2.13 OIL DISCHARGE MONITOR AND THE OIL RECORD BOOK
In June of 1990, the master of a 200,000 DWT VLCC was arrested by Piraeus
port authorities and accused of having caused serious pollution of the
sea by discharging oil residues. The spill was discovered on June 7th
and reported at the time to be 10 miles in length, 23-30 meters in width
and 10 centimetres in thickness. (This would be equivalent to a volume
of oil of 50,000 cubic meters!) The pollution allegation was based on
four vertical traces of oil residues on the vessel's port side when it
arrived in Piraeus. State laboratory tests matched slop tank residues
with samples of the spilled oil. The vessel's oil record book noted that
the vessel pumped out ballast in the area at the time of its passage.
Regrettably, the vessel's oil discharge monitor was not in operation at
the time of de-ballasting. Four bank guarantees were lodged in order to
avoid arrest of the vessel and for the release of the master on bail.
Without the ODM in operation and a properly annotated record of the
CBT discharge, a tanker cannot defend itself against an accusation that
it discharged oil to the sea at a particular time and place.
2.13.1 The oil discharge monitor
Regulation 15 of Chapter II of MARPOL 73/78 requires that tankers be
fitted with an approved oil discharge monitoring and control system.
The system may operate on one of a number of principles, but must be
certified to meet the performance specifications adopted by the IMO,
including a recording device indicating the oil content and rate of
ODM records must indicate the date and time of operation. Records must
be maintained for inspection for three years. The ODM must be used when
there is any discharge of effluent to the sea and must be arranged to
automatically stop the discharge when the instantaneous rate of oil
discharge is more than that permitted by regulation. Failure of the
ODM shall also stop the discharge and shall be noted in the oil record
book. Beginning on 4 April 1993, a tanker with a defective ODM may undertake
only one ballast voyage (using manual alternatives of determining oil
content of its effluent), before making repairs to the ODM.
Oil discharge monitor and control system.
A complete and detailed operations manual must be provided for routine
ODM operations and for manual procedures to be used in the event of
ODM malfunction. Each officer should become familiar with the principle
and method of operation of the ODM on his ship, and understand the most
common modes of failure of the equipment. Officers must also understand
the principle and method of operation of the ship's oil/water interface
ODME print-out from one hour after the start of
slop tank decanting per oil record book entry.
Use of the ODM is required when discharging ballast from cargo or CBT
tanks, slop tanks, or treated bilge water. Dirty ballast from cargo
tanks, or SBT which is suspected to contain oil, must be discharged
overboard above the ship's water line unless: The surface of the ballast is examined and found free from oil immediately
The tanks have settled for a sufficient time to permit suitable separation,
the level of the oil/water interface has been determined using an approved
interface detector and the discharge is by gravitation, or
The discharge line is fitted with a part-flow piping system which is under
observation throughout the discharge.
2.13.2 The oil record book
Regulation 20 of Chapter II of MARPOL 73/78 requires every oil tanker
(of 150 gross tons or more), to carry and maintain Parts I and II of
the oil record book in the form specified by appendix III of the regulations.
Part I is arranged to record machinery space operations. Part II is
designed to record cargo or ballast operations on oil tankers. Each
completed entry in the oil record book must be signed and dated by the
officer or officers in charge. Each completed page must be signed by
The entries are arranged according to a letter and number code. Entries
must be completed for each tank separately. Entries shall be made without
delay. The entries shall be in the official language of the flag state.
Vessels having an IOPP certificate must also make entries in English
or French. The oil record book must be kept readily available for inspection
at all times. The required oil record book entries are:
a Loading of oil cargo.
b Internal transfer of oil cargo during voyage.
c Unloading of oil cargo.
d Crude oil washing (COW tankers only).
e Ballasting of cargo tanks.
f Ballasting of dedicated clean ballast tanks (CBT
g Cleaning of cargo tanks.
h Discharge of dirty ballast.
i Discharge to water from slop tanks into the sea.
j Disposal of residues and oily mixtures not otherwise
k Discharge of clean ballast contained in cargo tanks.
l Discharge of ballast from dedicated clean ballast
tanks (CBT tankers only).
m Condition of oil discharge monitoring and control
n Accidental or other exceptional discharges of oil.
o Additional operational procedures and general remarks.
