Here are the key points on carrying extra fuel in fuel bladders:
• Know exactly how many gallons of diesel your standard fuel tanks can hold — calibrate the sight glasses for accuracy and use a flow meter to verify volume.
• Have a means to draw out and consume all of the fuel in your standard tanks, you need to be able to use every last drop.
• Do several runs at full load to measure your fuel burn underway at various rpm so you can calculate your range — totals for engine(s) and generator(s) at different speeds.
• Create an accurate rpm/fuel burn chart so you can easily reference your consumption and range.
• Plan your trip in advance based on point-to-point mileage distance (add 10 percent to allow for wave/seas and steering offsets) and know in advance what fuel replenishment resources are available upon arrival.
• Calculate your fuel consumption on your passage to arrive at your destination with a minimum of 10 percent in reserve — you can’t afford to run out and don’t want to coast in on fumes.
• Start your trip off slowly so you reach the halfway point with more than half of your fuel supply remaining to complete the trip.
• Supplemental fuel reserves must be properly installed so they are secured in place, minimally affect at-sea rolling and have a low center of gravity.
• Position your reserve fuel so it can easily refill your standard tanks without allowing saltwater ingress and time your refills during calm sea conditions.