Thomas,
My only kayak is a tortured plywood "Yare". It's made from 3mm Bruynzeel and only has a double strip of 3" 'glass along the keel. I try to stay away from shallow areas and usually mount and dismount in knee deep water to protect the bottom. The upside is 35lbs. total with all the hardware mounted. It's a pleasure to cartop.
Epoxy will degenerate if exposed to too much sunlight. It has to be covered with paint or spar varnish. If the ply is pretty varnish will show it off. If the ply is from a bigbox store I use varnish anyway to expose the black spots where microbes are munching on the wood.
Since you seem to know where you're going I think my comments were unnecessary.
Good luck.
Charlie

: As if ya'll had nothing better to do than read my ramblings, here's another
: huge procrastinating-because-I-don't-want-to-do-any-real-work post!

: Remember that movie "Friday"? The guy walks into Smokey's bedroom,
: stares around, and says "Damn, Smokey! All you DO is smoke
: weed!" Well, I feel like that about kayaking and building these days.
: "Damn, Thomas! All you DO is think about kayaks!"

: And Guns N' Roses said: "I used ta do a little but a little wouldn't do,
: so the little got more and more, I just keep tryin ta get a little better,
: a little better than before."

: Somebody please help me! Why oh why did I ever build that first boat? I was
: warned.

: Anyways... in response: True that. My luan has about a 4mm core which I think
: is oak (!) and two veneers about .5mm each.

: I fully intend to glass inside and out. I couldn't see doing it any other
: way. I believe the resulting composite sandwich will be plenty strong
: (gonna find out) but I am already preparing myself to take a big weight
: hit for it. I'm doing this boat mostly cause (1) I want a boat with a low
: Greenland-ish sheerline and volume to work on my rolls and because I find
: that shape particularly pleasing, (2) I want to get a low-cost experience
: of building from offsets, and (3) I miss being out in the hoophouse
: building. My WD Anuri 16 will probably remain my primary boat for short
: after work paddles etc., cause it is much lighter than my plastic boat and
: easy to cartop and a heck of a lot more comfortable, better fitting and
: better paddling. No doubt okoume is the best and lightest for the S&G
: method.

: Regarding strength, I had scraps of 4mm okoume still laying about, and I cut
: some pieces about 2" x 7" this morning of both the 5mm luan and
: the okoume. The uncoated okoume snapped easily and cleanly between my
: fingers and thumbs, but it bent smoothly a long way before snapping. The
: uncoated luan took about twice as much force to snap, but when it went, it
: went at all at once without nearly as much bend, and 2 out of 3 bent
: oddly--off to the side of my thumbs, one piece more "crushed" or
: collapsed then broke. I think that was probably a small void that didn't
: go all the way across. We'll see how construction bends go. I don't think
: I will have to make many hard bends, and if I do, if it's bending weirdly,
: I am inclined to score the backside of the bend a little--rows of shallow
: cuts with a razor knife or coping saw--or maybe try some heat to get it to
: loosen up.

: I'm anticipating wires wanting to tear out already, and hoping to offset that
: by drilling further away from the edge and using more wires in stressed
: areas.

: Re price, I bought five sheets of 4x8 luan for what one sheet of okoume would
: cost me, not counting shipping. Figure I saved over $200 bucks in wood by
: the time I paid shipping. For the purposes and reasons I'm doing this
: build, I figure I can live with that, especially with Christmas coming.
: And I have a full 4x8 and a half left for screw ups (or maybe to build a
: tuna tower) after cutting the blanks for the panels. I'm going to save
: $20-$50 more by using Raka epoxy and glass vs the West Systems I used on
: my WD boat. My estimates put this boat at about $450, not counting
: sandpaper (I'll have to buy at least one box of discs), and any other
: consumables. I've got most of what I'll need for rigging out already. I'll
: make recessed fitting from scrap paddle wood, and may forgo bungies in
: favor of lines with sliders. I have some mincell foam left from my last
: boat, and am thinking of stripping together a seat pan from scraps like I
: saw on someone's website, then padding it. I probably spent over $1500 on
: the WD by the time I finished. I glassed the hull inside and out, and
: mostly glassed the bottom of the deck, and all over the top. I used a half
: gallon more epoxy than came with the kit that first time. This time I will
: do a saturation coat prior to glassing, in hopes that it will cut back on
: epoxy and give a better lamination. Of course, with my luck, the luan will
: soak epoxy all the way through and wind up being a 100lb. boat and I'll
: have to buy an extra $200 worth of epoxy. Time will tell.

