I been collecting some hardwood to make some paddles. I bought a 12ft scaffolding plank for 99p on eBay.
To make a paddle draw the paddles on the plank and cut it out with a jigsaw. If the plank is 4" thick cut it in half. Take the shaped paddle outline and use a sanding disk to shape it from a T shaped handle to a nice broad flat rounded paddle. Use the sander to thin the paddle blank with it tapering to the tip of the paddle end. make sure that the handle and top third of the paddle are quite thick, almost the thickness of the blan k and the paddle can taper from the blank thickness to about a third of the thickness.