An amateur boat builder has very few choices of materials for boat building. It is quite possible to build fibreglass boats and canoes but a mold, to build the fibreglass hull on, is needed. Cost of this mold is unfortunately quite high. Unless you want to build several boats from the mold it is really not an economical way to go. Building an aluminum boat or canoe is also possible but this needs considerable skill in sheet metal work which not too many amateurs have. The final alternative is to build a wood or plywood boat. Plywood boat building is the way that most amateur builders go. Plywood is quite inexpensive and is easy to work with. Small dinghies can be built from just one sheet of plywood to make a boat around 8 feet in length or a bit less. Plywood suitable for building boats can be either marine grade (which is best but costs more) or ordinary exterior grade. Interior grade or utility grade cannot be used. These grades of plywood are not made to withstand exposure to water and will delaminate since the glue between layers is not waterproof. Many boat plans require plywood lengths which are greater than the standard eight foot sheets available in building supply stores. Marine plywood in lengths of more than than eight feet is obtainable but may need be specially ordered. If plywood in the required length is not available, the simple solution is to join two sheets together by using a butt joint. Simply lay out the complete length of the boat part on two lengths of plywood, layed end to end, and butt joint the ends of the part together. A butt joint is made by laying the two ends together and laying another piece of plywood about a foot long over the joint. Then glue this foot long piece in place with marine glue or epoxy glue. Next use several wood screws on each side of the joint (from the inside where the short piece of plywood is placed) to make a very strong joint. The butt jointed section will actually be stronger than the rest of the length if you do it in this manner. Do not use a scarf joint in which the two sections are tapered and glued together. The butt joint is much stronger and is standard practice in boat building. The short piece of plywood for the butt joint should always be inside the boat. If you butt joint both the sides and bottom of the boat you should arrange the joints so that they are staggered and not at the same spot. Do not let the minor problem of getting longer than standard plywood stop you from building a boat. Butt jointed plywood parts are as strong as or stronger than single lengths, and many boats are built this way. You will find a number of good plans for plywood boats of all sizes in my eBay store: http://stores.shop.ebay.com/Books-Plans-and-Prints-4U__W0QQ_armrsZ1