SOF Canoe - Bamboo for ribs

[Songololo]

As an alternative to wood for rib material in skin-on-frame canoe/kayak construction, some builders have been using bamboo. The 'bamboo' that is often talked about is a manufactured bamboo product referred to as carbonized vertical bamboo. So far I have not managed to find out any details of what specific bamboo product (there are various thicknesses and types) is actually being used or how it is cut into ribs.

What I'd like to know is:

• what bamboo species would be suitable for steam bending
• what is the original thickness of the laminated bamboo product (they come in various thicknesses depending on planned usage e.g. 0.6mm, 5mm, 20-50mm) before ripping into strips?
• what should the orientation of the bamboo layer(s) be in the cut rib strips?
• are ribs which include glue lines acceptable?

An Australian builder of the Cape Falcon F1 kayak has sourced material from Bamboo Australia. The rib size for this kayak is 1/4'' (4mm) x 7/8'' (22mm)



So far I have found out that vertical refers to bamboo pieces laminated in this orientation (image on the left):




And horizontal refers to bamboo pieces laminated in this orientation:




Has anyone had any experience with using a bamboo product as rib material in an SOF kayak/canoe?

[Wooden Boat Fittings]

No. But I've used it as flooring material. As you show, depending on which way the bamboo is split you get to see the nodules every so often, or you don't. I preferred not to, and this was the result --

As used, this is essentially a floating floor, t&g on sides and ends. But because it's solid (not just veneered) it could satisfactorily be used over joists and bearers. No glue lines are visible on the surface, but of course if you laminate boards together as we did for stair-treads, then they are --

The material itself is resin-bonded, and rather heavy, but I imagine in the sizes necessary for a canoe would still be satisfactory. It's available as flooring (in which case it's 5/8" thick from memory,) or as furniture board that comes in a variety of thicknesses (as the second photo shows.) If you were ripping strips from a bamboo board I suspect you'd find it pretty tough on your tools.

We sourced our bamboo from this crowd, and found their assistance with advice fantastic and their prices very reasonable.

Mike

[Jay Greer]

Of course, the Chinese have been using bamboo in boat construction ever since the building of the Great Wall for battens and spars. I should think that one would want to begin with lamination of raw stock rather than resin impregnated planks in order to facilitate easy bending especially if steaming is needed. However, bamboo is a grass and not a wood. Taking that into consideration might place it rather low on the scale of rot resistance. Just as the man who ate the first raw oyster, he who first tries bamboo as framing stock may either be a brave genious or a damn fool depending on the outcome! I say, go for it and let us know what happens.
Jay
One hint, bamboo can be easily heat bent over a hot pipe.

[David G]

The major importer to the U.S. is PlyBoo. This material comes in 4' X 8' sheets, like plywood. It's available in several configurations of layup, including the 'vertical' you show. It also comes in two colors - a natural, and a dark. The dark is a carmelized product with the color coming from response of inherent sugars to heat. While I like the looks of the dark better, I'd suspect the natural might be stronger. I've used it for architectural millwork many times. My experience, though, is that the gluelines are not always perfect, and the glues used are not always waterproof. I'd be quite hesitant to use it (other than decoratively) in a boat without a good bit of testing.

[Songololo]

Hare are some better images showing the different bamboo floor board types:


Horizontal:



Vertical:



Strand woven:

[P.I. Stazzer-Newt]

I am baffled as to why you would want to use laminated bamboo as ribs, rather than simply splitting the natural stock.

The "carbonized vertical bamboo" is a manufactured product which is actually softer than the natural material - all they have done is high pressure steam it before glueing.

Bamboo is readily available in the UK in 5.5" (140mm) diameter - that's 17.5" (440mm) circumference and ten feet (3m) long - about £15 per pole in small quantities. - That's an enormous pile of rib material. It splits by hand fairly easily and bends readily with dry heat - hand tools and heat are used for the nodes (check fishing rod building instructions - http://www.thomaspenrose.com/tonkin.htm).

http://www.bs-bamboo.co.uk/bamboo_extra_wide.html <<< UK supplier.


You planning to dry-store the boat?

[Jay Greer]

Lamination would only be needed if the natural stock produces material that is too thin in scantling once split.
Jay

[Tom M.]

I use it all the time for SOF kayaks, and it works great. I get it from a fellow in Portland, OR. 6mm sheets, carbonized, vertical laminated. That said, its not always the best choice. I use it because its cheap and easy to get a lot of rib stock, and the 6mm dimension is perfect for my 22 inch beam boats. It does not bend as well as oak, but its good enough for me to get the shape I need.

