Quote:
Originally Posted by JBASS02
. . . The mi/gal numbers are rough... +/- .0001 not sure who set that as the default significant figure?
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Yea, neither the MPH or GPH number are accurate to more than
+ 0.1 so any more than 1 decimal place is just looking at noise in the signal! What really counts at the end of the day is the overall average. My experience with the I-Command gage that provides instantaneous mpg is that the optimum speed for the 20’ hull is somewhere in the 22-25 mph range, which seems to be what your data shows and is about where it reaches minimum running angle.
The 1969 Boating Magazine test of the 20’ Seafari in the Literature section showed runnning angle decreased until speed reached 25 mph and then stayed constant until it reached ~ 35 mph. At that point it began to increase. I believe that’s because there is a slight wedge built into the aft 10’ or so of the outer panel, but that panel is completely out of the water at about 35 mph, which would eliminate the “trim tab” effect. If you lay a straight edge on the keel at the transom, it looks like there is a bit of rocker built into the inner panel, which would allow the bow to rise once most of the lift is coming from the center panel. That would allow the bow to rise and reduce wetted surface and increase top speed . . . Just one of many subtle but brilliant details that Moesly built into his designs that allowed his boats to dominate their classes in the Offshore Power Boat races!