Oil Discharge Monitoring and Control Systems Failures

The Republic of the Marshall Islands issued a marine notice to provide procedures to be followed in the event of an Oil Discharge Monitoring and Control Systems (ODMCS) failure.

MARPOL Regulation I/31, details the requirements for the automated use of the oil discharge monitor with slop tanks during the cleaning operation of cargo tanks of existing tankers. Provisions must also be made for emergency manual control of the effluent discharge in case of failure of the ODMCS. IMO Resolution MEPC.108(49), as amended, contains the full revised guidelines and specifications for oil discharge monitoring and control systems for oil tankers constructed on or after 01 January 2005, including the 2013 amendments set forth in MEPC.240(65). For tankers constructed prior to 2005, the equipment and systems may comply with the earlier standards contained in IMO Assembly Resolution A.586(14).

MARPOL Regulation I/31.2 states:

“Any failure of this monitoring and control system shall (automatically) stop the discharge. In the event of failure of the oil discharge monitoring and control system, a manually operated alternative method may be used, but the defective unit shall be made operable as soon as possible. Subject to allowance by the port State authority, a tanker with a defective oil discharge monitoring and control system may undertake one ballast voyage before proceeding to a repair port.”

Further, per MARPOL Regulation I/36.6, all failures of the oil discharge monitoring and control system shall be noted in Part II of the Oil Record Book. Section 6.11.1.1 of Resolution MEPC.108(49), as amended, clarifies these reporting requirements to ensure complete and proper reporting of any such instances.

Per Report MEPC 36/22, paragraph 9.40, the phrase

“before proceeding to a repair port” means a laden voyage following a ballast voyage. If the ODMCS fails during tank cleaning while the tanker is en route to a loading port, the cleaning may continue as long as a planned and documented manual method of monitoring and logging the discharge is being utilized. The vessel may then make one (1) loaded voyage after which the ODMCS must be repaired at the discharge port. If the repairs cannot be done at the discharge port, then the vessel may be allowed one (1) voyage directly to a port where ODMCS repairs can be accomplished.

Further, per MEPC 36/22, paragraph 9.40,such a voyage should only be acceptable under the following conditions:

1. an oil discharge monitoring method must be manually operable;
2. the vessel must provide documentary records in the Log Book or the Oil Record Book or in the vessel’s planned maintenance record that the system has been maintained in accordance with the manufacturer’s recommendations;
3. the equipment has been utilized and records are available which verify the use of the unit during all ballast discharges prior to the present functional defect and that this defect has been duly recorded in the Oil Record Book;
4. prior to arrival at the unloading port, the failure has been reported to the authorities (port State and classification society); and
5. that every reasonable effort has been made to repair the defective unit prior to the vessel departing from the unloading port.

Manual Monitoring Procedures

The manual monitoring of the effluent discharge must be made during daylight hours using the oil/water interface detectors (MARPOL Regulation I/32) as well as following the ODMCS manufacturers instructions for manual operation (MARPOL Regulation I/31.4) together with the procedure recommended by MEPC.108(49), as amended, as follows:

1. oil content meter or sampling system: location and measurement of the oil/water interface using the equipment as required in MARPOL Regulation I/32, visual observation of the surface of the water adjacent to the effluent discharge and recording the relevant data in the Oil Record Book Part II in sections H and I;
2. flow meter: pump discharge characteristics such as the gallons or liters per minute to be considered in the calculation and recorded to check accuracy of flow meter;
3. ships speed device: main engine revolutions per minute as well as the propeller diameter, pitch and slip to confirm ship travel in nautical miles to be recorded;
4. processor: manual calculation and manual recording of oil content vs. water outflow to confirm total out flow; and
5. overboard discharge control: manual operation of pumps and valves to be utilized together with all the above to confirm that an instantaneous rate of discharge of oil does not exceed 30 liters per nautical mile.

Upon failure of the ODMCS, discharge of effluent into the sea via the ODMCS must stop, and an entry must be made in the Oil Record Book.

At the time of ODMCS failure, the port State of destination, the Classification Society and this Administration must be immediately notified via fax, email or telephone. The vessel’s owners/operators should also be notified at this time and immediate measures taken to have the ODMCS repaired by a qualified service engineer.

Source: RMI