: My luan explicitly said "water resistant" on the shelf label in HD.
: I reckon since I am going to completely encapsulate it in epoxy it won't
: matter unless I gash it deeply. In which case I'll probably end up cutting
: out the damaged wood and patching it. I'm gonna paint the hull black on
: this one, and will likely use graphite in the epoxy on the keel and what
: would be the "football" area to stave off the oyster beds from
: tearing into the tender innards.

: I'm guessing my luan weighs close on 20lbs per 4x8. I may be building a
: battleship! We'll find out! Maybe jet skiers will think twice about
: running over me ; )

: I also got in the habit of using short partial pumps to make sure I had the
: tubes filled with resin before giving it a full stroke when I used the
: West Systems last time--after I had to toss a batch when the pumps gave a
: big burp and I got all discombobulated. But otherwise they worked really
: well for me as long as I was careful to prime the pump. Every batch kicked
: off as expected. I asked re the Raka pumps, because I think pumps are
: mighty convenient, but they are $13, and if I need to double check with
: measuring cups, I might as well get a couple free syringes and just do it
: that way. I'm trying to scrimp on costs with this one. Not cause I have
: to, but cause I want to beat the system. I want to paddle out Bogue Inlet
: into some 6 foot swell beside my buddy in his $3000 NDK boat and know I
: built mine for less than $500. (And hope he has his tow belt so he can tow
: my busted up cheap luan piece of crap back to the beach! ; )

: Sometimes the impulse to save money makes things heavier too! Oh well, I can
: still excercise light principles with the epoxy and hope for the best.
: That's interesting about finishing with varnish. Didn't know that. Do you
: mean varnish over epoxy, or just on the wood? Do you glass? Or just tape
: and glue?

: The big

: I used *way* too much epoxy last time. My hull fillets were 2-3 inches wide,
: and bumpy as heck towards the bow and stern. Which I "fixed" by
: mixing up a 16 ounce cup of epoxy and cabosil and pouring it down the keel
: line inside the hull. I adjusted the angle every so often so that it
: flowed out smooth and covered the lumps from a crappy fillet where the
: hull squeezed in approaching the bow and stern. I had to repeat this on
: both bow and stern a couple times. Finally, I had this big
: "glacier" of thickened epoxy on both ends, leading to gigantic
: end pours. Bet I added at least 5 pounds if not more, and I might have
: some of the most expensive end pours around. But it made a smoothy-smooth
: job of glassing the inside, didn't have to glass down into the
: "crack". Not advisable that anyone else do it like that! I also
: made a gargantuan wear strip on the keel. Cutting strips of glass from the
: cloth was just too frustrating with all the little threads pulling off the
: edges, so I used layers and layers of 1.5" tape to form a bumpy and
: thick keel strip. Another 5 pounds probably, and it was the very devil to
: sand smooth. I ended up making more fairing compound of epoxy and cabosil
: and microballoons to fill the valleys. I'm confident that I won't do that
: again!

: This time around, I will probably shape some Dow blue foam to go in the end
: cracks and down in the keel line where it gets narrow. Paste that in with
: epoxy and glass over it maybe. Fill the space without the weight. WD sent
: wedges of foam in their kit to make lightweight end blocks with, but I
: used them as wedges to hold the boat at an angle while I taped the inner
: sheer line.

: Sure I'll make a whole new set of mistakes this time around, but hopefully
: I'll not make the same ones again. But maybe I'll get a bigger rush out of
: this one!

: Hopefully it won't be a rush to the ER when I put my back out trying to lift
: it the first time.

: It does help, and I appreciate your time to respond. You're confirming some
: things I've heard before and teaching me a couple things. I now figure my
: luan weighs more than twice okoume in 4mm, and I never new about the
: varnish finish water spot thing.

: If you're still reading, I apologize for the long post. Besides keeping me
: from dreaded work, writing this stuff out helps me to think things
: through.

: TD