I believe Sam's experiment indicated that if the experiment was the proper experiment to do that 8-18oz of total glass over 1/4" wood provided the same strength as wood alone.

I believe that another who's name I have been asked to not post here indicated that the wrong amount of glass can reduce the strength of wood (as you suggest).

As to why you need glass and wood. You neither, either, or both. If you do the engineering correct, you can make a good paddle out of many combinations of many materials. (glass/epoxy may provide waterproofness for a wood paddle; wood may provide a mandrel for building a glass/epoxy paddle)

A paddle which is cracked CAN NOT be fixed well enough to trust.

I ran across a fellow on Lake superior who is building 18oz paddles and some nice boats. He asked me to say hi.

: As I remember, Sam Mcfadden's experiment has proved that encasting wood in
: fiberglass does not increase the utimate breaking strength, but rather
: lower it.
: The theory is once a minor break starts, the localized stress is unable to
: redistribute to other area, thereby, concentrated in one single spot.
: Result in the utimate failure of the entire unit. If component (either
: wood or fiberglass) is designed to be able to handle the stess single
: handly by overbuilding, then, why do we need the other?
: Sam, what is your opinion?