Wood duck with super strong hull

I am thinking of building a WD12 HB with a hull that can take a beating.  Is it possible to make the hull out of 6mm plywood or is that too stiff to bend?  I would like to cover it with kevlar instead of fiberglasss - is that doable?  What else could be done to make it stronger and more durable? 

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RE: Wood duck with super strong hull

the existing design is plenty strong......so it depends on what do you mean by 'taking a beating'.

if you mean take any kind of sea and hold itself together....you can stick with the existing design and perhaps, at most, double up the existing layup (one layer of 4 oz cloth becomes 8 oz of 4 oz cloth).

if by strong you mean to be dragged up a beach -- dynel or brass rubstrips on the keel line work well....but even these are sacrificial to some extent and as you wear through the rub strips...you will need to replace them

if by strong you mean to be bashed against rocks.....i would ditch the wood duck and go with a plastic boat.   kevlar, glass, etc....used in this kind of construction.... is simply not designed to be dancing on rocks.  it is simply too stiff and easily abraded and will look all torn up and ugly pretty quick.

hope that helps...all the best



RE: Wood duck with super strong hull

As Howard said, it depends on what you mean by strong.

On my WD12, I was interested in abrasion resistance, impact strength and the strength to hold together in rough conditions. I did 2 main things.

First, I paid a lot of attention to workmanship. Not the cosmetic type which wins the best in class, but the actual structural workmanship that gives you a strong boat.The fillets are small, just large enough to do the job. There was just enough epoxy to wet out the glass and fill the weave. There are no bubbles in the joints or the glass. The result is a light structure with a high strength to weight ratio and no voids to act as stress concentrators or starting points for delamination.

Second, I covered the entire boat, inside and out, with 4 oz woven glass, That provides good abrasion resistance, better resistance to impacts because of the internal glass and a more uniform encapsulation than using just epoxy.

In addition, I also replaced the end pours with roughly shaped pieces of wood bedded in epoxy/woodflour putty. That saved weight and put a less brittle backing at the bow and stern. Also, on the bottom, I filled the weave with phenolic microballoons and covered it with epoxy/graphite mix. This made for a lighter boat and a slippery, easy to repair bottom that resists scratches.

It worked out fine. The boat is over 7 years old and still going strong. It's been in seas so rough that I could feel it flex as it went from one wave to the next. It's been dropped, beached on sand, mud, gravel and concrete. It's bashed into wood and aluminum piers.

You don't need to get exotic and you don't need to add weight (my boat came in 1 pound below the catalogue design weight, even with all the extra glass). Extra weight just makes for a weaker boat. The WD series is a strong boat as designed and doesn't need heroic measures to make it extra strong.

Have fun,



RE: Wood duck with super strong hull

Plus, you can't sand Kevlar, which takes half the fun out of building a wooden boat...

RE: Wood duck with super strong hull

Rather than beefing up the wood component of your boat, if you want to make a stronger boat do the opposite. Use 3mm ply (or cedar strips for the hybrid part), and sheath the exterior with lots of glass, 3-5 layers of 3.25oz tight weave works a little better than a single layer of heavier cloth. Then sheath the interior with a higher modulus cloth like carbon or kevlar, just one layer of ~6oz cloth, no glass. People have built whitewater boats using this recipe.

You may have trouble getting much clarity through all the glass, and need to paint.

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