: Rehd
: I have a great reluctance to put myself into a boat that has not been
: constructed using methods that have passed the test of time. I am not
: saying that I am not interested in progress and innovation. Progress and
: innovation should be well thought out with the idea of making a superior
: product. For instance, I will only use Lloyd's approved marine plywood in
: my plywood boats, I will never go out onto the water in a boat that has a
: hull that may break because of wood or glue voids. I will only use
: waterproof glue. I will always make a test scarf joint and bend it to
: failure to test the wood, the glue and my skill.

: Think of how much wood there is in a kayak and how much you discard from a
: 8:1 scarf. How much less wood will you buy if you make 2:1 scarfs. When
: you look at the amount of wood that you need to build a boat, you probably
: aren't spending any more money. The price building a boat of the top
: quality wood is not that much more than unknown quality wood.

: Water is unforgiving. When I go out onto it I bet my life on my skills and my
: equipment. I will not give my life the same value as a few feet of wood.

: Forgive me if I am preaching, I just don't anyone to get hurt.

: Pete Strand

I totally respect your views, and I concur.

But, scharf joints have been used for many years on Home Built aircraft and have undergone many more times the tests and stresses that any kayak could ever go through. I know of two personally that used skin of 1/8" aircraft spruce scharfed with an 8 to 1 or 12 to 1 ratio, and both have flown in several flyins across country. There are many different aircraft from sport to stunt that use these joints. In most cases, these joints are much stronger than the actual wood they are constructed from. In tests useing Titebond and Resorsinal glues, these joints have been broken, but it was the wood that failed around the joint, and not the joint. I can't quote you any scientific studies, or anything professional, but, I have seen this done at EAA meetings by the members themselves. My father participated in one where two 2 x 4's were end glued and when set, put on two saw horses about 12' to 14' apart and one member stood on the joint. When he jumped up and down on the joint, it broke and was shown that the wood shattered and not the joint. This was done with a yellow glue. I would trust these joint. However, you can't trust just anyones joint. They have to be made right, and have full contact over the entire surface area, or they suffer in strength. Same as any glued joint that I know of.

Rehd