical grained.

A wooden boat shipwright would be better suited to answer which board belongs where, but I can give it a rough go.

If you are strip planking; the wood has the highest tensile strength with the grains pointed abeam. If the board is turned; it essentially becomes flatsawn against any pressures. Of course, this changes as you plank. A board on the bottom is best the other way. But the easy way to do it is to see more grains! If you don't see grains; the board is in a flatsawn direction.

And, despite, the overly easy answer, for a sheath strip boat, Gonzo is not far off. The grain directions placed randomly in a sheathed boat also end up working in concert and providing good strength. But, he is passing on the hard work of answering well. Sorry, my Wisconsin friend. However, do not despair if you cut wrong already; follow his lead.

Now the load in a stringer is up and the grains opposing suggest flatsawn lumber would provide the greatest grain length. This is valid, but finding stable flatsawn lumber is harder, so even riftsawn or vg lumber is okay for stringers verus some flatsawn board that is twisted or could become twisted after placement.

For beauty, flatsawn lumber is where it is...and so even a sawyer intent on cutting mostly vg lumber will usually make a few flatsawn cuts to start...

 

Here is a good picture from the web. Their terms are a bit different from mine, but help explain where each piece comes from and how. You can see plainsawn or livesawn end up producing flat grains and quarter sawing produces vertical grains.

 

Quarter and rift sawing produces vertical grain lumber. For laminated components you don't need to pay for VG, plain sawn flipped every layer is sufficient. If the stringers are not laminated then the important part is that they are clear and with little grain outrun.

 

Will be re-sawing clear rough sawn DF 8x8 beams.
So can cut them to get grain orientation as wanted or at least close.

For most of components will use however grain comes out after re-sawing.
But would like to cut the wood for keels, stringers, stem & stern with optional grain orientation.

Will be 1” thick from 2” to 6” wide pieces.

The question isn’t for strip planking, probably shouldn’t have mentioned the Ulua Nui strip plank currently building because may have caused confusion.

This grain orientation question is for Wharram Narai MK IV.

Since re-sawing 8x8 lumber, would like to optimize strength where can.

Probably not a huge difference one way or another, but would like to cut wood so grain direction is strongest for given components.

Thinking keel and stem & stern strength would be impact compression as something hitting front of bow stem and hitting keel from bottom.

Hopefully this makes sense.

 

Well, this question is pretty deep now.

I will only generalize for you.

The keel would be best in something that will not twist. The grain direction opposes the load best, so a keel is best suited when laid on its width as vertically grained.

The stem would best also be something that will, or rather must not twist. And assuming laid on its width (a big assumption) also vg. Most modern stems are laminated however, and this really makes the worry about grain direction mute. If you are cutting the board and want curvature; something altogether different. A few good books have articles on selecting lumber for stems.

And there is no confusion.

If you want to attempt taking stringers from flat grained lumber; you could try, but you must be careful to bind the cut boards with shrink wrap to keep them from moving.

I'll see if I can find the text that goes into details..

 

If you want the stiffest possible piece you orient the grain top to bottom, this means when you are looking at the keel from the front you see this |||||. Same thing for the stringers and stem/sternpost. If you have material thick enough there is no need to laminate the keel or other pieces, just scarf them to lenght (1:12 scarfs).
The knees are best laminated, from flat sawn with flipped grain.
Over the centerline you can laminate a flat sawn hardwood cap.
If you plan for a two piece keel instead of cutting rabbets, make the inner part DF and the outer hardwood.

 

I thought Chapelle went into details, but not so many. The grain directions are not discussed, but drawn properly, ftmp.

If you have a box heart section; the heart is usually used as a keel, but generally not for a typical strip boat. The pith, should you have it; should be cut into strips and culled out.

Rumars post above is very good as well.

If you want to have any wood that is finished bright; that would be nicest flatsawn.

 

Thank you. I am familiar with the quarter sawn, rif sawn, flat sawn terms.

As far as strengths and superior orientations go, for the parts mentioned above, I believe DF would be strong enough in any orientation. It is stability and movement from shrinking and swelling that should be the real concern. Tangential movement due to shrinking and swelling, movement across the width of a flat sawn board for instance, is typically twice that of movement radially, or the movement due to shrinking or swelling across the width of a quarter sawn board.

I wouldn't put a quarter sawn board mixed into a flat sawn laminate because the two boards would want to work against each other at the glue joint.

My suggestion would be to use stacked quarter sawn to minimize the keel's shrinking and swelling against the garboards, or glue flat sawn board in opposing orientation, on edge to, again, achieve the radial orientation between your garboards.

 

I believe my first assumption to use vertical grain (grain going vertical looking at end of 1” thickness was correct.

The keels & stems are laminated from 5 layers of 1” thick planks and everything is encapsulated in epoxy and exterior is sheathed in couple layers of glass cloth/epoxy for durability.

The 1x3 stringers will have several coats of epoxy and then epoxy varnish in inside hull, outer side is covered by plywood, which will have same multiple coats of epoxy to seal it and epoxy varnish.



I thought I would check and see

 

Guys this is an ancient Wharram ply-on-frame design. By the time he slaps some epoxy and fiberglass in and over the joints any thoughts of movement and fastener holding influencing grain orientation is moot.

Why would you laminate with 1" boards if you have 8x8" material available? Just use the material at full size and laminate additional material where needed. Just because Wharram designed the thing to make it from hardware store materials doesn't mean you have to follow him.

 

Lamination from 1" materials into a 5" thick board from 8x8 is silly

run the board 5x5 with grains up and down, remove knots and fill all with thickened epoxy over clear epoxy

if you take a picture of the end of the board; we can tell you best way to cut it...

edited