Pros: Cheap, stiffer than oak, bends well enough, and cutting from a 4x8 sheet means there's very little waste. In contrast, its always a bear to get good white oak, plus its so much more work to get a good rib with oak, with much MUCH more waste.

Cons: It can be fussy to bend. I've noticed that 15 seconds either way can make the difference in the steam box. Experiment. I don't think its suitable for framing a boat much wider than a kayak because its only 6mm thick.

I've never experienced rot, but then again, I use it to frame kayaks without bulkheads, and there is very good ventilation. If I was building a "regular" boat, rather than SOF, I would not use bamboo for fear of rot. But since a skin on a well used SOF will last about 5 years before needing replacement, I feel that the frame will be inspected at that time, and new framing members fitted if necessary.

A bit of trivia, the fellow at nwbamboo.com, where I get the stuff, told me Kiliii Yu was the first to experiment with bamboo for SOF kayak ribs a few years ago. So, props to Kiliii.

Another bit of trivia: Brian Schulz, the fellow on the Oregon coast who teaches SOF boatbuilding classes, used bamboo for a few years until quality control became spotty, causing steam bending problems in his classes. So he switched back to white oak.

[David G]

Tom,

I think it's cool that people are experimenting with various materials, tools, and techniques in their boatbuilding. I applaud the intrepid innovators. Based upon my experience with the material, though, I suspect you'll decide (as Bryan did) that this version of bamboo is less than optimum. But... hey... I've been wrong before.

[The Bigfella]

I saw an interesting house constructed of laminated bamboo, somewhere in Flores. There was a whole heap of tech data on info boards, but my photos of it didn't come out very well (it was faded)

[Tom M.]

David, I think white oak is optimum. But you seem to think bamboo has not passed the test. Its been tested in probably at least 500 kayaks between Kiliii and Brian. There are a LOT of well used bamboo framed SOF kayaks out there. Brian switched back to WO not because bamboo was inferior for his purposes, but because his classes ran more smoothly when WO was used, due to some bamboo sheets being 7mm, some 6mm, etc. He didn't want to deal with the guesswork with 5 paying students on a timeline. If you ever witnessed Brian's operation, you'd understand...its production.

I use WO for the tight bends forward, bamboo everywhere else. Its economy is undisputed. For about 80 bucks you get enough ribs for five SOF kayaks by simply ripping it on the tablesaw. And it works very, very well. I carefully check its thickness, and plane it down when necessary, a luxury Brian can't afford in his situation.

Again, I would not use bamboo on a non-SOF boat for the reasons I stated above. I also don't recommend the 6mm for a flat sectioned boat wider than about 24 inches.

Oh, one more thing. I've built about 20 kayaks with bamboo ribs. No problems except for the machine in China spitting out slightly different thicknesses, always erring on the thicker side.

[David G]

Tom,

My hesitation comes from seeing such a wide variety of quality control in the manufacturing of the panels. Beyond the thickness variances - I've seen many panels with splits and voids. In addition - my backyard testing of the weather resistance also showed a wide variety of results. Some was still going strong after 2+ years, and some delaminated after the first soaking. I'm not a S.O.F. guy (though I have two frames hanging on my shop wall - awaiting completion) so I'll bow to your experience, while holding onto my bit of skepticism over the long haul <G>

[Tom M.]

It splits very easily, yes. But a 1 inch wide rib doesn't, and even if it does, it wouldn't matter much in a traditionally framed SOF kayak. Ya gotta take these things in their physical context after all.

I'm curious about the voids you've seen. Can you explain more? Was this void in a vertically laminated sheet?

I know for a fact that bamboo framed SOF kayaks have regularly taken ferocious beatings over several years in the Pacific surf. One broken rib that I've seen, and you had to look for it. The boat performed the same, and was perfectly safe.

[David G]

Tom,

I've used most of the layup configurations. The worst voids seem to be in the type that has a vertical core and horizontal faces. Almost all of the material I've processed is the 3/4" (18mm?). Yes, I've seen voids in the vertical sheets. The worst was a batch from nwbamboo, but I've also seen it in sheets from Plyboo, IIRC. My experience with nwbamboo, btw, has been mixed. It seems like each shipment he gets is from a different supplier/mill. Some of it is great, some is awful. We now pay the premium for the more consistent quality control that Plyboo seems to invest in.

[Tom M.]

Interesting. I think I'll look into Plyboo. Thanks. I've stayed with nwbamboo because I didn't know of any other supplier that's close. I've just used the "6mm" vertical laminated sheets.

[David G]

Tom,

Another possible supplier: Lumber Products, who delivers in your area, IIRC, has - in the past - also carried it. I have no idea who their supplier is these days.