We do not have a fuel gauge on Lealea so I keep meticulous records of engine hours and fuel added. Over time I have determined that our Yanmar 2GM20 will run 2.5 hours on one gallon of diesel fuel; 32.5 hours on the main tank and 25 hours in reserve. We generally cruise under power at 2800rpm and waddle along at about 6.5 knots in flat calm water.
When calculating how far we can get under power I usually use 4 knots because the water is not usually flat calm out there. Sometimes we have found we are going up and down as much as forward.
Looking over my logbook I see that, in over 3000 nautical miles covered, our total fuel consumption for 2011 has been 12.2 gallons
Just wondering how others are managing fuel, other than just pretending the boat is a car and relying on the fuel gauge. Our friend Captain Wendell
who operates a Vessel Assist boat out of Seattle
tells us that out of gas due to faulty gauges is one of the most common reasons for help calls.