The video below shows all the things you need to know to make a low-tech outboard motor in a couple of hours once you have obtained the materials. This project uses parts that you can buy in the local hardware store and the marine supply store. The propeller and 90° drillhead you can also find on the internet.
Wooden Outboard Motor Powered by a Cordless Drill
This project shows a simple design for a trolling motor made from wood and a few other parts.