M500-3.1.2

Responding to pollution incidents onboard and found at sea

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The Call You Don't Want at 0300

You're the Master of a 450 GT superyacht, twelve miles off the French Mediterranean coast. The engineer calls: a hydraulic line has ruptured in the engine room bilge. An unknown quantity of oil has mixed with bilge water and is now accumulating. The bilge alarm has been running for several minutes and the duty watch is asking whether to pump. At the same moment, the OOW reports a sheen visible astern — whether it originated from your vessel or another is not yet established.

Two separate problems. Two separate legal and operational frameworks. Both land on you.


Pollution Originating From Your Vessel

Stop the source first. Isolate the ruptured line, shut the bilge pump suction before any overboard discharge occurs. Your standing orders and SMS must support this reflex — if the watch pumped automatically before calling you, that is a procedtures failure.

Contain, then assess. Oil-absorbent materials, portable pumps, and a holding tank or IBC are your immediate tools. The Mediterranean is an Annex I Special Area, which means there is no permitted oily mixture discharge into the sea regardless of distance, speed, or 15 ppm threshold — the special area prohibition applies. Retain the contaminated mixture on board for a port reception facility.

Notify. MARPOL and port state requirements, alongside the relevant flag state instrument (for UK-flagged yachts, the Red Ensign Group Yacht Code (REG YC Part A, which superseded LY3) and associated MSNs), require you to report a significant pollution incident. Notify the nearest coastal state authority — in this case the French Maritime Préfecture or CROSS — as soon as practicable. Your SMS will carry the contact details. Log everything: time discovered, estimated quantity, actions taken, notifications made, sea state, position.

Record Book entries. Any transfer, retention, or discharge involving oily bilge water must be entered in the Oil Record Book Part I (required ≥400 GT). Entries signed by the responsible officer, pages countersigned by you.


A Pollution Incident Found at Sea — The Sheen Astern

You cannot confirm source. Do not assume. Your obligations here sit under MARPOL Annex I and under the duty to report to coastal state authorities under UNCLOS and domestic implementing legislation.

Observe and record — position, time, extent of sheen, estimated size in square metres or kilometres, colour and appearance (which helps estimate the oil type), wind, sea state, and any other vessels in the vicinity. Photograph if safe to do so from your vessel.

Report to the coastal state. The coastal state — here France — uses this information to mobilise response resources. Report via VHF Ch 16 to the nearest MRCC/CROSS, then follow their instructions. You are not obliged to take pollution response action yourself beyond reporting, but you should not hamper any response operation.

Your log entry must record that the report was made, to whom, at what time, and what information was provided.


The Master's Decision Framework

  1. Is my vessel the source? → Stop it.
  2. Is anyone at risk? → Safety first; pollution response is secondary to life.
  3. Is retention on board achievable? → In a Special Area, it must be.
  4. Have I notified the coastal state and flag state as required?
  5. Have I made a full, accurate log entry?

An examiner will press you on why you cannot pump the bilge overboard in the Med, and who you call and in what order. Know the answer before you walk in.

Practice questions

oralcore

Your engineer has just reported an oil spill in the engine room bilge — you're 12 miles off the French coast. Walk me through your actions as Master.

recallcore

Why can a yacht of 450 GT not discharge treated bilge water overboard in the Mediterranean, even if the oily water separator is producing an output of less than 15 ppm?

scenariocore

At sea in the Mediterranean you observe a substantial oil slick approximately half a mile off your port beam. Your vessel is not the source. What are your obligations and actions?

scenariostretch

You discover the bilge pump was run by the duty engineer for ten minutes before you were called, and there is clearly a sheen trailing astern from your own vessel. How does this change your actions and what are the consequences you must consider?

recallcore

What entries are required in the Oil Record Book following an oily bilge water incident, and who signs them?

Independent preparatory study aligned to the MCA Master (Yachts less than 500 GT) oral examination syllabus. Not an MCA-approved course and confers no credit toward a Certificate of Competency.