Any opinions on strip building with redwood?

[TomMcKinney]

Today I inspected an old shed at my sister's place that appear to have been sidede/sheathed with redwood 1x12's on the diaganol. She wants the thing moved and rebuilt-I may be able to reclaim the siding.

I would like to plane it down and rip some strips to make a nice skiff. Anythoughts on using this type of wood for a hull instead of the traditional cedar. Will be bead and cove strips, epoxied and covered with fiberglass set in epoxy

An additional issue might be that after planing the boards will be thinner than usual (1/2 inch after bead and cove?). Will short hieght in strips create any problems other than more strips?

Thanks

[pcford]

It is said that redwood is too brittle for boat work.

[Bob Smalser]

http://forums.wcha.org/showthread.php?t=236

http://boatdesign.net/forum/showthread.php?t=138

Redwood is certainly usable, and many strippers are built from it, including by members of this forum.

But it isn't very strong for its weight. It's about as as heavy as the hard cedars like Port Orford, which are around a third heavier than the soft cedars like Western Red, yet Redwood has around the same impact resistance as Western Red. So building to the same level of strength, you will wind up with a much heavier boat.

Other than that, the USDA tests don't mesh with Redwood's reputation as an exceptionally stiff, brittle and/or easily-split wood.
But laboratories and practice differ. Stiff compared to what? Port Orford, a wood of the same weight? No. Northern White, a wood of the same strength but a third less weight? Yes.

[Todd Bradshaw]

Core strength in a stripper isn't particularly critical (you could build one with foam if you really wanted to and can always adjust the glass schedule if needed). For normal use canoes and kayaks, the strength, durability and weight are well within the desired range and not far from those of cedar, spruce,etc. The color isn't too bad, either. Not as rosy as some cedar, but not really as boring as some would think it might be. It's usually a bit softer and easier to work than other woods when you're fitting and hand tapering strips with a plane and it can be a bit more brittle when you're stripping areas with a lot of strip-twist along their lengths. Once in a while one shatters on you as you twist it into shape, but usually it happens as you do it, not six hours later when you're sleeping and the glue has dried. I've never used bead and cove strips or really felt that I needed to, so I can't say how well it goes through the router. These boats are redwood.

http://webpages.charter.net/tbradshaw/Sails/biggie%20003%20copy.jpg

http://webpages.charter.net/tbradshaw/Sails/Drift%20A.jpg

http://webpages.charter.net/tbradshaw/Sails/Drift%20B.jpg

[Todd Bradshaw]

Up close. You can certainly use narrower strips. You'll just need more of them.

http://www.imagestation.com/picture/sraid220/p102ad637dca053aee028e931e83649dd/ebac87d1.jpg

[openboater]

my first stripper was redwood, sheathed in glass / epoxy.

17' c-1 racing canoe. worked just fine.

use a circular saw to cut strips, easier than a tablesaw. just make a good big guide.

[George Roberts]

Wood with glass faces is different than glass with wood core. Use the right scantlings.

I like redwood for a stripper. I even like burl for a stripper.

[Bob Smalser]

Core strength in a stripper isn't particularly critical (you could build one with foam if you really wanted to and can always adjust the glass schedule if needed).

Lovely work, Todd, but It'll take a lot of glass and goo to make up the difference between 15 and 28 feet. I always understood it was only in GRP where core strength is immaterial.

The weakest Redwood breaks when a 50lb hammer is dropped on it from a height of 15 feet. That height for the woods closest in weight to Redwood is around 28 feet. Western Red Cedar at around 25% less weight is 17 feet.

Know of any engineering data on this type of panel arrayed by core species/thickness and layer of fabric? Glass and epoxy aren't weightless. Seems to me you're either gonna have a heavier boat, or a weaker boat, and a builder will have to choose between the two when deciding on scantlings for Redwood.

[Todd Bradshaw]

There you have it! If you're planning on dropping hammers on your boat from high altitudes, don't use redwood! On the other hand, the big canoe in the top photo is one I built 30 years ago and it's still doing just fine. I do try not to abuse and/or break my boats, but in real-life usage, I've never found redwood strippers to be significantly heavier or less durable than cedar ones or to require any difference in the weight and type of fiberglass layup used to sandwich the core. The boats I used to build from sitka spruce (my favorite stripper wood) were a bit harder to gouge or dent because the wood was harder, but back then I could get 20' spruce 1x12's for about $25 and this is no longer the case. Chances are pretty good that if you hit a rock hard enough or one that's sharp enough to seriously damage the boat, it really doesn't matter which core wood you used. You're going to be doing pretty much the same repair whether it's redwood, cedar, spruce, mahogany, etc. If I was building a real wooden canoe or small boat - like a little lapstrake with no glass, or planking a wood/canvas hull I don't think I'd even consider redwood because of it's brittleness. All that work just isn't worth the risk, but as a core where fiberglass is doing most of the real work, I haven't had a problem. I haven't destruction tested a bunch of samples, but real-world use over a number of years seems to be the most accurate test available and they pass without a problem.

"I always understood it was only in GRP where core strength is immaterial."
.....to be perfectly honest, strippers probably have more in common with a foam-core composite GRP We-No-Nah than they do with a wood/canvas Old Town or Chestnut. Even calling the fiberglass layers "sheathing" is pretty misleading as they are really the key structural components, rather than just something to prevent abrasion. George has as good of a handle on specific scantlings for strip/fiberglass constructions as anybody on the planet, but you'll likely to have to torture him to get him to give up the info.

[George Roberts]

Todd Bradshaw ---

To be fair I have given shared my scantlings in the past - 1/3 glass cloth, 1/3 resin, 1/3 wood by weight is about optimal strength:weight. More layers of light cloth rather than fewer layers of heavy cloth.

