Benefits to glassing the underside of the deck


I am builiding a Wood Duck 12, first build. What are the benefits to glassing in the whole interior of the hull and underside of the deck? The directions call for glassing in the jsut cockpit and none of underside of the deck. 

If I do this can I (should I) use microballons to make it lighter? 

 Thanks for the help,


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RE: Benefits to glassing the underside of the deck

Hi Brian,

I am sure that if you build the Wood Duck as the plans state it will be fine; other builders who have done that can confirm this.  

I built a Shearwater 14 last winter and chose to apply fiberglass and epoxy to the entire interior of the hull and deck (not just the cockpit areas).  I did this because it (theoretically at least) provides greater strength and interior abrasion resistance.  It also increases the weight a bit since you need more epoxy to saturate the glass.  It becomes a trade-off of weight versus how much strength do you really need.  Obviously for normal use, the extra fiberglass is not needed; it's a personal choice.

Using microballons in the end pours would make them lighter, but I'm not sure how you were thinking of using them under the deck (they are a filler to bulk up epoxy by decreasing weight when epoxy is used for filling voids).  

Hope this helps,


RE: Benefits to glassing the underside of the deck

I completely glassed the inside of my WD12. My reasons for doing this were the same as Kathy's for her Shearwater - increased strength and abrasion resistance - as well as a better encapsulation of the interior to prevent water damage caused by hosing out the inside.

The abrasion resistance is obvious. The increased strength come from the fact that completely glassing the inside turns the boat into 100% composite construction with the wood acting as a core material. It's now a wood between glass sandwich. The glass resists forces in tension, the wood resists forces in compression and together they are stronger than either would be individually. This makes the boat stiffer and better able to resist punctures than if there was no interior glass.

The downsides to this were that I had to buy extra glass and epoxy, the build took longer and the boat ended up heavier than if I hadn't done it. But in my case I could afford the cost, didn't mind the extra time and the final weight was 39 lbs (1 lb below the weight specified in the CLC catalogue). So it was worth it to me.

Again as Kathy points out, it's not necessary for a successful build. The CLC demo boats do not have the interior glass and they have survived years of use and abuse by thousands of paddlers (including me) at dozens (at least) of demos, as well as being dragged back and forth across the continent to get to those demos.

On my build, I did not fill the interior weave at all (to save weight and to reduce the amount of work).





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