Best Wood for Chine Logs

[ancient kayaker]

I build canoes using marine ply. To eliminate the need for epoxy and glass I use chine logs to reinforce the seams. My joints fit perfectly so don't try to sell me on the gap-filling properties of epoxy.

Here's the question: the chine logs are stressed only across the grain so a wood with good cross-grain strength is indicated. Which woods would be suitable? I have been using cedar, only because I can get it knot-free but it is not very strong. I understand poplar has good cross-grain strength but some people say it rots easily.

Is cross-grain strength the same thing as split-resistance?

[alan white]

White oak (e.g.) would simply be smaller dimensioned than a lighter wood like cedar--- let's say you had a log of cedar at 1 1/2" x 3/4". The oak might be 1" 1/8" x 5/8", without calculating maybe the same weight, but far more bendy due to smaller dimensions and hence less chance of cracking and most importantly better at holding fasteners by a huge margin.
Stiffness comes from the panels, aqnd not the chine dimensions. The chines ought to be considered as the means of connecting panels and setting the boat up for building.
Resistance to splitting, fastener-holding, bendability and rot resistance---- prime qualities of chine logs.

Alan

[ancient kayaker]

I rarely use fasteners since most of my construction is glued. White oak (and ash) has often used in the past for canoes.

Since posting it occurred to me that, since I glue the chine logs to marine ply, the chine log material need not be stronger than the face veneer (Okoume/gabon). Since my canoes are ultralight single-seaters (<20 lb) density is important, which is why I have used cedar to date; it is also very easy to work.

Perhaps I should make (and break) some test pieces to see if the okoume or the cedar fails first.



Recently I experimented with twisted or "tortured" ply construction for the canoe bottoms (so far mine have had flat bottoms). I glued keelson strips to the ply garboards before bending to ensure gap-free joints, intending to plane the keelsons to fit a simple rectangular section keel after bending the panels. The objective was to avoid carving a complex Tee-shaped keel out of the solid. The idea worked well, quick, easy and perfect joints using non -gap-filling glue. However, after bending & twisting the bottom shape I found that it had about three times the rocker that I should have got by twisting a plain ply panel. It did not matter as it was only a trial. I expected the presence of the keelson along the edge of the ply panel to increase the stiffness of the panel and cause it to twist asymmetrically about its axis but it went in the opposite direction what I expected. I need a wood with low stiffness with the grain and lots of strength across it, but I that it exists. I shall have to modifiy the plank development and try again.

[sigurd]

What about hickory for chine logs then? It is fairly flexible I think, and super tough, and I think it is split resistant too. Not sure about its resistance to rot and stuff? I was thinking about using it in place of oak for a sewn 3mm kajak, since I figure the thin skin might be prone to splitting and leaking, from water expansion/drying contraction. No idea really, just thinking.

[sigurd]

look, I got this great paper from one of these fellows in here.
http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch04.pdf
It lists tensile strength across the grain, that's what you need right?

White Ash, American Beech, some oaks and a few others seem to stand out. Unfortunately hickory is not well represented in this column.

[alan white]

I'm guessing hickory isn't so good in the rot resistance department. White or live oak stands out amongst all of the open grained hardwoods, and millions of boats have been framed with it.
When you seal wood up in the bottom of a boat, particularly a boat that may not always be kept dry, why no use a wood that could withstand moisture seepage for an extended period of time?
I haven't heard of hickory being used in such applications, and without looking it up, I'd bet it's because hickory isn't any better than red oak where rot's concerned.

[sigurd]

Google is my friend: http://www.boatdesign.net/forums/wooden-boat-building-restoration/hickory-vs-oak-16618.html

Incidentally I read somewhere today that this or that very heavy species had superior mechanical properties in almost every respect to white oak, except for splitting resistance. Doesn't however automatically mean that WO has excellent splitting resistance - the link in the link I gave says it has a tendency to split when nails are driven in, unless predrilled.
Are there different kinds of splitting resistance? I guess the nail driving is not a direct analogy to the cross grain tensile tests I gave earlier since a softer wood will compress around the nail.

[alan white]

Cross grain strength may have two ways of being measured. One would be related to sudden shock and the other to simple tension.
White oak, as said, is very rot resisant. It is also easily steamed and it holds fasteners well.
It is prone to surface checking, a good reason to keep the varnish up, as it doesn't like to get wet and dry out cyclicly, but prefers either staying dry under paint or varnish or staying wet for long periods as in the bilge of a typical wood hulled boat. The checking is usually only cosmetic.
There are, I'm sure, many species that rival and even exceed the qualities of white oak for boatbuilding. However, I have never concerned myself with non-indiginous woods since I'll likely not find them for sale in my area.
As far as splitting goes, I personally think white oak is relatively tough. No hardwood (and most soft woods) should be screwed without a hole being drilled. The best tensile test would be an attempt to pull a block apart by applying an increasing load, which most closely mimics real world conditions.

