: What is the most structural fiber orientation?

Consider the traditional Adirondack Guideboat. They were built with 1/4" thick cedar planks over 1/2" ribs spaced every 4, 5, or more inches. Obviously, no fiberglass involved. The longitudinal strength of the cedar was found to be sufficient for a 17' boat to carry three people plus gear. The only transverse reinforcement was the widely spaced ribs.

In a modern strip-built boat, the fiberglass fullfill the function of the ribs. By that logic, it would make sense to experiment with unidirectional cloth oriented at 90 degrees to the wood grain.

Using standard woven cloth, orienting the fibers at 45 degrees would probably make sense, but there are practical reasons to orient it at the standard 0/90°. It is easier to roll the cloth down the length of the boat then trying to lay diagonal pieces.