Module 17 - Marine Environment
Oil and Fuel Pollution
What you will learn
Prevent routine oil and fuel releases and carry out a stop-contain-report response without using detergent or dilution to hide pollution.
Small-yacht oil control begins with finding leaks, retaining oily material aboard and preparing the fuel transfer so it can be stopped before a drip becomes a spill.
MCA guidance says oil should be retained aboard for disposal to shore reception facilities. A small pleasure vessel is not normally required to install approved oily-water separating equipment, so its practical default is not to pump oily bilge water overboard. Find and stop the leak, recover free oil with suitable absorbent material or equipment and follow the marina or waste facility's disposal route.
Prevention includes a clean bilge that makes new leaks visible, a drip tray under the engine, sound hoses and joints, an accessible spill kit and a crew member who knows how to stop the transfer. Before refuelling, confirm the correct filler and expected quantity, extinguish ignition sources, close openings against petrol vapour where relevant and keep the nozzle attended. Slow the delivery before the tank is full; do not rely on fuel appearing at a vent as the stopping signal.
If fuel escapes, stop the transfer and close the source if that can be done safely. Raise the alarm, protect drains and water, deploy the facility's absorbent pads or booms, and contact the fuel berth or harbour authority immediately. Detergent, hosing, propeller wash or dilution spreads or disguises the pollutant rather than recovering it and may make the response more harmful.
Worked example
During refuelling, diesel appears around the deck filler and starts moving towards a cockpit drain.
- 1Stop the nozzle or delivery pump immediately and close the source if it is safe to do so.
- 2Warn the crew and fuel berth, keep ignition sources controlled and prevent the spill reaching the drain or water.
- 3Use oil-selective absorbent material or the facility's response equipment; do not add detergent or wash the deck down.
- 4Report the release to the harbour or marina as required and arrange disposal of contaminated absorbents through its procedure.
Sense check: The response should leave the fuel stopped and physically recovered or contained—not merely made less visible.
Prepare the transfer before opening the filler
The gauge is unreliable and the crew do not know how much fuel the tank will accept.
1. Estimate
Use the tank capacity, recent engine use and a conservative fill quantity rather than guessing from the gauge alone.
2. Protect
Position absorbent material, close vulnerable openings, control ignition sources and nominate the person who can stop delivery.
3. Monitor
Attend the nozzle, listen and watch for tank or vent changes, and slow well before the expected full level.
Sense check: If nobody can state who stops the flow or where the spill kit is, the yacht is not ready to refuel.
Common mistake or limitation
- A sheen made invisible by detergent or dilution is still pollution; the job is to stop and recover the contaminant.
- Absorbent pads manage escaped oil but do not replace finding and repairing the leak that contaminated the bilge.
Recap
- A small yacht's safe default is to retain oily waste and dispose of it ashore.
- Good refuelling controls make overfill less likely and let one person stop the transfer immediately.
- A spill response stops the source, protects water and drains, contains the fuel and follows the harbour reporting plan.
Optional quick check
Section 2 of 7
Diesel starts running towards a deck drain during refuelling. What should happen first?
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