Guys,
I just got my 4 blade propeller in the mail this morning, so we took it out and it did great, It's a "COMPROP" brand and is made from a magical composite of Kryptonite and Unicron hooves, I think.
My question is: I took GPS speed readings at a few RPM close to WOT, and the slip is between 2.5% and 3% for all three readings (using some of these online calculators). That seems very low to me - not that I'm complaining. Just wondering if that slip seems impossibly low to any of y'all? Should that give me better fuel economy? What is "good" fuel economy for a boat like mine?
Raw data:
1978 115 Evinrude. WOT should be and is 5000 RPM. Prop is 13" pitch, 4 blade 13.5" Diameter. Top Speed at WOT was 30.0 mph (GPS). Boat is a Parker 18 center console.
Side note: It comes out of the water nicely, but I didn't try it with a skier. I'm still working on cavitation/ventilation when I turn sharply. Any suggestions? The motor is as low as I can get it (20" shaft).
I just got my 4 blade propeller in the mail this morning, so we took it out and it did great, It's a "COMPROP" brand and is made from a magical composite of Kryptonite and Unicron hooves, I think.
My question is: I took GPS speed readings at a few RPM close to WOT, and the slip is between 2.5% and 3% for all three readings (using some of these online calculators). That seems very low to me - not that I'm complaining. Just wondering if that slip seems impossibly low to any of y'all? Should that give me better fuel economy? What is "good" fuel economy for a boat like mine?
Raw data:
1978 115 Evinrude. WOT should be and is 5000 RPM. Prop is 13" pitch, 4 blade 13.5" Diameter. Top Speed at WOT was 30.0 mph (GPS). Boat is a Parker 18 center console.
Side note: It comes out of the water nicely, but I didn't try it with a skier. I'm still working on cavitation/ventilation when I turn sharply. Any suggestions? The motor is as low as I can get it (20" shaft).