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Plywood Skiff Guys?


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#1 The Lure Washer

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Posted October 09 2009 - 3:06 AM

I know Ive posted asking questions and there was a recent thread that put the bug in me again. So a couple of questions to those of you that have built them. Can I get plywood at say Lowe's or Homies? Also Is marine grade plywood necessary or can I use exterior grade? Also I read somewhere that painting it with copper fused paint is crucial to keep marine parasites out of the wood? Is that really true or will any marine type paint do?


BranfordJeff - I'd hit it like a drumset in the special ed classroom.


#2 Chief2

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Posted October 09 2009 - 7:33 AM

not a plywood skiff expert, but I built an 11' hydroplane type boat out of plywood. Used 1/4" exterior grade, and covered every board with epoxy, efficiently sealing off the wood to any water. This is probably very expensive for you, but I did it at boatbuilding school as a side project, and we bought 50 gallon jugs of epoxy and paid cost, so it wasn't too bad. I would tend to say that the reasoning behind the copper-based paint, because pressure treated wood is now done with a copper product. If you are not sealing every board of wood, either with an epoxy-based paint, or some form of resin(polyester, vinylester, etc) I would tend to thing a copper paint wouldn't be a bad idea.

My boat has been out in my back yard for 7 years, not a spot of rot, or evidence of a single bug.



#3 PeterJ

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Posted October 09 2009 - 8:37 AM

I think it depends on what you are building.
I built (am building, it is a typical boat project and it isn't done) a sea kayak and it is all marine grade plywood.
My understanding is that marine grade will not have voids in the laminate material, letting you more constantly bend the sheet. In a sea kayak, there are reverse curves and long running curves. They all came out nice and smooth with marine grade.
Standard lumberyard ply most likely will have voids, and I think the issue is that you may have issues with tighter curves or just there look.
I don't believe it is an issue with longevity.
My boat is sheathed in fiberglass cloth and epoxy. There is no exposed wood, it's all under something.
If you google stitch and glue construction you'll find a lot of good stuff about simply plywood boats.



#4 The Lure Washer

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Posted October 10 2009 - 1:34 AM

Im just wanna build a brockway skiff. Stitch and glue is a little out of my league, I think! I was under the impression that the brockway skiff wasnt stitch and glue.


BranfordJeff - I'd hit it like a drumset in the special ed classroom.


#5 robc22

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Posted October 10 2009 - 4:05 AM

Hard to beat stitch and glue. I comm. shellfished plywood skiffs for years. Never let a little ice at the boat ramp stop me either. I never painted my boats But used solid stain.....It just slowly faded and when I came time to redo there was no scraping of old paint.



#6 Wild Ryan

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Posted October 10 2009 - 5:31 AM

I have built a few custom made boats and on something as small as a 14' to a 18' skiff you are better off spending the extra money.

Also, I'm a union carpenter, and have a pretty nice shop for my crafts.

My reasons for using the marine plywood are this, exterior grade A plywood may look veneer wise the same, but it isn't.

Example:

Marine plywood:
1/4" 4-5 plys (veneers)
3/4" 9-11 plys (Veneers)

Exterior plywood:
1/4" 3 plys
3/4" 5 plys, maybe 7 if your lucky

Exterior glue have alot to do with it, but plys or veneers are were plywood gets its strength. Crossing of grains in the veneers.

Back to the skiff, the difference in the cost of plywood for marine vs. exterior is roughly $70 per sheet at about 5 sheets that only $350 which in my opinion is cheap compared to the fact your boat will be stronger, better looking and yes, last many more years.

PM me, I have plenty of info I could send you and places to get marine plywood at market not marina prices.

I'll be building a 18' Carolina Dory this spring for my son (With him) for his 16th birthday. I will be putting on an 40 hp E-tec which should last him till he has enough cash to buy what he really wants (vintage bertram in the 28'-31' range).

Hope this helps.
Ryan

Also added, stitch and glue is not that hard. I think it's easier then mechanical fasteners and stronger.


Hey Bert!
Dare to Differ!

#7 Chief2

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Posted October 12 2009 - 8:07 AM

IMO, I don't think stitch and glue is easier than fastener securing. That being said, I don't think it's any harder either. Little more expensive, but not necessarily hard. Builds a quality boat.

GL with your build.



#8 Wingnuts

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Posted October 12 2009 - 8:22 AM

I agree with Ryan, I would use marine grade over exterior as the plys and adhesives are different. The marine plywood will last you much longer!


The early bird gets the worm. But the second mouse gets the cheese!

#9 Shag

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Posted October 24 2009 - 5:22 PM

Robc22


Quote:







I never painted my boats But used solid stain.....It just slowly faded and when I came time to redo there was no scraping of old paint.




I used cuprinol stain when you could get the good stuff and did the same thing to the interior of my skiffs. I had gell coat in the resin of the fiberglas
on the exterior never had to paint that either.



#10 robc22

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Posted October 24 2009 - 5:46 PM

The plywood skiffs were great. If you had to rig them for bay scolloping, jet-clamming or just plain bullraking they were hard to beat And the price !!!! could not be beat........