[FramerDan]

I'm not highly experienced in boat building yet, but I do know hickory fairly well. I've done my fair share of fence repair, and at one point removed an old fence built with hickory posts. Although they didn't hold up quite as well as some white oak posts I've seen, they were certainly fairly rot resistant. I've also been drumming with my hickory drumsticks for quite some time, and would say that, while they still don't resist grain separation like oak sticks, they should hold up pretty darn well on a boat...unless you plan on senselessly beating cymbals with your canoe.

[alan white]

Do you know of any historical use of hickory in boats? It would be interesting to see if it had ever been a practical boat wood. Often, availability is the mother of improvisation when it comes to boat woods.
In any case, epoxy encapsulated construction in a light trailered/carried craft is an entirely different matter. There is no historical precedent for epoxy construction, and much experimentation has yet to be done with different wood species.
You'll find that experienced boatbuilders are a conservative lot. They know what works and often let other people take chances. After a few years, if an idea has been successful, then and only then do they consider implimenting a new method, material, or design idea. Mostly because experimentation costs a lot of money.

[alan white]

I build canoes using marine ply. To eliminate the need for epoxy and glass I use chine logs to reinforce the seams. My joints fit perfectly so don't try to sell me on the gap-filling properties of epoxy.

Here's the question: the chine logs are stressed only across the grain so a wood with good cross-grain strength is indicated. Which woods would be suitable? I have been using cedar, only because I can get it knot-free but it is not very strong. I understand poplar has good cross-grain strength but some people say it rots easily.

Is cross-grain strength the same thing as split-resistance?

I believe that spruce has very good cross-grain strength in a lightweight application. I find that at least for firewood, it splits harder than any other wood I burn, including red oak, maple, poplar, pine and so forth. It makes sense that spruce is the preferred spar material for sailboats. For it's weight, it must have a very high tensile strength across the grain.
Fir has a rowed, or interlocking grain that makes it hard to plane. I'm curious whether that same quality would also give good cross grain strength.
In any case, chines seldom would be stressed enough for that kind of strength to be a big issue. I think I'd be more concerned with fastener-holding. What kind of fastener do you use?

[FramerDan]

You'll find that experienced boatbuilders are a conservative lot. They know what works and often let other people take chances. After a few years, if an idea has been successful, then and only then do they consider implimenting a new method, material, or design idea. Mostly because experimentation costs a lot of money.

With that in mind I'll keep you posted as I build my first few boats :)

maybe I can learn good techniques from you guys, and you can learn from my...innovations ;)

I guess I've got to figure that I might as well make mistakes while I'm practicing, rather than try something new and dangerous 10 years down the road when I want to live on the darn thing.

With any luck maybe I'll stumble on something worth while.

I did find more info on hickory though... doesn't glue well, so won't work for this application. Low rot resist, so further, bad. Oh, and it splits when nailed, and dulls all your tools. Duly noted.

[ancient kayaker]

Somehow I got unsubscribed from this thread so I didn't get e-mailed about this year's crop of posts. I wasn't intentionally ignoring you!

Sigurd: that paper of wood properties is a mine of information, I shall be digging deep into that, thanks.

Alan: others have suggested spruce, I will have to check it out. Some species of fir are used a lot in boats, masts also; but spruce is a lot easier for me to get. I don't use fasteners at all, just glue. Generally I avoid epoxy since I can get well fitted joints using my construction methods.; Titebond IIII is nicer to use.

In general, rot-resistance is less of a problem to me than for some since my boats get taken out of the water after each trip and are dried out; also paint scratches are touched-up scrupulously.

FramerDan: sounds like hickory is the perfect wood for a temporary boat!

[sigurd]

where did you see hickory is difficult to glue? What glue?

[alan white]

Somehow I got unsubscribed from this thread so I didn't get e-mailed about this year's crop of posts. I wasn't intentionally ignoring you!

Sigurd: that paper of wood properties is a mine of information, I shall be digging deep into that, thanks.

Alan: others have suggested spruce, I will have to check it out. Some species of fir are used a lot in boats, masts also; but spruce is a lot easier for me to get. I don't use fasteners at all, just glue. Generally I avoid epoxy since I can get well fitted joints using my construction methods.; Titebond IIII is nicer to use.

In general, rot-resistance is less of a problem to me than for some since my boats get taken out of the water after each trip and are dried out; also paint scratches are touched-up scrupulously.

