You need to put this in the context of how you intend to use the boat. Yes
the hull will be less strong with only the outside glassed, but it doesn't
mean it going to fall apart on you. I have a stitch and glue canoe that has
no glass except for 2 inch tape on the seams. My friend has the same boat
built the same way. We use the boats hard but don't abuse them, they have
never given us any cause to be concerned, granted it's only flat water
paddling. We have been in some situations that should have caused major
damage to the boat but nothing happened.
I guess what I'm trying to say is that if you foresee rough use of your
boat, then ease your mind and glass inside and out.

Bill

wrote in message
oups.com...
Looking for experienced boat builders here. I am building an okume kit
kayak and am wondering if I can save weight by not placing a full glass
layer inside the hull.

My thinking is that I can get away with only glassing the butt joints
and edges on the inside along with a thin coat of resin for
waterproofing. Yes its going to be weaker (no fiberglass to take the
compressive forces) but has anyone done any tests to see how much
weaker?

If I have to I might just glass the cockpit area to help with required
durability (feet, stones and sand). Will this create any weird foces
beyond the bulkheads? (My boat will be 17 feet long).

Links to experiments on this would be great!

Thanks
Gary