fiberglass brittleness

[brianlex]

About 10 days ago I finshed fiberglassing and epoxy filling a strip canoe. I used Raka epoxy and 6 oz. cloth (2 layers on the outside and one on the inside). When I was sanding the boat on my lawn I rolled the boat over & heard a faint crack sound. I was surprised to se a 4 inch crack in the bottom of the canoe revealing the fibers of the cloth that just prior were invisable. It is visable on both sides. After investigating I found a surface root from a nearby tree was the culprit. The boat did'nt seem to roll over that hard to me. Any ideas? The canoe is 16' and I used 3 gallons of epoxy.

[Ric@Noahs]

I have never used Raka Epoxy, but I don?t think it would be brittle enough to cause a crack with a minor bump. One thing that could cause the problem is a gap in the cedar that was not filled with resin when you fiberglassed the boat. Another possibility is a resin rich layup. Three gallons is a lot of Epoxy, even for 2 layers of glass.