:Like everyone, I want to maximize strength-to-weight
: m

Hi M

An ultra light boat is very nice when you are lifting it onto the roofrack. The greatest stresses on any boat are actually when it is on a car or ashore with someone in it checking footrests etc., and not supported all over by the water it is displacing. Once the boat is on the water a couple of extra lbs here and there are not really noticible. On some designs a little extra weight actually improves the boat's behaviour. I know someone who puts a lump of lead behind his seat in an old NordCap because it is designed to carry expidition weight and is more stable loaded. A lot of extra weight will affect your acceleration to crusing speed, but once there inertia does its job and holds you at pace. For this to be apparent you would be talking about LOTS of added weight.

I think that minimising weight is best achieved (when using standard materials) where the application of epoxy is concerned. Epoxy is very heavy, (a kilo for every litre). By saturating the first coat well in a well heated space and then squeeging out all excess resin (do not try to fill weave with the first coat) you will adhere the glass to the wood as closely as possible. Glass floats on resin and if you keep adding epoxy you will be thickening the epoxy layer between the wood and the glass. This only adds weight, not strength. Pull your glass tight (no wrinkles) and then overacot with only enough epoxy to fill the weave. Every unnecessary coat adds weight, but no strength. This is especially imporrtant inside the hull and under the deck where you do not need to overfill the weave as you do not need to sand. also resin pools more easily inside and it is tempting to let it, as squeezing it out messes up your glassing job. I am very stingy when applying resin to the interior. If perfect transparent wetout is not achieved no one can see it anyway.

Expensive UV varnishes require fewer coats too.

Etienne
South Kerry
Ireland