Digital fuel gauges provide instant data to your fingertips; modern seamanship dictates you analyze it. Look at the test numbers on every boat we've ever reviewed. Note the rpm, speed, gallons per hour, miles per gallon, and range. All numbers you can use with your boat, provided it has similar power, to approximate when planning a trip. Note also that our range calculations are based on 90 percent of fuel capacity, something you should employ when calculating for your own boat.