Fuel consumption represents approximately 80% of your engine operating expenses over the life cycle of a new engine. MarineDiesel engines are designed to be as fuel efficient as possible, providing the most power and torque for the fuel consumed.
However, as an operator, there are things that you can do to minimize fuel consumption and expense, often not directly related to the engine.
1. Keep an eye on the vessel weight. Boats are designed to deliver a specific level of performance based on a projected full displacement of the boat. If you add weight to the boat, whether it is extra guns or ammunition on a military craft or extra passengers on a commercial vessel, extra weight reduces speed and forces the engine to consume more fuel in order to provide the same level of performance.
2. Watch your throttle. Most engines are rated at a cruising speed of roughly 80% to 90% of maximum throttle (WOT). This cruising speed, varying by manufacturer, is the point where the engine is operating at its’ most efficient level. Save WOT for when you really need it.
3. Watch your trim. Especially on fast boats with planning hulls. Most high speed craft are designed with level operation in mind. Trim too far down, and you increase resistance (and fuel consumption). Trim too far up, and you are decreasing the efficiency of the propulsion (and increasing resistance).
4. Clean your hull. Fouled or dirty hulls can increase vessel resistance as much as 5% or more, depending on the amount of fouling. Increased resistance results, as does higher fuel consumption.
5. Check your propellers and propulsion. Damaged propellers rapidly lose propulsion efficiency. Likewise, replacing propellers with mismatched pitch or other specifications will impact your bottom line immediately. Never replace propeller types unless you truly understand what you are doing.
6. Follow your manual’s maintenance schedule. Clogged filters, leaking seals and gaskets, improper exhaust, and blocked intakes all reduce engine efficiency and increase operating cost.