Oil or Fuel in the Bilge: Safe, Legal Cleanup

Smell it and look at it, from a safe position:

• Gasoline: sharp, strong fuel smell, thin and clear or slightly colored. Follow the safety note above first.
• Diesel: oily fuel smell, thin, often reddish or amber.
• Engine or gear oil: thicker, brown or black. Gear lube smells strongly of sulfur.
• Hydraulic or transmission fluid: often red or pink and thin.

What it is tells you where to look for the leak later.

If the boat is not taking on water, switch the automatic bilge pump to off while you clean up, so the float switch does not pump oil out of the boat. Put a note on the helm ("Bilge pump OFF") so you remember to turn it back on before you leave. If water is coming in, leave the pump on and call for help; safety comes before the spill.

A rainbow or silvery film around the boat means oil already got out.

• Call the National Response Center (1-800-424-8802) and the marina office.
• Be ready to say where you are, what spilled, roughly how much, what it looks like and when it happened.
• The NRC is staffed around the clock by Coast Guard personnel, but it is a reporting center, not a cleanup crew: it passes your report to the EPA or Coast Guard, who decide whether a response is needed. Calling it does not replace containing what you can and telling the marina.
• If you have an absorbent boom or pads aboard, lay them on the water to soak up the film. BoatUS notes you can start with contained absorbents while you wait for instructions, as long as you recover them and dispose of them properly.
• Do not add soap or any "spill dispersant" product to the water.

Use oil-only absorbent pads (sometimes labeled "oil-only" or "hydrophobic"). They pick up oil and fuel and leave the water behind, so you are not wasting pads on bilge water.

• Lay pads flat on the oil and let them sit a minute or two.
• Lift each pad straight into a plastic bag. Do not wring it out into the bilge or overboard.
• Use fresh pads until they come up clean.
• In a deep sump, drop in an absorbent pillow or sock and leave it to collect the rest.

If there is more oil than pads can handle, or a lot of oily water, do not pump it out of the boat. Sailors for the Sea suggests removing it at a bilge pumpout station. Many marinas have one, and some offer a bilge cleaning service. You can also pump or bail the oily water into sealed containers and take them to a used oil collection site that accepts oily water. Ask first.

Used pads, socks and pillows are oily waste. Discard them as your state and local rules require. Many marinas, oil change shops and household hazardous waste sites accept them. Do not throw them in the marina dumpster unless the marina says it is allowed.

• Diesel or oil pads: double-bag them and keep them out of the sun until disposal.
• Gasoline pads: they give off flammable vapor. Keep them outside the boat in a closed metal can, away from heat and sparks, and take them to a hazardous waste site.

After the pads, a thin film usually remains. Wipe it with more pads or rags. If you use a bilge cleaner product, treat the bilge water afterward as oily water: it still must not be pumped overboard. Remember that a cleaner that makes oil "disappear" is only mixing it into the water.

When the bilge is clean, switch the bilge pump back to automatic and test it with clean water. A working bilge pump matters far more than a spotless bilge.

Dry the engine area and bilge, put a clean white pad or paper towels under the engine, run the engine (with cooling water and good ventilation) and look for fresh drips. Common sources:

• Oil filter not tight, or a double gasket after an oil change
• Oil drain hose or plug, valve cover gasket, oil pressure sender
• Transmission or V-drive cooler lines and seals
• Spills during an oil change that ran down into the bilge

Fuel in the bilge is more serious than oil because it means a fuel system leak. Look at:

• Fuel filters and water-separator bowls and their drain valves
• Fuel hoses and clamps, especially at the tank, the filter and the engine
• Diesel injector lines and return lines
• The tank fill and vent hoses

If you find a fuel leak, or cannot find the source of a fuel smell, do not run the engine. Have a marine mechanic fix it before you use the boat.

Hydraulic steering, power trim pumps inside the boat, the generator, and hydraulic hoses for trim tabs can all leak into the bilge. Match the color and smell to the fluid you found in step 1.

On sterndrives and inboards with power steering, a common culprit that owners report is the power steering hose, usually where the crimped metal ends rust, or a corroded fluid cooler. With the engine running and cooling water supplied, have a helper turn the wheel lock to lock while you watch the hoses, the pump and the steering cylinder with a flashlight, keeping your hands and hair well clear of belts and pulleys. Mark the reservoir level so you can tell whether it keeps dropping. If the steering gets heavy or the level falls fast, get it repaired before the next trip (see the sterndrive power steering guide).

• Keep an oil-absorbing bilge sock under the engine, secured so it cannot block the bilge pump intake or float switch, as BoatUS advises.
• Put an absorbent pad under the oil filter and in a drip pan during oil changes.
• Change oil with an extraction pump and a bag over the filter.
• Consider a bilge oil filter or oil/water separator that cleans the water before the pump discharges it.
• Replace the bilge sock when it is saturated, and dispose of it properly.