After my first test of my newly built boat I was pleased with its stability on the water. I tried a pedal to paddle propulsion system but wasn’t getting much power into the water, meaning that it was very slow. I decided that it looked impossible to develope this propulsion system so chose to build a paddlewheel. This had worked successfully on my first boat but it has taken me around 5 weeks to get it ready for a further test.
I pulled the boat down to the canal and bolted the 2 halves together. I started early because it was due to be hot later on. I put the boat on the canal and climbed aboard. It feels very safe and doesn’t move around once you’re sat down. I pedalled away to once more find that I could spin the pedals frantically, feeling little resistance from the water. The paddlewheel is moving a very similar paddle area through the water, at a slightly higher speed, so why doesn’t it perform like my dinghy?
I think that the difference between the previous dinghy and the current catamaran in terms of propulsion is due to a simple reason. The dinghy had a flat transom (rear of the hull) which it dragged through the water. This flat area would have pulled water along behind the boat so it was as if the paddlewheel was acting on virtually still water. This time there is no such effect occurring so it seems that I need to gear the paddlewheel up significantly, which is not too difficult.
in my disappointment I didn’t even take any photos of the boat. The picture at the top is my trace from the app. Strava which shows that my average speed was 1.9 mph. The dinghy would have probably averaged around 2.5 mph on this short sail, so I’m not too far away. My next step is to use a much bigger sprocket at the pedal end of things. This will hopefully give a much greater resistance to turning the pedals and spin the paddlewheel much quicker. I also need to add a splash guard to keep me drier. The work is limited and I should be back to testing in a few days.
Mountainbiker 