Weight savings with glass ...

I built the balsa canoe because I knew and had helped with some other boats made in this method. The part I was playing with was too see how far down I could go.

One of the big advantages at the time was that it reduced the amount of epoxy absorbed by the core - and much less than end grain balsa. Timber strip absorbs much less resin than foam - I think the difference for the wide bodied skiff moth of the time was around 5lbs or around 15% of hull weight. So when you do the glassing it absorbs a lot less. It was this property that prompted the development of the "Duracore" product developed by the Australian WEST agent, Arnie Duckworth, relevant to larger boats.

The secondary area of weight saving is the weight of resin needed for the cloth.

In general you need a bit more than 2oz of epoxy for 2oz glass, or a bit more than 6oz of epoxy for 6oz glass and so on.

This should make the weight savings a bit more calculable.

One additional piece of information is that because of the high price and limited availability of Cedar in Australia we are now looking at using Paulownia - a chinese timber that is a bit cheaper and a bit lighter. Not as light as balsa though - and it seems to be as dent resistant as the Cedar by the time it is glassed.

I have attached a picture of a paulownia canoe that was built at the recent Duck Flat Spring School.

Photos are interspersed in this set
http://www.flickr.com/photos/boatmik/sets/72157602281214723/

Best wishes
Michael Storer