bunkering operation

Bunkering Operation: Precaution, Procedures & Checklist

Last Updated on June 24, 2018 by Amit Abhishek

Ships require different grades of oil for their day to day operation. The delivery of oil supplies to the ship in the form of fuel and lube oil is refereed to as bunkering. And the process of transferring oil supplies to the ship is termed as bunkering operation. Conventionally bunkering is done in ports but with modern techniques and heavy traffic; bunkering can now be done at sea under normal weather condition.

In the olden days when coal was prevalent as fuel for producing steam for propulsion of locomotive and steamship, the container within which the coal was stored were called Bunker. Since originally coal was the fuel for the ship, the term bunker has became synonymy with fuel therefore term bunker / bunker fuel is simply marine fuel oil used in ships.

A bunker fuel is the residual fuel oil left over from the refining process of crude oil. It is consumed by both large land based plants and large ships for its propulsion and auxiliary engines. Bunker fuel are relatively cheaper then the crude oils from which it is derived; and so plays a prominent role in reducing overall cost of commercial shipping.

Marine fuels are thick, heavy, difficult to store, require special technique to transport with mandatory heating requirements before use. Actually it is a simple bargain between the daily running cost and the cost of maintenance. Bunkering is a complex process requiring team-work, planing and proper housekeeping, but It is to be noted that there is no universal standard for bunkering procedure.

Bunkering Operation At Sea

Currently a big portion of commercial ships bunker at sea while others still follow or forced to follow the conventional method for bunkering at port. Dedicated bunkering pipelines, berths and tankers are used at port for the bunkering operation. While bunkering barges provide bunkering facility in many points along the major sea routes.

Irrespective of the place and mode of bunkering; proper procedures must be followed from calculating the volume of fuel needed to the last check point in the checklist to follow. Although risk associated and bunkering procedures are almost similar; there are both advantages and disadvantages in bunkering at sea.


  • No longer needed to turn the ship off course for bunkering.
  • It saves lots of time that takes to go to a particular port for the purpose none other than bunkering.
  • No need to wait in those long lines to berth and bunker.
  • Quick and easy bunkering procedure at sea.
  • Less traffic at port avoiding unnecessary ships for bunkering increasing the waiting process at loading or discharging.
  • No need to pay those port charges at sea.


  • Difficulty maintaining the position of both the ship and the bunker barge with respect to each other.
  • The whole process at sea is not much safer in comparison with bunkering at port.
  • Not available at all places across the world.
  • Less and late support in event of some emergency in respect to pots where more and quick help is available.
  • High risks of oil pollution due to collisions, unwanted spill and accidents.
  • Different arrangement are needed for different types of ship to supply oil at sea.

Types of Bunkering in Ship at Sea

Different methods are used at sea for the purpose of bunkering. While some are slow but safer others offers a fast transfer rate at little more risks and planning. These two most common types of bunkering procedure followed by merchant ships are:

1 ) Ship To Ship Bunkering

A ship to ship bunkering bunkering is a process of transferring fuel oil in which two adjacent ship positioned alongside to each other supply fuel oil from one to another. It is the most common type of bunkering procedure at sea; where one ship acts as a terminal while the other moors.

In ship to ship bunkering operation the ship that supplies the fuel irrespective of its size is called mother ship while the one that receives is called daughter vessel. The hose pipes from mother ship ( mostly barge ) is transfered to the other vessel with the help of a crane. Once connected pups on the mother ship will force the fuel to the other ship via these hoses.

At start the pumping rate is kept low to ensure its going to the right tank or tanks. Once confirmed the pump rate is increased to maximum limit discussed to complete the process as soon as possible.

2 ) Stern Line Bunkering

It is the most easy but risky way of transferring fuel from one ship to another during bad weather. It is the only way a ship can bunker at UN-steady sea; due to very high risk and chance of damage to ships due to collision with one another. In stern line bunkering both ships approach each other slowly.

Once they are at a distance of 100-150 meters apart towing lines are secured. Both vessel will maneuver at a speed of 2 nautical miles during the whole process. Long hose pipes of 200 m are transfered from one ship to another. During calm weather the process is easy and effective; while during UN-steady sea it become the only but risky bunkering operation.

Risk’s Associated With Bunker Fuel

1 ) Oil Spill

Oil spills are one of the most serious problem associated with bunkering. Any accidental oil spill during the process leads to heavy fine on the company and damage to the environment. The major source of oil spill are either collision between the receiving and supplying vessel followed by spill due to overflow.

