A book or log kept by the Master or Chief Engineer wherein every discharge or escape of oil is recorded.
Every nontanker of 400 GRT and above, and every tanker of 150 GRT and above must have ORB part I ( Machinery space Operation ). All tankers of 150 GRT and above must have ORB part II ( Cargo/Ballast operation )

The ORB must be preserved for 3 years after last entry has been made. The ORB must be completed on each occasion, on tanks to tank basis if appropriate, Entries must be fully recorded without delay and each completed entries must be sign by the officer in charge of the operations concerned. Each completed page must be sign by the Master.

Entries include- any movement of oil in to ship, within ship and out of ship.

Entries in ORB- Part I - Machinery space Operation- All Ship:

  • Ballasting or cleaning of fuel oil tanks
  • Discharging of dirty Ballast or clean water from fuel oil tanks
  • Collection and disposal of oil residue (sludge)
  • Non-automatic discharge over board or disposal otherwise of bilge water which has accumulate in machinery space.
  • Automatic discharge over board or disposal otherwise of bilge water which has accumulate in machinery space.
  • Condition of oil discharge monitoring and control system.
  • Accidental or other exceptional discharge.
  • Bunkering fuel or bulk in lubricating oil.
  • Additional operational procedure or general remarks.

Entries in ORB- Part II- Cargo/Ballast Operation-Tankers:

  • Loading of oil cargo
  • unloading of oil cargo
  • Internal transfer of oil during the voyage
  • Crude oil washing ( COW tankers only)
  • Cleaning of cargo tanks
  • Ballasting of cargo tanks.
  • Discharging Dirty ballast.
  • Discharging of Clean ballast contained in the Cargo tanks
  • Ballasting of dedicated clean ballast tank. ( CBT tankers only)
  • Discharging of ballast from clean ballast tank. (CBT tankers only)
  • Discharge of water from slop tanks in to sea.
  • Disposal of residual and oily mixtures no otherwise required
  • Condition of oil discharge monitoring and control system.
  • Accidental or other exceptional discharge.
  • Additional operational procedure or general remarks.

For vessel engaged in specific trade

  • Loading of ballast water.
  • Re-allocation of ballast water within the ship
  • Ballast water discharged to reception facility.


Machinery space:

  • The ship not within a special area.
  • The ship is proceeding enroute
  • The oil content of the effluent without dilution does no exceed 15 ppm.
  • The ship has in operational:
  • 400 to 10,000GRT -an oil filtering equipment.
  • Above 10,000 GRT - an oil filtering equipment and with arrangement for alarm and automatic stopping any discharge of oily mixture when the oil content of effluent exceed 15ppm.


  • The tankers is proceeding on a voyage
  • The tanker is not within a special area.
  • The tanker is more than 50 miles from nearest land
  • The instantaneous rate of discharge of oil content is not more then 30 litres per nautical mile.
  • The total quantity of discharge is not greater then 1/30,000 of the total quantity of the particular cargo of which the residue formed a part, or in case of existing tankers (before 1980), the total quantity of discharge is not greater then 1/15,000 of the total quantity of the particular cargo of which the residue formed a part
  • The tanker has in operation an oil discharge monitoring and control system and slop tank arrangement. (Clean ballast and processed bilge water (Max 15 ppm) can be discharged within a special area)

Related Terms


MARPOL definition: A noxious liquid substance in category "X" or "Y" with a viscosity equal to or greater than 50 mPa.s at the unloading temperature.


Every non-tanker of 400 GRT and above and every tanker of 150 GRT and above must have a SOPEP in the form a manual.

SOPEP is the summarise flow of chart or checklist to guide the master through the various actions and decisions required in responding to an incident. It should assist the ships crew when dealing with an accidental discharge of oil into the sea. Its primary purpose is to set in motion the necessary actions to stop or minimise the discharge and to reduce its effects on the marine environment. SOPEP is required by regulation 26 of annex 1 of International regulation for prevention of pollution from ship, 1973. Plan must be approved in accordance with this regulation.

The guidelines are comprised of three primary section:

  1. Introduction.
  2. Mandatory provision.
  3. Non Mandatory Provision.


Provide general over view of the subject matter and introduce the reader to the basic concept of the guidelines. The plan are expected to be develop by them.

