Seats can also be customized and padded using neoprene, either the wetsuit or kneepad type, depending on the wishes of the user. I recently came across a web page with detailed instructions for customizing the seat and entire outfitting in a sea kayak. There are a lot of tips there that can be adapted to other similar jobs as well. Kneepads and other outfitting can be done with neoprene or Minicel as desired. Minicel is softer but it is somewhat slippery when wet.
Neoprene provides better traction under one's knees and is more durable.
To glue wetsuit neoprene in this manner, it is best to scratch up the skin side with coarse sandpaper, just enough to make small tears in the skin, then wipe the dust and any other residue off with acetone or lacquer thinner. Glue the cleaned surface to the Minicel or fiberglass surface with contact cement or neoprene glue. With any contact cement, coat both surfaces to be joined, allow to dry tack free, and then press together. If one must glue down the nylon side of wetsuit neoprene, coat once with cement and allow to dry, then coat and dry again before pressing the parts together. Another use for Minicel is to make blocks for supporting an open canoe on a car top without the use of racks.