2 ) Disputes on The Sulphur Content

Fuel oil available all over the world contains different amount of sulphur content and oil grade depending upon the crude and refining process. Above all there can be dispute with the supplier over the actual sulphur content, sampling procedure, volume and flow rate. All above difficulties can be be easily avoided following good bunkering practice.

3) Health Risk

Marine fuel is preheated to a certain temperature before use or pumping. There is a increased risk of skin burn after contact with associated machinery and pipelines. If accidentally came in contact with the oil one can have various skin problems. The oils are also a source of health hazard as they contain not just carcinogenic substance; but produce / release hydrogen sulphides which is quite dangerous to health if accidentally inhaled during the bunkering operation.

4 ) Damage To The Engine

Marine fuel of low quality can severely damage the parts of an engine. These fuel will lead to poor combustion and overheating which results into damage of piston and piston rings. Incompatible fuels if mixed with one other can cause great difficulties such as filter problem, damage to injectors and emulsification of the fuel mixture.

Bunkering Procedure

A bunkering operation includes from deciding the grade of oil ( DMA / DMB / DMX / DMC / RME24 / RMG35 / RMF25 etc or in simple words heavy fuel oil, diesel oil and gas oil ) to the securing SOPEP Equipments and sampling. It is a complex set of process that can be classified into following simple categories:

1 ) Ordering

The bunkering process starts not from the transfer of fuel but right with the chief engineer calculating the mount of fuel needed for the voyage. He make sure the oil to be produced not only approved / recommended by the engine manufacturer; but also specified by the charter party taking into consideration of ISO regulation 8217.

The amount of normal and low sulphur grade fuel is calculated based on the planned route of voyage. Marpol Annex VI ( 6 ) states that the bunker fuel must not contain any chemical or additives; which can adversely affects the safety and working of a ship, contribute / leads to air pollution and is harmful to the crew.

It is the duty of the chief engineer to ensure that the oil being ordered follows regulation 14 and 18 of Marpol Annex VI ( 6 ). Once all the calculations are done. The chief engineer must consult and agreed upon with the master on the quality and quantity of fuel considering possibility of bad weather.

Then the order must be sent to the head office with the time of delivery, Quantity, type of fuel and delivery location.

2 ) Preparation

The key for a safe and successful bunkering operation is planning! Plans are made during the pre-bunkering meeting about the details of the process, safety measures, communication medium and role of each individuals. Such meetings are done way before the real bunkering procedure with all individuals involved in the process to identify risks, discuss plans and agreed upon a fixed set of operating procedure.

Tanks and pipelines used to be prepared before the actual transfer of the bunker fuel. Watch schedule be put at the manifold at deck to monitor  accidental oil spill and at the control room. local rules and the time of bunkering must be discussed with all during the pre-bunkering meeting.

It must be ensured before the actual transfer of bunker fuel; that all the associated individuals are adequately prepared and been allocated to their designated jobs. One individual from the team must be given single most important job to provide safe access / passage to and from the barge.

Proper discussion must be done during the meeting to avoid accidents and damage to life and ship. Whole crew must be aware and trained to use the SOPEP equipments in need. Special emphasis must be given at personal protection and effective communication between the ship and the barge during the meeting.

Read Further information about SOPEP

3 ) Pre-Bunkering

The ship must be ready for any fuel transfer before the actual bunkering process. All associated tanks and pipes should be lined up, sounded and prepared. No smoke and warning signs be placed, ship personnel to be briefed, code B Red flag be hosted or red light be turned on during night.

Both the bunker station and its trays must be cleaned and deck scupper be plugged. close all necessary overboard valves and place oil absorbing material at different strategic / key locations. Check all the pipes for tank ventilation and sounding for being open and closed respectively. Ensure that the high level alarms on each tank is functional.

Check for the weight and length of the hose with condition of its coupling for damage. Discuss the bunkering plan and transfer process with the barge and agreed upon the signaling procedure, sampling process, and response in time of emergency. A ship crew from the engine side be present at the barge to take soundings during the start and end of the transfer process.

Establish proper communication link in between the operating personnel at ship and the barge. Agree upon the final quantity to be transfered, flow rate, measuring unit ( S.I or C.G.S or Local ), sampling process ( whether the samples taken at barge and ship be exchanged or not? ) and possible arrangement for emergency stop.

needle valve bunkering operation

4 ) Bunkering

The actual transfer of fuel takes place with the slow pumping of fuel. All associated valves position and tanks are verified for correct order with any leaks in the hose connection. Pressure gauge and tank levels must be closely monitored and associated valves be operated with low flow rate during changing over tanks.

