So this turned out to be a much better test than I thought it would be. Thanks to the good folks at Allen’s Trout Farm, we are able to test the new boat in one of their trout ponds that doesn’t freeze over because the water is constantly circulated. Because this pond was quite long, I was actually able to get some speed going to do a very crude speed/watts test.
Results:
1. FABRICATION STRENGTH: My seat cracked at one of the seat post joins – no biggie, as I was going to reinforce those joints anyhow
2. DRAFT: I was wearing 6 pounds of additional clothing (hip waders, etc), the boat weighs 27 lbs, and I’m about 155 lbs right now. We measured the draft at 110 mm which was exactly on target. However, it seems that my floats are too deep – I’m guessing they could be raised by 1/2″ – however, I designed them to be adjusted lower by inserting spacers. I’ll either have to raise them by cutting a chunk out of the tubes, or, assume that my “race configuration” (150 lb me, – 6 lbs for winter clothes) will mean the boat could sit 1/2 higher in the summer… ?
3. PROP: My model aircraft prop is fastened to the spring steel shaft with a self-tightening nut, but by my 4th pass, the prop started slipping on the shaft, and the nut was almost off the threads. So, I’m going to have to do something better to secure that prop onto the shaft. A pin, or maybe I’ll just epoxy it on.
4. SPEED: I could only put the LEFT PowerTap PowerPedal on because the right pedal requires removal of the large chain ring to access the allen key pedal bolt.. so, I went with measuring power on one side only which is good enough. The lake was not very long, so I wasn’t able to get up to “cruising” speed, but I did measure about 9.8 km/hr at around 110 watts @ a cadence of 72. Now that’s way slower than it should be ( I should be at around 11.5 to 12 kph at 110 watts), but I was still accelerating by the time I reached the end of the pond, so it’s not a fair test. Plus the water temp was probably lower than zero (air temp was -5 C).
CONCLUSION: So I’m still unsure about the speed… The cadence of 70 to 80 felt normal, but compared to my nocom / mag trainer, the effort felt way too light to really be 100 watts (it felt more like 50 watts). I know the mag trainer feels harder that an outside ride due to a lack of momentum – and perhaps the same here. If this really was 100 watts, then I’d guess that 150 watts would be a more realistic all-day target. But if that was the case, then I’ll need to change the cog to a smaller gear to decrease the resulting cadence required to get to 150 watts (or get a courser pitched prop). I won’t really know until I get a chance to put in a long day on a big lake and measure my average watts and resulting speed. The water temp, and short accelerating distance could also have been factors.
