Commencement Bay Race 2012

I finished the side drive system yesterday and took it out for a spin at the Commencement Bay Race today. Just as I started pedaling I heard a clunk-clunk-clunk which I determined to be the right crank arm hitting the head of a bolt that was being used to prevent the chain from being too sloppy. It was kind of strange to me that it was happening as it didn't seem to be hitting when I tested it in my garage with me pedaling. Sigh...apparently the crank mount I put together flexes just a little too much, causing the interference. Anyway, it wasn't so bad that I couldn't pedal reasonably efficiently, so I decided to race after doing a couple of turns near the starting line and getting the feel of things with the new drive and dipping rudders.

I found the ratio was a bit too high for my liking. Even at cruising speed of roughly 7 to 7.5 mph my cadence was around 60 rpm. It could have been a little higher, but I was too busy keeping up with the other racers and taking photos at the time. The offset thrust was also quite noticeable in its affect on the direction of travel. The boat has a strong tendency to turn to port, regardless of my leaning to one side or the other. The conditions were flat, with very little wind. The propeller shaft was vibrating a little, but otherwise appearing to work well. The clunk-clunk was a nuisance, but as I said it didn't seem to be impeding my pedaling. The relatively slow cadence was counterproductive to attempts to try sprinting, so I stopped for a moment and switched to a somewhat smaller chainring that was on the crankset to see if I could use it to get my cadence faster. Unfortunately, the chain was far too sloppy and derailed. So, it was back to the large chainring. About 16 minutes into the race, and about 23 minutes after starting from shore one of the shear pins in the Mitrpak R-082 gearbox broke with a big CLUNK.

I drifted for the remainder of the race, taking photos of the racers as they passed by. The currents in the bay moved me at about .5 to 1 mph, depending on where I was, sometimes turning the boat around as I hit eddies caused by a distant river entering the bay, being countered by the tides and very light breezes. Eventually the chase boat arrived and towed me back to the start.

I am a bit disappointed in the performance of the gearbox. I was under the impression that it should have handled the loads presented for a much, much longer period of time. I'm planning on returning it to Mitrpak to have it examined and repaired, and possibly replace it with a R-081 though the rating is not much higher. The R-061 used in the Cadence has a much lower specification, so I am not sure why the R-082 failed. Both gearboxes are supposed to be configured to have solid than rather than roll pins as they were special ordered to have them.

Lastly, I tried inserting a sheet of Coroplast between the closed cell foam and the open cell foam layers in the seat pad. As the pedaling portion of the race was cut short I can't say if there is much of an improvement, but I think it was working better than without the Coroplast layer in distributing the load.