A ship crew from the engine is present on the barge to take samples and sounding during the start and end of the transfer process. Samples must be taken at both barge and ship right at the start of the bunkering operation. Generally the samples taken on barge and ship are exchanged for safety purposes.

Total four samples are taken in total with one for the ship, other for the laboratory for study and report, one for the supplier and the last for compliance with the MARPOL regulations. MARPOL samples are also kept at ship to show them to the authorities at port or on demand.

The quantity and flow rate of fuel oil is monitored throughout the process from the control room and pressure gauge and flow meter manually at different position. Once the required amount of fuel oil is being transfered; all hose connections are to be disconnected, drained and manifold sealed.

It must be taken care of that there is sufficient ullage in the last tank filled for draining pipelines or hose connections. Samples are to be sealed and labeled properly in the presence of the ship crew. At last a signed bunker delivery note is is handed over by the supplier with a copy kept at barge and one given to the ship. All tanks need to be resounded for the procedure to be complete.

Bunker Delivery Note

A bunker delivery note or “BDN” in short is a document that works as a record for fuel transfer between the two vessels / Port and ship. The document is signed by the master of the barge or port authority and chief engineer of the receiving ship. Copies of the document is kept by both the supplier and ship for further use and compliance with regulations for next three years.

Under MARPOL regulation 18 appendix V ( 5 ) a bunker delivery note must contain; the name and IMO number of the ship, the port or sea location, date, grade and type of oil, its quantity, sulphur content, density of fuel with the address and name of the supplier. the document also certify that the fuel is in compliance with MARPOL Annex VI ( 6 ) regulation 14 { 1 , a } and 18 { 1 } once signed by the supplier.Bunkering Operation samples

Precautions To Be Taken While Bunkering Operation

  1. Wear complete PPE ( Personal Protective Equipment ) including gloves, hard hat with chin strip on and safety harness.
  2. All Operating personnel must know of any dangerous characteristic of fuel as stated in MSDS ( Material safety Data Sheet ).
  3. All deck openings and scupper must be plugged or closed.
  4. Different grades of fuel oil must never be mixed together.
  5. All un-required flange must be blanked and tank soundings be taken at regular interval.
  6. Place dip trays under the hose pipe lines at strategic positions.
  7. Flow rate must be slow during the start of the bunkering procedure to avoid unwanted mixing, spill or overflow.
  8. SOPEP Kit be available to use.
  9. Oil absorbing material be available at different positions.
  10. Make sure the vent lines for tanks are clear.
  11. Internal tank overflow arrangement must be there and checked prior to the process.
  12. proper communication link must be there in between the ship and barge personnel.
  13. The operator must test or ask for the hydrocarbon content in the tank.
  14. Temperature of bunker transfer must be regulated upon with the supplier.
  15. Care must be taken while changing over from one tank to another.
  16. care must be taking while obtaining maximum loading volume for each tank.
  17. Follow the proper checklist for bunkering operation.
  18. All firefighting system and equipment must be ready for any emergency throughout the bunkering operation.
  19. Radars on board to be switched off and VHF to be used on low power.
  20. No smoking signs to be placed and strictly followed.

Bunkering Checklist

  • Measures the content / volume of oil in each tank.
  • Prepare tanks for the bunkering operation.
  • Vessel to be securely docked or bunker barge be moored successfully.
  • All Pipelines be lined up.
  • Code B Red flag be hosted.
  • Warning signs be placed.
  • The final amount of bunker fuel to be transferred is decided.
  • SOPEP plan is discussed and available.
  • SOPEP equipment be placed for use at strategic positions.
  • Start / Stop signal is decided between the vessels.
  • Communication medium between the ship’s is decided / agreed upon.
  • Maximum pumping rate be decided / agreed upon.
  • Hose connections be checked for any leakage.
  • Unused manifold connection to be blanked off.
  • Bunkering operation be start at a minimum pumping rate.
  • Rate of fuel transfer must be temporary reduced during the changeover from one tank to another.
  • Supply pressure must be monitored at all times.
  • Samples are to be taken.
  • Suppliers must be informed in advance about the stopping of the pumping.
  • Drain hose pipes after the completion of operation.
  • Blank off all closed manifold connections.
  • Take sounding of all associated tanks.
  • Take BDN.
  • Verify the information with that given on BDN and record in the oil record book.
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2 thoughts on “Bunkering Operation: Precaution, Procedures & Checklist”

  1. Captain Subrata Kumar Bose

    Good presentation .The process of testing the bunker a and contents of BDN should be included .

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