What's in this "composite" constructed skiff?

[anamealreadyinuse]

I noticed on a social media site that MicroDraft skiffs bills their skiff as "all composite" construction but in the pics, this looks alot like marine ply being encapsulated? I'm researching materials and building methods. Is this plywood or is it some sort of alternative material used to achieve the same result?

Here are some of the build images:

 

[jigngrub]

Composite won't rot, or won't rot as fast maybe.

If you like to neglect your boat and leave it exposed to the elements you should consider composite construction.

 

[anamealreadyinuse]

Can you switch out the H60 Divinycell or Corcell with the same thickness as you would marine grade plywood and get the same results? Is it that simple to not have to worry about wood rot?

 

[jigngrub]

Can you switch out the H60 Divinycell or Corcell with the same thickness as you would marine grade plywood and get the same results? Is it that simple to not have to worry about wood rot?

Have you priced that material compared to wood?

If you keep you boat made with wood covered and dry when not in use it will last as long as a composite built boat.

 

[kjsAZ]

Wood with fiberglass around is a composite construction........ Just saying

13 years ago I build a hovercraft from 1/2" structural PU foam with fiberglass skins (Epoxy). The 15.5'x7' hull was that lightweight that the admiral and I could lift it from the floor onto saw horses without any issue. Yet it wasn't flexing at all.
Sold it because you couldn't get insurance for hovercrafts in the US.

 

[anamealreadyinuse]

Can you switch out the H60 Divinycell or Corcell with the same thickness as you would marine grade plywood and get the same results? Is it that simple to not have to worry about wood rot?

 

[kjsAZ]

No it's not. All these products have a much lower shear strength than wood. What happens under flex is that the core will break and separate and then it's gone. The entire construction has to be different taking that into account.

If you want it to last longer than 30 years use Epoxy instead of Polyester. Vapor penetration in Epoxy is factors lower than in Polyester. Soak the dry wood with thinned Epoxy and then encapsulate it well. Will last forever.

 

[anamealreadyinuse]

Got it, thanks as always...love this forum!

 

[jigngrub]

Thinning epoxy just weakens it, like watering down beer or whiskey.

 

[kjsAZ]

Thinning epoxy just weakens it, like watering down beer or whiskey.

Yes, but for penetrating wood for water resistance it works fine. the strength comes from the fiberglass around the wood.
The Epoxy itself isn't weaker after curing there's just less Epoxy and thus it is weaker. You only thin it with 5% MEK max and use the lowest viscosity resin you can find.

 

[Woodonglass]

This ^^^ is not actually correct. The molecular structure of the Epoxy resin is actually "messed" with by the action of the chemicals used to thin it and does affect it's waterproofing properties as well as it's strength and elasticity properties. It pretty much messes up the whole molecular structure of the resin. We have one of the leading expoxy resin experts here on the forum and I've learned a LOT from him. He teaches seminars all over the nation about all kinds of resin and their properties. He's called to tesitify when things fail etc.. He's quite adamant about not thining epoxy for any reason. Encapsulation is what waterproofs and seals the wood, not penetration.