Prop: 15.25x15
Weather: Windy and somewhat lumpy seas. I was able to find some calmer water, but some of the runs were done downwind, some upwind. A calm day and two way runs will be required to get better numbers.
Engine: Still some tweaking to do here as well. The recommended RPM range is 5500-5800.
Knots MPH Gal./Hr RPM MPG Theo Speed Slip
2.8 3.22 0.5 630 6.44 4.66 30.9%
4.3 4.95 0.8 1000 6.19 7.40 33.1%
6.0 6.90 1.3 1500 5.31 11.10 37.8%
8.0 9.21 2.1 2000 4.38 14.80 37.8%
12.3 14.15 2.8 2500 5.06 18.50 23.5%
16.5 18.99 3.8 3000 5.00 22.19 14.4%
21.0 24.17 5.0 3500 4.83 25.89 6.7%
23.1 26.58 7.1 4000 3.74 29.59 10.2%
27.3 31.42 8.6 4500 3.65 33.29 5.6%
30.0 34.52 11.1 5000 3.11 36.99 6.7%
33.5 38.55 14.5 5600 2.66 41.43 6.9%
So it looks like the sweet spot is somewhere around 3500RPM right now. We'll see if those numbers can improve. I'd be thrilled to get 5MPG!