Boat Building Forum

Find advice on all aspects of building your own kayak, canoe or any lightweight boats

Re: Strip: Debating over hull glass

My planned use is mostly calm water inland lakes and rivers and possibly the Great Lakes in good weather. My gut tells me 4oz with wear strips on the keel should be fine, but I'm *far* from an expert.

I started building using 6 oz. E-glass, the common fiberglass cloth used in the 1980s. I used Dave Hazen’s Book on stripper canoes as a primary source, as it was given to me, along with my initial inspiration for stripper canoe building by my friend Norm Sims (co-author of the wonderful book about canoes, “CANOES, a Natural History in North America”).

I started building stripper canoes because I wanted a lightweight canoe for the wilderness trips I was doing at the time where there were many portages. So building a lightweight canoe was my number one priority. Therefore, I started using 3/16” thick strips to reduce weight and have never looked back.

Initially I used 6 oz. glass inside and out with a second layer below the waterline. This was pretty bulletproof. But I wanted to reduce weight so I went to one layer inside and out. I tried 4 oz. E-glass but I found it was not rigid enough to resist denting and this was on the decks of kayaks. Then I heard about 4 oz. S-glass fiberglass cloth (available from Sweet Composites) which is 40% stronger than 4 oz. E-glass. So I’ve been using one layer inside and out of 4 oz. S-glass for about the last 15 years and I’ve been happy with the lightweight and toughness of this lay-up. The only difference with this has been to orient my interior glass at 45˚ to the strip joints as suggested by a West Systems study which said this would increase tension strenght.

Fiberglass cloth is good at impact resistance and not good at abrasion resistance. Additional layers of glass, applied on stem/keel edges are a waste for time IMO. I use a special abrasion rsistant cloth like polyester, (Sweet Composites) Zynole, or Dynel (Defender Industries). These cloths come as 60” wide pieces. I cut a 1” wide piece x 60” and epoxy to the stem edge just above the waterline running toward the hull center on the keel line. One layer lasts a very long time. I paddle in rocky Maine and Georgian Bay with unloaded and heavily loaded kayaks so I know it works.

Live Long and Paddle,
Rob Macks