Mandatory provision:

To ensure that regulation 26 of annex 1 are met.

Non mandatory provision:

Provide other information of the plan. Not required by the regulation. May be required by the local port visited by the ship. It provide additional assistant to the Master when responding in an emergency situation. Also provides on guideline on updating and exercising of the plan.

Plan must be:

  1. Realistic, practical and easy to use.
  2. Understood by ship personnel and shore personnel.
  3. Evaluated, reviewed updated regularly.

Mandatory provision:

  1. Procedure to be followed by the master or other person having the charge of the v/l to report an oil pollution incident.
  2. List of authorities person to be contacted in the event of an oil pollution incident.
  3. A details description of action to be taken immediately by persons onboard to reduce or control the discharge of oil following the incident.
  4. Procedure and point of contact on the ship for co-ordinating ship board activities with national and local authorities in combating the pollution.

Coastal state report:

Convention require that the nearest coastal state should be notified of actual or probable discharge. This required to ensure that coastal states are informed without delay of any incident giving rising of pollution, or threat of pollution of marine environment, as well as of assistance and salvage measures, so that appropriate action may be taken.

Actual discharge:

  1. A discharge of oil due to damage to the ship or its equipment or for purpose of securing the safety of a ship or salving life at sea. Or
  2. Discharge during operation of the quantity or instantaneous rate permitted under the present convention.

Probable discharge

Plan should give the master, guidance to evaluate a situation which, not involving actual discharge, would qualify as a probable discharge and thus report. Report should be made in the following factors: 1. Nature of damage, failure or breakdown of ship, machinery equipment. 2. Ship location and proximity of land or other navigational hazards. 3. Weather, tide, current and sea state. 4. Traffic density.

List of person to be contact:

  1. Coastal state control.
  2. Port state control.
  3. Ship interest contacts.

Guideline to steps to control discharge:

  1. Operational spells
  2. Pipe line leakage.
  3. Hull leakage.
  4. Tank overflow.


A Convention is a treaty between States, which have agreed to be bound by it to apply the principles contained in the convention within their sphere. F.e.: a body of regulations adopted by the IMO which regulate one aspect of maritime affairs


A mixture with any oil content, according to Marpol.


Ballast, which If discharged from a stationary ship in clean calm water on a clear day will not produce visible traces of oil on the water surface nor emulsion below.


A sea area where, for recognized oceanographical and ecological conditions, and in view of traffic, special prevention is required.


Marpol defines following Special Areas with restrictions for dumping overboard:

  • Baltic sea
  • Red sea
  • Gulf sea
  • Antarctic
  • Black sea
  • Gulf of Eden
  • Mediterranean sea

It is forbidden to pump out any sludge or oil residues.


International Convention for the Prevention of Pollution from Ships, 1973 as modified by the Protocol of 1978.

Contains the following Anexes:

Annex I Regulations for the Prevention of Pollution by Oil (entered into force 2 October 1983)

Regulates prevention of pollution by oil from operational measures as well as from accidental discharge.

Annex II Regulations for the Control of Pollution by Noxious Liquid Substances in Bulk (entered into force 2 October 1983)

States discharge criteria and measures for the control of pollution by noxious liquid substances carried in bulk.

Annex III Prevention of Pollution by Harmful Substances Carried by Sea in Packaged Form (entered into force 1 July 1992)

General requirements for the issuing of detailed standards on packing, marking, labelling, documentation, stowage, quantity limitations, exceptions and notifications.

Annex IV Prevention of Pollution by Sewage from Ships (entered into force 27 September 2003)

Requirements to control pollution of the sea by sewage.

Annex V Prevention of Pollution by Garbage from Ships (entered into force 31 December 1988)

Covers different types of garbage and specifies the distances from land and the manner of disposal.

Annex VI Prevention of Air Pollution from Ships (entered into force 19 May 2005)

Sets limits on SOx and NOx emissions from ship exhausts and prohibits deliberate emissions of ozone-depleting substances; requires technical and operational energy efficiency measures aimed at reducing greenhouse gas emissions from ships.


A log where discharge or escape of oil is recorded.


The senior engineer officer responsible for the satisfactory working and upkeep of the main and auxiliary machinery and boiler plant on board ship.

Related questions

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