Is okoume my only choice?

I'm trying to execute some repairs on my brothers kayak. First let me say this, I have never done any boat building or worked with epoxy. I have a kayak kit that I will be starting after I fix up my brothers.

Ok, the coaming lip has deteriated and started to delaminate. So I pulled it off. I think the veneer layer that was glued to the coaming riser stayed, but I don't think that should matter, correct? The riser seems to be in good condition. So I plan to reuse it. Now my question, do I have to use okoume? or are there other plywood options for me? (like ones that I may be able to pick up at the local home center) Also, what is the best way to create a pattern for the coaming lip? The lip came off in MANY pieces. Then, do I need to fiberglass the lip?

Maybe a little more about the boat.  It is a custom design, around 15 years old.  It is 18' long, and about 28" wide.  (It's a big one)  Hard chines and arched deck.  I would say it is similar to a chesapeake 17.  From what my brother told me, the person who built it was had never built a kayak before.  It shows, the supports around the hatches were way undersized and very poorly glued to the underside of the deck. (I plan to replace those too.  That may be another post later.)

This is getting away from my original questions....do I have to use okoume? method for the pattern, and fiberglassing.

Thanks in advance.


13 replies:

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RE: Is okoume my only choice?

Jerry...about the only similar wood you would find at a home centre would be luan plywood but it's probably not suitable for the abuse the coaming lip will be subjected to - too many interior voids etc.  http://www.clcboats.com/shoptips/stitch_glue/lauan_plywood.html I would stick to 6mm okoume for best results. CLC sells half sheets which is all you'll need: http://www.clcboats.com/shop/products/supplies/plywood_cedarstrips/0000-OP000.html

As far as a pattern, I would lay a piece of cardboard over one half of the cockpit opening along a centre line string and trace the contour onto the cardboard from underneath.  This will give you the inside opening shape.  Then take a compass and set it at the width you would like the lip to be.  With pin side of the compass trace along the inside line you have already drawn.  The pencil side of the compass will give you the outside contour.  You may have to freehand some of the edge contour if the present opening has a keyhole design like the Chesapeakes have.

After tracing with the compass scibe cut our your pattern you now have a half pattern to use to trace onto your plywood.  Just flip the half pattern to trace the entire opening on you sheet.

After you install the new lip (use lots of clamps), I would cover the entire inside and top edge of the coaming with 4 oz. fibreglass and epoxy.  It goes on real easy and provides a good deal of protection from the knocking and banging from getting in and out.   

Hope this helps.

Chris

RE: Is okoume my only choice?

It is a huge help...thank you very much.  Now I wish there was much closer supplier of okoume...it seems such a crime to have to ship only a half sheet all the way from CLC to the midwest.  (Not to mention the cost!)

 Jerry

RE: Is okoume my only choice?

The shipping costs are probably not that much and they can probably get it to you pretty quick too.  I have wood (full sheets) shipped from Toronto to my place and it's here next day.

RE: Is okoume my only choice?

Okoume is not your only choice, at all. Marine plywood comes in a number of woods - like Meranti, Sapele and yes, even Fir (to name a few). Some is better than others, but realistically, you don't even need marine plywood.  Heck, if you sort through some stacks of 1/4" exterior plywood at a lumber yard, you can often find wood without voids, are at least none where you cut out the coaming. I have done this in the past, and the results were just fine.

BS 1088 marine plywood has more plys, and no voids. It's the best. Personally, it is my first choice - though I prefer Meranti instead of Okoume, as it's a bit stronger/harder. But, as long as you have a nice solid bit of (waterproof) plywood for your coaming, you'll be OK - Especially if, in any case, you intend to cover it with fiberglass.

 Just pointing out some options. Good luck!

D

RE: Is okoume my only choice?

Meranti is also somewhat more rot-resistant and costs less than okuome. It's also less flexible and weighs more (neither of which count much for a single coaming lip, but do count very much for an entire boat).

Lumberyard wood is even heavier, less flexible, doesn't cut as cleanly and usually needs a fair bit of filler to make the outer surface smooth. But again, for just a coaming lip you can probably get away with it if you pick your piece very carefully as Dave says.

For an entire boat, though, okoume is the way to go, especially if it has wild curves.

Laszlo

 

RE: Is okoume my only choice?

You should be able to find a supply of BS1088 marine plywood in the midwest though I wont advertise them here on CLC site if you contact me direct through our website I will be glad to help We are located in the upper midwest)

cfoxwoodboats.com

or e-mail me @ [email protected] 

RE: Is okoume my only choice?

I'll have to disagree with ChrisJ on this one and say Luan is a perfectly acceptable choice for all parts of a boat.  You'll have to take care to search through the pieces to make sure you don't have any voids, but that's the case with any plywood, so it won't be any different for any other option you choose. 

 

There are plenty of other options, that will work very well for repairing your brother's boat.  Find the one (others have given better options than I knew about) that suits your needs and your budget the best.  When it comes down to it, once it's epoxied and varnished, they'll all do the job, some will last a little longer than others, but then half the fun is building and fixing so...

 

FrankP 

RE: Is okoume my only choice?

Shipping for plywood orders under 16mm thick is a flat rate of $99.  I am not going to pay over twice as much for shipping than the product itself.  So I will look into the other options.  The biggest challange may be trying to match the color to the rest of the boat.  Or I may just need to make a feature by making it a very different color.  Like black or leave it the natural color.  Guess I need to think about it.

RE: Is okoume my only choice?

My experience with luan occurred through extensive testing my router scarfing jig. I bought a full sheet to fine tune the jig instead of wasting my BS1088. I cut a ton of scarfs and cut through many voids in the luan. Odds are good that there were other hidden voids where I didn't scarf. There were also, for whatever reason, numerous rugged threads embedded throughout the plys of the luan - don't know what that's all about. The coaming lip can be subjected to considerable force as you are entering/exiting the kayak. I'd hate to have a hidden void close to this area. I still think it's wise to stay away from it.....

Chris

RE: Is okoume my only choice?

Frank,

Maybe luan from the past, but none of the luan I've seen lately was ever usable for a boat design of the type sold by CLC. For traditional plywood on frame, maybe (if glassed). For pre-stressed frameless monococque, no way. The wood had 3 plies, the outer 2 being very thin and mostly cosmetic over an inner core. That core had lots of voids and seemed to be made of chunky sawdust. There's no way it could have made the bends needed by CLC boats without breaking and it wasn't strong enough for a coaming lip.

Now that doesn't mean that good luan doesn't exist anymore. I just haven't seen any of it in any lumber yards I've visited in the last 8 years.

Jerry,

If you're up to it (it'll be more work than cutting a piece of plywood), you could make the lip from solid wood. Small pieces of clear pine are still possible to find in lumberyards. You could piece together a blank and carve it down to form the new lip. You'd be trading your time for money, but it would end up a lot cheaper.

For that matter, how much does CLC charge for a pre-cut Chessie coaming lip? The shipping on that should be a lot less than $99. If it would fit your yak that might work out to a low enough price.

Laszlo

 

RE: Is okoume my only choice?

Coaming piece would run about $40.

RE: Is okoume my only choice?

 

We do send out an awful lot of CNC-cut coamings, come to think of it.

RE: Is okoume my only choice?

I had good luck using baltic ply. They also call it Russian ply. Its heavier, not terribly pretty but it is strong and did not delaminate when I boiled it for an hour. Its not always easy to find but sometimes you can get it at the big boxes. Home depot, Rona etc. I never found a void in any of the countless sheets I have used.

 

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