How to Make Boat Floorboards
- 1). Choose the right kind of wood for the floorboards. If you're decking will be covered with a sheet of vinyl, sheets of marine plywood provide better support than individual planks. If your final decking is individual planks, match wood of the the surrounding decking as closely as possible. Measure the area where the boards are to be replaced with a measuring tape, twice: the carpenter's adage of "Measure twice, cut once," should be adhered to, to avoid problems with size.
- 2). Cut the floorboards to the required size and shape with a jigsaw or circular saw. If you're replacing floorboards, correct measurements are doubly important, since the new floorboards will have to fit into a space of a size that's already established.
- 3). Sand the floorboards before sealing their surfaces. This process is best done by hand, since the sanding should follow the grain of the wood. An orbital sander may seem like a short cut, but an orbital sander raises the grain of the wood and opens a pathway for water that even the best sealants have a hard time closing. Sanding by hand, with sand paper does not do this.
- 4). Prepare the floorboards for installation by painting or otherwise sealing all surfaces of the boards, even if the floorboards are marine plywood, unsealed edges will admit water that, eventually, will break down the glue that holds the plies together. Seal the sides of the boards and their ends as well as the top and bottom surface, since these are areas where the grain is more exposed than on the top and bottom.
- 5). Install the floorboards by the least damaging means possible and caulk the joints between the floorboards and walls, and between floorboards and floorboards. "The least damaging means" might be a finishing nail or a small screw, or steel angle irons that are bolted or welded to the deck to form a framework to hold the individual planks tightly together. For sheets of marine plywood, screws or other fasteners will be used to hold the sheets to the supporting frames.
There are a number of products, from marine silicone caulk to oakum--a twisted rope, saturated with tar--that serve well to caulk a boat's floorboards. The type of product used isn't as much an issue as is a carefully done job that keeps water from penetrating seams and joints.
Source...