Answer
If the Bilge Holding Tank reaches 100% capacity, it creates an immediate environmental, operational, and statutory risk. A systematic action plan must be executed:
Step 1: Immediate Containment (Stop Inflows)
- Stop Automatic Transfers: Immediately switch all engine room bilge transfer pumps and automatic bilge wells from "AUTO" to "MANUAL / OFF".
- Isolate High-Inflow Sources: Inspect and isolate non-essential drains feeding the bilges (e.g., boiler blowdowns, air cooler condensate drains, fresh water generator dumps, or stern tube gland leakages).
Step 2: Evaluate Vessel Position & MARPOL Annex I Status
Determine the vessel’s operational location:
- Option A: At Sea (En Route)
- Start the 15 ppm Oily Water Separator (OWS) with the automatic 3-way stopping valve and continuous 15 ppm oil content monitor active.
- Process and discharge compliant water overboard to reduce tank level, ensuring strict monitoring throughout.
- Option B: In Port, Anchored, inside a Special Area, or OWS Malfunctioning.
- Overboard discharge is strictly prohibited. Proceed to Step 3 for internal transfer or shore disposal.
Step 3: Internal Transfers (If Overboard Discharge is Restricted)
If the vessel cannot process bilges overboard:
- Transfer to Designated Waste Tanks: Transfer oily bilge water to an empty Oily Sludge Tank, Waste Oil Tank, or Drain Tank using approved, permanent piping arrangements.
- Temporary Bilge Well Retention: If waste tanks are full, retain water in large engine room bilge wells, ensuring no oil reaches electric motors or pump suctions.
- Strict Logging: Log the internal transfer immediately in the Oil Record Book (ORB) Part I under Code C (Item 11) or Code I (Additional Operational Procedures).
Step 4: Master Notification & Shore Reception
- Inform the Master of the tank status.
- If en route and OWS cannot cope with inflow, request a shore reception facility (sludge/bilge barge or truck) at the next port of call.
Step 5: Root Cause Investigation & Rectification
- Trace and repair the source of excessive water entry (e.g., leaking seawater pump mechanical seals, pipe fractures, cooler leaks, or leaking heat exchangers).