FramerDan: sounds like hickory is the perfect wood for a temporary boat!

I recall that Howard Hughes Spruce Goose held together pretty well. And masts are almost always spruce---- sometimes pine or fir, but mostly spruce.
The ideal qualities of a mast, or any spar, are firstly strength to weight, where failure involves fracturing due to over-bending.
I think it's fortuitous that the same common variety of spruce found for cheap at any lumber yard also happens to be adaptable to boat framing members (especially when well sealed).
Would air-dried clear spruce (eastern, adirondack, sitka, etc.) be superior to the lumber grade kiln-dried variety?
Absolutely. Kiln drying causes spruce to seperate internally, evident when inspecting a 2 x as short checks and fissures on the surface. Some pieces don't have those checks, or have very few.
Many varieties of spruce lumber have small knots throughout, no matter how carefully you go through the pile. Then you should just go elsewhere and try again.
Fir from Depot and Lowes is good if you go through the pile, sometimes really good. Fir's heavier at about 34 lbs cu ft. (spruce must be about 27-28 lbs).
Not a big enough difference if it's only chine logs.
Fastener-holding ability of any soft wood isn't good. I like to pre-drill and drop some Gorilla glue into the hole just prior to fastening to strengthen and harden the screw hole, which to my thinking solves the poor fastening problem.

Alan

[ancient kayaker]

Spruce is a great structural material, and it takes nails very well as anyone who has framed a house or repaired a fence would know. My local lumberyard will let me rummage for the good stuff as they are familiar with my deviant behaviour of building canoes, and there is another yard only an hour away that I've heard good thing about and has lots of air-dried stock. I will visit it come Spring. In the meantime I will make and break some test samples with spruce, poplar, and maybe oak and fir too, as I like the security of test data over book data.

I very rarely use fasteners so holding problems don't exist for me so long as the wood takes glue.

Thanks for the advise!

[peter radclyffe]

Do you know of any historical use of hickory in boats? It would be interesting to see if it had ever been a practical boat wood. Often, availability is the mother of improvisation when it comes to boat woods.
In any case, epoxy encapsulated construction in a light trailered/carried craft is an entirely different matter. There is no historical precedent for epoxy construction, and much experimentation has yet to be done with different wood species.
You'll find that experienced boatbuilders are a conservative lot. They know what works and often let other people take chances. After a few years, if an idea has been successful, then and only then do they consider implimenting a new method, material, or design idea. Mostly because experimentation costs a lot of money.

although not structural i've heard it's good for fairing battens, which says a lot about it's uniformity over the years

[peter radclyffe]

I build canoes using marine ply. To eliminate the need for epoxy and glass I use chine logs to reinforce the seams. My joints fit perfectly so don't try to sell me on the gap-filling properties of epoxy.

Here's the question: the chine logs are stressed only across the grain so a wood with good cross-grain strength is indicated. Which woods would be suitable? I have been using cedar, only because I can get it knot-free but it is not very strong. I understand poplar has good cross-grain strength but some people say it rots easily.

Is cross-grain strength the same thing as split-resistance?

spruce & ash if you seal them, but sealed or not teak is the best, the weight is not a problem,

[Rosamond]

Thanks for all the collective knowledge you guys had in this old post regarding Hickory etc.
I am also thinking of using hickory, for the gunwales of a traditional aleutian skin on frame sea kayak. What made me think of using that wood is simply this: or several hundred years, Hickory was the wood of choice for Nordic skis. A similar situation to a kayak, where springiness is highly desireable, and the wood is put in a wet environment for a day, then dried out again, over and over for years.
I suspect I'll maybe have to treat this hickory with something and also coat it in epoxy...the bases of hickory skis were traditionally impregnated with pine tar....
But the memory of the springiness of hickory in my old cross country skis gives me hope that such an experiment might turn out well. If not, I can always replace them. Wish me luck. I'll let you know.

[shorejob]

Hi guy's, new member here...I felt that I should chine in on this subject lol. The traditional wood used for chines, come's from the ELM tree.

[ancient kayaker]

Elm has great resistance to rot when permanently wet. It was formerly used for pier pilings below low water level and for buried water pipes.

It's also fine when kept dry, but it rots when exposed to both air and water. It has a complicated interlocking grain and the built-in stresses are likely to cause cracking and twisting in small pieces but it is ok in very large logs.

I can't see it is a good candidate for chine logs especially in a boat that is dried out, but it maybe OK under the waterline if you are re-creating a large sailing ship with heavy timbers and continuously wet bilges. That is probably the traditional use you were referring to.

[PAR]

You beat me to it Terry . . .