Help with Honda BF 20 HP prop on 16ft wooden dory

[spottydog]

Re: Help with Honda BF 20 HP prop on 16ft wooden dory

It surely is better, I bet it feels peppier.
I guess you could make a 2 way run and average it , or would you run across the tide?
Or perhaps drift in the tide to get its speed.
The site I use says 38 km is 23.61 mph, assuming the same 8% slip as the 10" indicates rpm is 6231.
With the increased rpm the slip might be lower which would lower the prop calulator rpm.
It would appear that a 9" 3 blade will further increase the rpm.
Is it a Honda Tach?
I assume the max rpm for the 20 is 6,000.

Tacho is TELEFLEX LIDO 7000 RPM W/ hour meter. I have it set to 6pulses which is what is should be for the motor. No doubt there.

Max for 20 is 6000rpm. I read somewhere 20hp is developed at 5500rpm, but that was just someone else s post. Specs cay it should run between 5000-6000rpm, so I am now within that not just on the lower limit.

Will have to wait a week maybe before i test the 3 blade.

I will also be checking the tacho out with the handheld tacho at the flywheel at some point.