Dick Barnes on Ice Dancer, a Nordhavn 50, has done rather exhaustive documention of the fuel economy his boat gets at 1000 RPM intervals. The results are significantly better fuel economy than what Bluewater has been experiencing. If Georgs asks, Dick may be willing to share his findings. While I have not documented my fuel economy on Flat Earth, also a Nordhavn 50, the way Dick Barnes has, my fuel economy has been right in line with his results. Thanks Dick. My economy has been very close to the 3 gal per hour at 7 KTS listed for the Krogen 48. The specs for the N50 are: Cp .65 D/L 286 displacement 80,000 LBS The specs for the N47 are: Cp .57 D/L 298 displacement 85,000 LBS Obviously, the designed specifications of the two boats are very similar, so why would the fuel economy be different? Are there other N47 owners out there, such as Scott Strickland, who have better fuel economy than Bluewater? One last variable to throw into the mix is the differences between the engines on the N50 compared to the N47. While both boats have Lugger engines, the N50 produces 300 HP and cruises at a lower RPM with more reserve power. The N47 which has 173 HP and cruises as a higher RPM. I'm not sure how the difference in engine sizes works into the equation. I always thought that smaller would be more efficient, which brings us back to the question: What are other N47 owners getting for fuel economy? Phil Eslinger