Where an entry cannot be properly coded, it should be recorded in
the national language of the officer and in English or French. National
(port state) authorities may ask to inspect the oil record book at any
time and have certified copies made on request.
A review of some oil record books has shown examples of entries which,
if carefully reviewed, incriminated the officer in charge for violation
of the MARPOL regulations. These entries were then signed by the master!
Great care must be taken to make the entries correctly, in a way which
accurately reflects the care taken to avoid pollution.
Owners/operators of tankers should provide detailed
advice regarding oil record book entry procedures.
An example of a simplified series of oil record book entries for a typical
voyage by a SBT tanker follows:
After decanting slops for 12 hours, the tanker began decanting the slop
tank at 15.00 (Zulu). At 16.12 the pumping rate was reduced from 1000
H3/hr to 375 M3/hr (for an average rate of 750 M3/hr).
2.13.3 Oil discharge limitations The tanker is not within a special area.
Regulation 9 of Chapter II of MARPOL 73/78 prohibits any discharge of
oil or oily mixtures into the sea by tankers except when the following
conditions are satisfied:
The tanker is more than 50 nautical miles from the nearest land.
The tanker is proceeding en route.
The instantaneous rate of discharge of oil content does not exceed 60
litres per nautical mile.
The total quantity of oil discharged into the sea does not exceed:
existing tankers 1/15,000 of the total quantity of the particular cargo of which the residue formed a part and
b For new tankers
1/30,000 of the total quantity of the particular cargo of which the
residue formed a part
The tanker has in operation and oil discharge monitoring and control
system and a slop tank arrangement as required by Regulation 15.
Control of discharge of oil from cargo tank areas
of oil tankers.
*Special area requirements take effect in the
Mediterranean Sea, Black Sea and Baltic Sea areas from the day of
entry into force of MARPOL 73/78 and for the Red Sea and Gulf areas
from the date established by IMO.
**'Clean ballast' is the ballast in a tank which has been so cleaned
that the effluent therefrom does not create a visible sheen or the
oil content exceed 15 ppm (for the precise definition of 'clean ballast',
see regulation 1(16) of MARPOL 73/78)
2.13.4 Special areas and prohibited zones Mediterranean Sea area
Regulation 10 of Chapter II of MARPOL 73/78 established the following
special areas in which no operational discharge of oil or oily mixture
from tankers is permitted.
Baltic Sea area
Black Sea area
Red Sea area
Gulf of Aden
The exact delimiting boundaries of these areas are given in Regulation
10, Section (1).
Within the special areas, any discharge of oil or oily mixtures by tankers
is prohibited. Reception facilities are provided for the cargo residues
of tankers trading exclusively within special areas.
2.13.5 Prohibited zones
While the IMO 'special areas' protect some international waters, other
nations have established regulations to protect their national waters
by declaring 'prohibited zones'. In some cases, such zones apply only
to national flag vessels.
The most significant 'prohibited zone' is the 50 miles-from-land exclusion
contained in MARPOL Regulation 9 (section 2.13.3 above). The 1962 'International
convention for the prevention of pollution of the sea by oil' established
100 mile prohibited zones around the coasts of Canada, Greenland and
Iceland, and an extensive 'NE Atlantic prohibited zone' embracing the
coasts of Norway, Ireland, the United Kingdom, Western Europe, Spain
and Portugal and extending (like a funnel pointing west), as far west
as 40 degrees longitude. The United States has also declared a 100 mile
prohibited zone around its coast.
Within the prohibited zones, the discharge of persistent oils, or oily
water mixtures containing more than 100 parts per million of persistent
oil is prohibited. Special areas or prohibited zones do not apply to
segregated or clean ballast discharges.
2.13.6 Oils spills en route Type and name of the ship.
Any oil spilled en route must be reported by radio to the nearest
coastal state as soon as possible. The report must include:
Radio frequency/channel(s) guarded.
Name, address and telex numher of the owner and operator.
Date and time (UTC) of the spill.
Position, course and speed of the ship at the time of the spill.
Description of the incident.
Damages sustained by the ship.
Type of oil involved and the amount spilled.
Other cargo on board.
Follow-up reports must be submitted as requested by the coastal state.