My homemade pedal powered boat had been close to perfect but I couldn’t pedal quickly enough. This was barely making me breathe but stressing the leg muscles so I knew it would be difficult to cover longer distances on the canal where I sail. I added a chain and sprockets to double the pedalling speed but have had a number of technical difficulties . I allowed the chain to be slack, guiding it onto the sprockets with fabricated chain guides and after 3 tests of different versions I still had an annoying clicking from the chain. The only solution seemed to be to add a mountain bike rear mech. as a chain tensioner and fortunately I had one in a drawer in the garage. I think it was some time last year when I went over the handlebars on a steep descent and twanged the mech. It still worked but wouldn’t change gear crisply because it was slightly bent and no amount of tweeking made it any better. In this new application it wouldn’t need to shift gear but merely keep tension on the chain to take up the slack so I modified it, added a bracket and welded this on to the boat’s structure.
I took the boat down to the canal and was delighted to find that the chain now worked perfectly. The boat isn’t any faster but by doubling the speed at which the pedals rotate it’s now more aerobic but easier on the legs. I pedalled for 53 minutes and according to the app. Strava I covered 3.15 miles. I tried some faster pedalling but still could only reach a little over 60 rpm which, whilst slow compared to cycling, is much better than the 30 rpm I could manage before I added the chain. I like being on the water and get a lot of attention from passers by. Today I got a good workout and could feel the effect in my calves and quadriceps so now know the exercise is much closer to cycling than it was previously. It’s enjoyable enough to not have to be described as type 2 fun. The big difference between pedal boating and mountain biking, as a workout, is that I can choose how hard to turn the pedals at any time in the boat whereas on the MTB the gradient plays an important role.
It seems I’ve achieved all the objectives I had when I decided to build a boat. It floats, it doesn’t leak, it’s stable, steers well and goes along at an acceptable speed. All I need to do now is tidy up the paintwork, improve the cowling of the paddlewheel because it splashes some water into the hull and enjoy sailing.