As those ratios change the composite properties change. 100% wood is a lot different than 50% glass, 50% resin.

And I have been very clear about my view of 6oz glass over 1/4" wood strips.

I don't know what more I can share.

[Bob Smalser]

There you have it! If you're planning on dropping hammers on your boat from high altitudes, don't use redwood!...

;) I agree that if you hit a rock hard enough, the difference between quarter-inch and 3/8" planking is moot, regardless of the type of construction.

But as Redwood only has around half the impact resistance of woods of similar weights, if you build a Redwood boat the same weight as in cedar, you'll have a weaker boat regardless of whether you use one layer of fabric or three. I also agree that's not as important as the raw strength figures indicate, but I'd still want to know that up front when selecting wood.

[djswan]

I have found reclaimed redwood from some interesting places. I have used it for beams, trim, furniture and floors. The floors we harden by beating and burnishing many coats of finish on it. I don't know if the same techniques can be used for a boat. Derek

[Todd Bradshaw]

George, I know you have, I'm just giving you a hard time. If I had layup questions for strippers, you're the man I'd most like to consult with to find the answer.

Bob, I hear what you're saying, but just haven't seen any evidence of it in real life experience with boats that are decades old. I think you're assuming that the core material in a stripper plays a much bigger role in the boat's strength than it really does. In some ways, even calling them a wooden boat is kind of a joke. Back in the early days of WoodenBoat, every time they mentioned strip canoes or heaven forbid, ran an article about them, the traditional boat folks would freak and start writing letters to the editor about these phony woodies. Thankfully, things have changed, but realistically you have to look at a stripper as a cored composite boat where the core's job as simply a spacer, holding the load-bearing skins apart may often be it's major, non-cosmetic function. That's why you can even build a decent stripper from balsa wood if you can afford it. I wouldn't recommend it for whitewater due to it's lack of resistance to crushing (or any other core wood or foam, for that matter) unless you really enjoy repair work, but in open water, it would be fine with the proper skins laminated to it. If you were to strip up a hull and leave it on the forms before glassing (any wood you choose from the suitable selection) it would be no problem to walk up and punch your fist right through it. However, when you combine that wooden core with two fiberglass skins, which by themselves only have about as much thickness and stiffness as a plastic milk jug, you get a total package that's surprisingly durable and which will survive a pretty good impact and a fair amount of abrasion.

Different folks have differing ideas of just how strong a canoe or small boat needs to be. Strippers in general don't tend to be the kind of boats that make sense to beat down shallow rocky rivers. They offer light weight, reasonable strength, beauty and good hull stiffness in return for a little bit of care and good judgement. From what I've seen, changing the core wood, between the typical possibilities doesn't make a whole lot of difference in any of those categories or in general durability. The extra reinforcemnets that I've done on redwood-cored strippers would have been done just the same if I had used cedar or spruce instead. The big canoe above has a tapered buildup on the lower stems that winds-up being eight layers of 10 oz. cloth, inside and out at the stem bottom. This was not done because it was redwood, but because a canoe holding five or six people and their gear moving at four knots has some serious momentum if you hit one of those boulders that they hide just below the surface up in canoe country. The rock isn't going to break and switching to a cedar or spruce core isn't going to change that a bit.

[TomMcKinney]

Thanks for responses. Looks like it should work for the intended purpose building a dink thats not a waste of time and learning about strip building. While as a percentage the wieght will be increased in absolute terms it won't be too bad.

BTW Todd that is some amazing work, nice job

Thanks again
Tom

[seo]

I've worked quite a bit with redwood back 35 years ago, mainly on porches and decks. Some of that work was repairing old decks built in the '20's. It was striking how much different the old wood was than the new wood we were putting down. Stronger, less likely to split, harder (more resistant to foot wear). Even within a lift of lumber that we'd get from one yard, there seemed to be a lot of variation.
The point being that I don't think it makes sense to condemn or recommend a wood for any particular use (redwood is good (or not) for this (or that). To a certain extent it depends on the actual lumber you've got in your hands. Some's better than others, just like all the kids in one family aren't equally smart or pretty.
I think that L.F. Herreshof named redwood as one of the suitable woods for use under canvas on the deck of an H-28.
seo

[Spokaloo]

One other facet to this...

If its at least relatively close to the strength you need, and the usability, then what does it really boil down to?

AVAILABILITY!

If it is available, use it! The worst possible outcome is learning.

E

[LeeG]

http://www.catchacanoe.com/

[JC 72]

Tom, How old is that shed? I've got to agree with Seo. I've worked with alot of old redwood and some of the best of it is, just as he said, like a different spieces. The wood I'm refering to was 3/8" x 3" battens from a 1916 brown shingle farm house. This stuff is a deeper almost brown color. The grain in it is so tight you can't readly see the rings. I made an off cut on a piece 1/2" x 3" in lenght across the grain. It took both hands across my thigh to break the piece. Then I took a 8b finish nail and just drove it through one of the bits. It didn't split. Granted your shed siding is not going to be this quality, but my point is some of the old growth heartwood is possibly usefull, and much stronger than one might assume. John Carlson

[Todd Bradshaw]

Unlike those guys, when I say "Catch a Canoe" I'm not kidding. I'd love to try one of those outriggers.

http://www.imagestation.com/picture/sraid216/p0a03faf31006741b131b87e1a8af7f6b/ec880ef2.jpg

[LeeG]

Todd, I forget the guy who makes them, some of the design is a bit spacey/rocket ship like but the general theme is very low wetted area with a high and dry canoe. It's all redwood strip.


I'm out of touch with the CatchaCanoe guys but they're good folks, Big River is a nice place to paddle.