10/23/2025
⚓ ODME System (Oil Discharge Monitoring Equipment) – Operation & Simulation Test
🚢 The ODME system (Oil Discharge Monitoring & Control Equipment) is a mandatory installation on all oil and chemical tankers. It monitors, calculates, controls, and records any oily water discharge from the cargo tank area, ensuring full compliance with MARPOL Annex I Regulation 34.
This guide explains the ODME system’s operation, components, alarms, IRD formula, simulation test, and maintenance, featuring a real onboard Oilcon Mark 6M simulation test.
⸻
🎯 Why the ODME System Exists
“The purpose of ODME is to discharge as much water as we can and not as much oil as we are allowed.”
The ODME system ensures that all discharges are safe for the marine environment by automatically controlling and recording oil content and discharge rate.
⸻
📜 MARPOL Annex I Requirements
Discharge of oily mixtures from the cargo tank area is prohibited unless all conditions are met:
✅ Ship is en route and more than 50 NM from land.
✅ Ship is outside MARPOL Special Areas.
✅ Instantaneous Rate of Discharge (IRD) ≤ 30 L/NM.
✅ Total oil discharged ≤ 1/30,000 of total cargo.
✅ The ODME system must be operational, auto-stopping, and recording.
🧭 Special Areas: Mediterranean, Baltic, Black, Red, Gulfs Area, Gulf of Aden, Oman Area, Southern South African Waters, North West European Waters, Antarctic.
👉 Reference: IMO MARPOL Convention
⸻
🧩 ODME System Components
1️⃣ Sampling Unit / Sample Cell
2️⃣ Oil Content Meter (OCM)
3️⃣ Flow Meter
4️⃣ Speed Input
5️⃣ Control & Calculation Unit
6️⃣ Three-Way/Overboard Valve
7️⃣ GPS Position Input
8️⃣ Printer / Data Logger
9️⃣ Alarm & Interlock System
⸻
📐 Instantaneous Rate of Discharge (IRD)
Formula:
IRD (L/NM) = (Oil Content (ppm) × Flow Rate (m³/h)) ÷ (Speed (knots) × 1000)
➡️ If IRD > 30 L/NM, the ODME system automatically stops discharge and diverts flow to slop.
⸻
🛠️ Standard Operation of ODME System
Follow the vessel’s SMS, P&A Manual, and Master’s standing orders.
✅ Confirm ship en route, >50 NM, outside special area.
✅ Check calibration, sensors, printer, and GPS input.
✅ Line up discharge through ODME; keep recirculation ready.
✅ Start slowly; monitor ppm and IRD.
✅ Any alarm = auto-stop + divert to slop.
✅ Record printout in ORB Part II.
⸻
🧪 ODME System Simulation Test – Oilcon Mark 6M
Simulation is done before any discharge to verify alarms, valves, and logic.
Step-by-Step:
1️⃣ Set ODME to Simulation mode.
2️⃣ Switch Speed/Flow to manual; maintain IRD < 30 L/NM.
3️⃣ Check IRD calculation is stable.
4️⃣ Command Open Overboard Valve → Overboard opens, Slop closes.
5️⃣ Trigger Alarms:
⚠️ High PPM
⚠️ High IRD
⚠️ Total Discharge Limit
6️⃣ Verify: Alarms cause auto-stop, overboard closes, slop opens.
7️⃣ Confirm all alarms printed.
8️⃣ Record “ODME Simulation Test carried out – alarms verified” in ORB Part II.
⸻
⚙️ Inbuilt Self-Test
Oilcon Mark 6M includes Self-Test mode to check all sensors, relays, and printer.
Always run before simulation or discharge.
⸻
✅ Quick Checklist (Converted to Text)
✅ IRD below 30 → System operating normally
✅ High PPM Alarm → Auto-stop, Overboard closes, Slop opens
✅ High IRD Alarm → Auto-stop, Alarm recorded
✅ Total Quantity Limit → System stops discharge
✅ Manual Stop → Overboard closes, Slop opens
✅ Valve Feedback → Matches actual valve position
✅ Printer Log → All events correctly recorded
✅ Self-Test → No errors found
💡 Always test before using ODME — one short test avoids MARPOL violations & detentions.
⸻
🚨 ODME System Alarms
• High PPM/IRD – stop discharge & settle slops.
• Flow fault – check valve/air supply.
• Valve fail – inspect solenoid.
• Printer error – replace paper.
• GPS/Speed fail – stop until fixed.
• Sample cell dirty – rinse & clean.
⸻
🧽 Maintenance & Calibration
✔️ Rinse sample cell with fresh water after use.
✔️ Weekly alarm & print test.
✔️ Annual calibration by service tech.
✔️ Keep ODME logs ≥ 3 years.
⸻
🧾 Record Keeping
• Enter all operations & tests in ORB Part II.
• Attach printouts.
• Sign as per SMS.
⸻
🌊 Environmental Responsibility
The ODME system is not just compliance — it’s a commitment to protect our oceans 🌍💙
⸻
🎥 Watch the Full ODME Simulation Test (Oilcon Mark 6M)
📺 YouTube Link 👉 https://youtu.be/2cyIphLQ8Oo?si=nb45iOzZtl2Sh1bj
📖 Read Full Article on Website:
👉 https://merchantnavylife.com/odme-system-operation-simulation-test/
⸻
🔗 Related Posts
• How to Perform a Winch Brake Holding Test Onboard Ship
• Second Generation EPIRB Tron 60AIS Guide
• Understanding ECDIS – Navigation System Basics
⸻
⚠️ Disclaimer
This post is for educational purposes only. Always follow Company SMS, MARPOL, Flag, and Class rules. Merchant Navy Life is not liable for misuse or non-compliance.
⸻
📌 Hashtags