10-foot okoume sheets?

[almeyer]

How hard is it to obtain 10-foot long sheets of okoume, 4mm and 6mm? I'm studying the plans and the book for a Walt Simmons 17' lapstrake canoe, and debating going glued ply versus traditional wood construction. The "real wood" would look nicer, and I think I'm up to the challenge of clenching all those laps and steaming the ribs, though glued ply would be easier as I'm already familiar with that technique. But a 17 foot canoe would require some short scarfs if I use 8 foot sheets of ply, which I'd like to avoid.
Thanks for your help.
Al

[SandMaster]

How are you planning on avoiding scarfs on your 10 foot ply for a 17 foot boat?

[almeyer]

The thought is that if I can get 10-foot long sheets, I'll have one scarf per plank. That's alright. But if I go with 8 foot sheets, most of my planks will have two scarfs, with one being either very short (probably not a good thing), or space the scarfs out more evenly and waste a lot of wood.

[Steve Paskey]

No problem at all. For example, Harbor Sales in Maryland has 5 x 10 sheets of marine okueme in stock, in 3, 4, 6, 9, 12, and 18 mm thicknesses. See: www.harborsales.net (http://www.harborsales.net)

[JimConlin]

There's another approach which might be more work than everyone would be up for, but which can produce a nice result. Veneers are available in lengths of 10' and longer and permit using a species not available in plywood of boatbuilding quality. If you want 1/4" ply, scarph up long sheets of 1/8" ply and vacuum bag 1/16" veneers onto it. Run the grain of the core sheets cross-ways.

[SandMaster]

This method may be less work than Jims and also yields some nice results. Best of all no scarfing! ;) http://www.n2allnations.org/Burning%20outside%201.JPG

[Keith Wilson]

Actually, it's not bad to scarf to that length. I built a canoe of about that size out of 5mm okoume plywood with two scarfs per plank. I cut the 4x8 sheets in halves and quarters, so the planking stock was 20'x 2' panels, composed of two 2x8s and one 2x4 (feet, obviously). Four 4x8 sheets will give you three 20x2 panels (minus the scarf lengths) , with a 2' x 4' bit left over. Just make sure to reverse the sheets every other plank so that the scarfs are staggered and it'll work fine. In fact, the 8' sheets might actually be better; there is something to to be said for not having all the scarfs right in the middle of the boat. Anyway, if you can't find or don't want to use 10' sheets, or if the 8' is a lot cheaper, it's an entirely viable alternative.

[ 08-23-2005, 09:41 AM: Message edited by: Keith Wilson ]

[Venchka]

Yup. What Keith said. A whole gang of 15', 18', 19' and nearly 20' Iain Oughtred double enders have been built with 4'x8' sheets of plywood. Just do some juggling so the scarfs are in areas of little stress and at least a foot apart in adjacent planks. More is better of course.

Wayne
In the Swamp.

[ 08-23-2005, 10:08 AM: Message edited by: Venchka ]

[Lurch]

Al, I already posted this on your other thread, but try calling Houston Hardwoods. (http://www.houstonhardwoods.com/index.php) They carry okoume, but the site doesn't give sizes or prices.

Don

[Venchka]

This might help you decide. Using Harbor Sales' prices:

5'x10' panels: $3.08/sq. ft.
4'x8' panels: $1.81/sq. ft.

Wayne
In the Swamp.

[ 08-23-2005, 11:53 AM: Message edited by: Venchka ]

[almeyer]

Thanks for all your responses. The difference in cost per sq ft pretty much knocks out the 10' ply panel option. I called Houston Hardwoods, they only have 8 foot sheets. I also asked about white cedar, which Walt Simmon recommends, and they don't carry it. Red cedar would be an attractive option, but Greg Rossel's book states that it's more brittle and not as strong as white cedar. I'll do some more looking around, but it looks like it's going to be okoume with two scarfs per plank.
Al

[Venchka]

The white cedar is in Florida. A load passed through Houston headed for Austin about 2 weeks ago. Go to Florida and get some. Or do like Paul Gartside does: build clinker boats with red cedar because it works, he is knee deep in it and he didn't read the same book.

PS: All those folks in Maine are spoiled. If they lived in Seattle they would say, "build with red cedar."

Wayne
In the Swamp. :D

[ 08-23-2005, 09:34 PM: Message edited by: Venchka ]

[Bill Perkins]

If we accept that the scarfs are full strength and bend fairly ,and that AL's scarfs will be barely visible : it seems more logical to glue up the first plank with 3 eight foot pieces ,cutting the glue up to length after scarfing . The next plank would be glued up with two 8 ft strips and the cutoff from # one , and so on .This would minimize waste .

[ 08-23-2005, 11:48 PM: Message edited by: Bill Perkins ]

[almeyer]

Or do like Paul Gartside does: build clinker boats with red cedar because it works Good call, Vencka. I e-mailed Walt Simmons asking about alternatives to white cedar. He responded very quickly and mentioned several options, including red cedar.

[RodB]

On my 18 foot skiff with 24" high by 18 foot long sides...the designer specifically suggested not using the 8 feet of length of the plywood sheets and instead cross cutting shorter pieces and then gluing them up... in order to achieve a much stiffer side panel. He felt the added stiffness was well worth the extra work.

I cross cut the 3/8" Okoume plywood sheets into 5 pieces of 48" X 25" and then scarfed them together with my John Henry Power planer attachment (see classified section in WB Magazine) . The results was four scarf joints per side... and a very stiff and uniform/fair side panel 25" X 18' for my boat. The bottom panels were done the same way. The power planer attchment makes perfect scarfs possible every time and the cost is quite reasonable. The Makita power planers are easily had both used (pawn shops) and new...and the money saved from not buying the 10 foot long ply would easily pay for a power planer and the scarf attachment with lots of money left over. Additionally, a Makita power planer is also a great added tool for the shop when not scarfing.

RB

[ 08-27-2005, 08:36 AM: Message edited by: RodB ]

[almeyer]

Thanks for the suggestion, Rod, I'll mull it over some more. Right now I'm leaning towards going with traditional construction, partly for the challenge and partly because I like the look better. Though I certainly can't complain about glued lap - my Penobscot 14 came out looking pretty decent. It's nice to have both options open.
Al

[RodB]

The beautiful and "very strong" Albert Strange's "Wenda"...."Sally" comes to mind. Jake built her glued ply lapstrake with 1/2" Sapele ply and ended up with a very strong and rigid hull that is optimal for trailering. Just a thought.

Glued ply lapstrake Albert Strange design (http://www.woodenboat-ubb.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=011592)

[Thad Van Gilder]

I put some clear aramatic red cedar on the cross planked bottom of a 12 foot skiff some time ago, and last I heard, the kid who owned the skiff is still crabbing off it up the Tuckahoe river.

I dunno If I would use that stuff for planking with much bend, as it is very stiff, but it did ok, and it is very, very cheap around here... unless it has already been planed and labeled closet lining. Then it's expensive.

-Thad