Epoxy (such as West) is the best to use for over wood.....but you can also use polyester resin if you are dry storing the boat......the epoxy resin provides a much better seal for wood. I would never leave a polyester resin fiberglassed boat in the water and would limit exposure to elements if you want it to last a long time.
Another great product out is Gluvit....but it is also at least $75 per gallon....but I will say this, there is absolutely nothing better for sealing (especially aluminum, because Gluvit expands with the hull).
Making a boat the right way and the best way is not a budget concious person's way to save money. Do it right with the best materials and you will be awarded over time and with piece of mind in a quality product, a safe product and a functional product.