Fiberglass is nasty, nasty stuff - and very unforgiving. I find that its' best used to put over the top of an existing structure, because it is very difficult to get the layering down on a mold - especially if you're doing it by hand. They have big and expensive commercial machines for putting it into molds and injecting it with resin. If you're patching an existing piece of work, or putting a couple of layers over wood to provide some extra strength, that's one thing. Creating an entire structural piece of fiberglass is quite another thing, and it requires some real know-how and equipment. I know some boat-builders who started out wrong & quickly developed allergic reactions to the chemicals - ending their boat-building careers prematurely. After that, they switch over to wood or do something else.