Estimating Fuel Consumption
Something that is a concern to many boaters is fuel consumption. Older boats may not have engine monitors that do the calculation automatically and retro fitting an older engine with fuel flow monitors can be expensive and even more so for a diesel engine. Knowing the total fuel a vessel carries there are two calculations to use, gallon per mile (GpM) and gallon per hour (GpH).
In order to get these numbers the use of a trip log is needs to become a habit. Things that need to logged are, engine hours for each engine, generator hours for each generator and nautical miles (nm) per trip and amount of fuel pumped during the next fill-up.
Start the log by filling the fuel tanks completely and before starting the engines or generator, log the starting the hours for each. Starting from the point of fill up, track the nautical miles for each of your trips until you fill up again. First let's get the GpM.
Fuel Filled / Miles Traveled = GpM