Estimating fuel usage
- Thread starter John F
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rough estimate
it depends alot on what rpm you typically run as well as other considerations but 0.5 gph should be close. To state the obvious, a better predictor would be to monitor run time between fillups to calculate actual usage
it depends alot on what rpm you typically run as well as other considerations but 0.5 gph should be close. To state the obvious, a better predictor would be to monitor run time between fillups to calculate actual usage
Fill the tank
then run for an hour or more at cruising revs keeping careful, accurate track of elapsed time. Get back to the dock and carefully measure how much fuel to refill the tank. Then just divide to get gals (or fractions) per hour. After that, use your hour meter to keep track of fuel consumption. I've had plenty of cars where the odometer was the fuel gauge!
then run for an hour or more at cruising revs keeping careful, accurate track of elapsed time. Get back to the dock and carefully measure how much fuel to refill the tank. Then just divide to get gals (or fractions) per hour. After that, use your hour meter to keep track of fuel consumption. I've had plenty of cars where the odometer was the fuel gauge!
An easier way is to simply record
engine hours and fuel used from fill up to fill up. Keep track over a few months and you'll know. Doing the hour trip is harder to actually measure because of the smaller amounts involved and not knowing exactly how much was in the tank. Conceptually it's fine, reality is that it's easier using normal fuel fills at a gas (diesel) dock, since the pump tells you how much you use and the engine hour meter tells you when. I worked up a spreadsheet 9 years ago and use 0.423 gallons per hour. Don's 1/2 gallon per hour is a good starter, but some newer larger engines on sailboats use more than that.
engine hours and fuel used from fill up to fill up. Keep track over a few months and you'll know. Doing the hour trip is harder to actually measure because of the smaller amounts involved and not knowing exactly how much was in the tank. Conceptually it's fine, reality is that it's easier using normal fuel fills at a gas (diesel) dock, since the pump tells you how much you use and the engine hour meter tells you when. I worked up a spreadsheet 9 years ago and use 0.423 gallons per hour. Don's 1/2 gallon per hour is a good starter, but some newer larger engines on sailboats use more than that.
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