If you use diesel fuel, now might be the time to make the switch to a biodiesel blend. Made from renewable resources such as soy or vegetable oils, it burns cleaner than regular diesel, is non-toxic and biodegradable in its pure form, and is free from sulfur and aromatics.

The Boat U.S. Foundation suggests using biodiesel fuel as an additive, mixing it with petroleum diesel. The recommendation is for a 20 percent blend with 80 percent petroleum diesel, a combination that requires no engine modification and results in a less offensive exhaust odor, reduced emissions, improved lubrication, and cleaner injectors, fuel lines, pumps and tanks. (For higher blends of biodiesel fuel, you will probably need to modify the fuel lines.)

Despite improvements in performance and emissions, biodiesel fuel does have some drawbacks, particularly at higher blend levels. For one thing, rubber gaskets and hoses may degrade more rapidly over time. For another, although biodiesel fuel cleans tanks and lines more efficiently than straight petroleum fuel, the byproduct is extra residue that has to go somewhere – and that somewhere is the fuel filter. So with biodiesel fuel, you can expect to change your fuel filters more frequently. You also need to use soap and water to wash down any spills as soon as they occur because the solvent properties of biodiesel fuel can harm teak and gelcoat.

The bottom line is that while biodiesel fuel has some modest drawbacks, it is safer for air and water than pure petroleum fuel, burns cleaner, improves performance and reduces harmful emissions. If you're looking for ways to go green, this one is surely worth consideration.

- Linda Hoff