Rice Lake Skiff - layup interior - two layers of glass

[Alan]

I am at the stage of fibreglassing the inside of my Rice Lake Skiff, but I'm having some difficulty laying out the cloth. The instructions call for two layers of cloth 60 inches wide that is meant to be trimmed at the water line on both sides. This results in a football shaped overlap of the two layers of glass.
However, I have been in touch with another builder who appears to have butted his layers of cloth along the centre line and draped the excess on both sides outside of the hull and trimmed to the top of the planks - thus having no overlap inside the hull.
As I've already overlapped on the outside of the hull and there was a slight raised line along the overlap which I tried to diminish as much as possible - but it remained visible, I'm wondering whether the butting at the centreline is the way to go. I suspect the strength of the hull will be adequate with two layers outside and one inside - especially since my canoes with only one layer outside and inside withstand plenty of abuse.
Thanks for any suggestions or tips.
Alan

[Moonman]

Depending on your strip thickness, the hull MAY be strong enough without the overlap but you will be negating the added strength of the second layer of glass on the outside. The glass needs to have the same layer thickness on each side of the wood layer to maintain its maximum strength. In effect, you would be adding weight/expense of the second layer outside and not getting the strength benefit it could confer, albeit you would get increased abrasion resistance.

Personally, I would overlap. You could sand down the ridge over say a 2" span and get a nice even transition that would be hard to see or feel.

Final choice is yours. Whatever you do, don't fret too much. You built it you can fix it if need be. You can always go back and add another layer afterwards if you feel its warranted.

Moonman.

[Patricks Dad]

I would agree with Moonman. Overlapping the cloth from each side creating a 2X thick football will produce the stronger result (and matching the outside lay-up). Feathering the epoxy on the seam should allow for a smooth transition that won't be noticeable. I saw a trick a couple years ago using masking tape to allow the edge to be cut neatly after the glassing is done which allows you to precisely follow a strip edge with the glass (I couldn't find with a quick search but perhaps you are familiar with it - I'll look again when I have more time).

thanks

[Glen Smith]

Extra glass on the exterior increases abrasion resistance. Extra glass on the interior increases impact resistance. It is like when a bullet makes a much larger hole on the exit side that on the entrance side. Hitting a rock with force causes more visible damage on the interior than the exterior.
Careful scraping and sanding has always produced invisible seams for me.

[Alan]

Thank-you gentlemen - great replies. And Moonman: I had never heard of Vandorf before although I have numerous relatives in Aurora and have spent many days visiting my cousins and their families there.
I'm on my way to the garage with my better half and we will try to lay the cloth out in an overlap - if that becomes too frustrating, we will use the fallback to the centreline.
Alan