MARPOL Annex - I , International Regulation for Prevention of Pollution by Oil

The transportation of oil as cargo and the use of oil as fuel in marine diesel led o waste oil being generated as residues in tanks after discharging and also from the main engine. the residues in tanks were discharged in to sea either during cleaning or ballasting the tanks and discharging the dirty ballast in to sea. 

Special Area of MARPOL Annex - I 

1. Mediterranean Sea
2. Baltic Sea 
3. Black Sea
4. Antarctic Sea
5. Red Sea 
6. Gulf of Aden 
7. Gulf Sea 
8. Southern South African Water
9. Oman area of the Arabian Sea
10. North West European Water

Control of Discharge of Oil :

👉 Discharging Criteria of Oil From the Cargo Spaces :

                        The discharge of  oil or oily water mixture from the cargo area of tanker is prohibited to be discharged into the sea except when all the following condition are satisfied ,

1. The Tanker is not in a Special Area.
2. The Tanker is more than 50 NM from the nearest land.
3. The Tanker is proceeding En-route.
4. The instanteous rate of discharge does not exceed 30 Liters/ nautical mile.
5. The total quantity of Oil Discharged is not more than 1/30,000 of the quantity of the last cargo.
6. The Tanker has in operation an ODMC and a Slope Tank arrangement.

 

👉 Discharging Criteria of Oil from Machinery Spaces :

Any discharge of Oil or Oily Mixtures from ships of 400 GRT and above is prohibited except when the following are satisfied ,

1. The Ship is en-route.
2. Oily Mixture is processed through Oil Filtering system.
3. The Oil Content in the Mixture does not exceed 15 PPM.
4. The Oily Mixture does not Orignate from pump room bilges in oil tanker.
5. In case of oil Tanker the oily mixture is not mixed with oil cargo residues.

👉 Oil Record Book :

Requirements : 

All ship of 400 GRT and above must have a Oil Record Book. (part-1)

All Oil Tanker of 150 GRT and above must have Oil Record Book. (part - 1&2)

Part - I : For Machinery Spaces 

Part - II : For Cargo/Ballast Tank 

All operation involving oil are to be recorded in the Oil Record Book.

Entry in ORB :

PART - I :

1. Ballasting or Cleaning of Oil fuel tanks.
2. Discharge of dirty ballast or cleaning water from oil fuel tanks.
3. Collection and disposal of oily residues .
4. Discharge overboard or disposal otherwise of engine room bilge water .
5. Bunkering of fuel or bulk lubricating.

PART - II :

1. Loading of oil cargo.
2. Internal transfer of oil cargo during voyage.
3. Unloading of oil cargo.
4. Ballasting of cargo tanks and dedicated clean ballast tank.
5. Cleaning of cargo tanks including crude oil washing .
6. Discharge of ballast except from segregated ballast tank.
7. Discharge of water from slope tank.
8. Closing of all applicable valves necessary for isolation of dedicated cargo tank.
9. Disposal of residues.

OIL RECORD BOOK KEPT FOR 3 YEARS.

👉 Slope Tank :

                            It is specially designed tank, used to store the oil left over after tank cleaning and other oil mixture of cargo oil and residues of ship's cargo together with the water.

Requirements : 

Tanker ≥ 150 GRT - 1 Slope tank

Tanker > 70000 DWT - 2 Slope tank

Capacity of slope tank must be 3% of the cargo carrying capacity of the ship.

👉 ODMC (Oil Discharge Monitoring & Control System)

                                The ODMC must be follow the guidelines specified by the IMO and must be approved by the Administration . It must provide

1. Oil tanker of 150 GRT and above shall be fitted with ODMC.
2. A continuous record of the discharge of oil in litters/nautical mile.
3. The total quantity discharged.
4. The oil content and the rate of discharge of effluent.
5. Record to be kept for at-least 3 years.
6. Automatically stop the discharge in case instantaneous rate of discharge exceed.
7. Discharge should be stopped in case of system failure.
8. Alarm raises if oil content exceed and rate of discharge exceed.

👉 Segregated Ballast Tanks: 

                                A segregated ballast tank is permanently allocated for the carriage of ballast or cargo other than oil or noxious substances , which is completely separated from the cargo oil and oil fuel system i.e. having its own pump and piping system.

Requirement : Crude oil tanker of 20000 DWT and above , Product tanker of 30000 DWT and above shall be fitted with segregate ballast tanks.

👉 Clean Ballast : 

                            Clean ballast means the ballast in a tank which, since oil was last carried therein has been so cleaned so, if it were discharge from ship which is stationery into a clean calm water on clear day would not produce visible traces of oil on surface of water and if discharged through the ODMC oil content does not exceed 15 PPM and not visible traces.