Bunkering Operations: Precautions, Checklists, Calculations & Corrections Explained
An actual bunkering operation is carried out with bunker checklists. In this article, emphasis is made on the checklists, safety precautions, SOPEP locker and SOPEP equipment, temperature and density correction to calculate the quantity of oil bunkered. The formula for calculation has been included
Bunkering Oil
Earlier we learned about the bunkering and what is means. Now we will study the process of actual bunkering operations and the practical details of the process of bunkering oil. All types of ships needs fuel oil, lube oil, etc. and hence it is important for everyone to understand the actual process of bunkering, so here we go.
Pre-bunkering preparations.
The most important aspect of bunkering operation are the "checklists", which form a part of company's safety management system (SMS) and I.S.M.,eliminating the possibility and negligence of human and other operational errors. The pre-bunkering checklist must be followed in-consultation with the Chief Engineer (C/E), as he is the person-in-charge for the bunkering operation. Before bunkering, usually it is 4th engineering officer, taking "soundings" of bunker tanks and calculates the volume of fuel oil available in every fuel oil tank of the ship. Then a Bunker-plan is made to plan the distribution of total quantity of bunker fuel oil.
Bunker Procurement
Ordering of Bunker oil:
The ship Managers (superintendents) monitor the performance of a fleet of ships. For example, on owning a car, we tend to keep a check on its fuel consumption widely called as "mileage." It is the distance travelled by the vehicle for a unit volume of fuel used. In the same way, as the ship consumes humungous quantity of fuel, whose costs are forming the major part of ship's operation. Managers tend to keep a check on it. This is measured in terms of specific fuel oil consumption of the main propulsion engine.
Upon knowing the fuel oil consumption for a day and the next voyage plan, the quantity of fuel oil required is calculated and compared with the available bunker tank capacity. A requisition is placed through the C/E and Master of the vessel to the Managers. The requisition is processed and evaluated for the quality and quantity of fuel to be supplied for the particular ship. Planning is done for the delivery of bunker at a particular port where the oil is available at a comparitive lesser cost. On taking all these aspects into consideration, the Managers, deliver bunker to the vessel. Upon receiving the bunker, a sample collected during bunkering operation is sent for lab analysis to confirm the delivered oil meets the required standard for the safe and efficient operation of the auxiliary engines & main propulsion engine.
Pre-Bunker Checklist
1. State of adjacent waters noticed
2. Vessel properly secured to dock
3. Check suppliers product corresponds to ordered product
4. Agree quantity to be supplied
5. Check valves open
6. Day tanks full and supply valves closed
7. Warning signs in position e.g. No Smoking
8. SOPEP plan available
9. Clean up material in place
10. Oil Boom in place
11. Foam fire extinguisher placed at bunker station
12. Alfa Laval and transfer pumps off
13. Fuel tank supply valves open
14. Agree stop/start signals between vessel and barge/truck
15. Bravo flag flying/red light showing
16. Agree pumping/transfer rate
17. Agree emergency shut down procedure
18. Specification sheet received
19. Check hose and couplings are secure and in good order
20. Fuel nozzle and hose secured to vessel
21. Check barge/truck meters Reading:
22. Check on board meters Reading:
23. Bunker Valve open
24. Unused manifold connections blanked off
25. Master informed
26. Signal pumping to commence
The above checklist has to be completely filled religiously by both the ship & barge personnel. Please move on to the next page by clicking below
Image Credits
Automated Bunker Procurement Flowchart: Calsoft Enterprise Solutions, USA
SOPEP equipments
At the bunker manifold and wherever necessary, as per the ships SOPEP plan, the SOPEP equipments should be kept in immediate readiness in order to avoid oil spill/pollution during bunkering operation.
SOPEP- Shipboard Oil Pollution Emergency Plan.
The SOPEP Locker must have minimum of the below specified items:
1. absorbent roll
2. absorbent pads
3. absorbent granules
4. absorbent materials
5. brooms
6. shovels
7. mops
8. scoops
9. empty receptacles (200 ltrs capacity)
10. portable air driven pumps
11. oil boom
12. oil spill dispersants.
These items must be stowed in an easily accessible locker, clearly marked, and is to be brought on deck ready for immediate use, prior to all oil transfer operations.
During Bunkering Procedures - Checklist
1. Witness taking and sealing of 2 representative product samples
2. Monitor fuel connections for leaks fuel flow and control tank levels
3. Change over of tanks whenever necessary.
4. Checking the rate at which bunkers are received.
5. Checking the tightness/slackness of mooring ropes.
6. Checking trim/list of the bunker barge & the ship.
7. Continuous monitoring/look outs for the vessel's position(when at anchor).
During bunkering, the above checklist must be filled up and continuous monitoring of the above secified items are required till the bunkering operation is complete.
After Bunkering Procedures
On completion of the bunkering operations, with the ship-barge co-ordination, the line should be blown with air to make sure the line is not filled with oil. The after-bunker checklist is followed.
After Bunker Checklist
1. Bunker Valve closed
2. Disconnect hose (drain before disconnecting)
3. Check barge/truck meter Reading:
4. Check ships meter Reading:
5. Sign Bunker Delivery Receipt BDR No.:(Bunker Delivery Report/Note).
6. Retain BDR with product sample
7. SOPEP plan returned to bridge
8. Clean up gear stowed / Oil boom returned
9. Bravo Flag/Red light stowed/switched off
10. Remove and pack away warning/safety signs
11. Foam fire extinguisher placed back in correct location
12. Complete Oil Record Book
13. Master informed of completion
14. Confirm in Oil Record Book Bunkering checklist completed
Quantity Calculation & Temperature-Density Correction:
After bunkering of various fuel oil tanks, the quantity in each bunkered tank must be calculated to cross-check whether the received quantity of oil matches the requisition. For calculating the quantity, "sounding" of the tanks which are "bunkered" must be taken. The "Density" of the fuel oil supplied vary from place to place. It also varies with the temperature. As a thumb rule, the density of fuel oil decreases with increase in temperature. So, when the oil is supplied at a higher temperature, then the volume of oil supplied is less than what is supplied at lesser temperature.
Oil Temperature ----------------------------Density ------------------------------- Volume Of Oil Supplied
Increases--------------------------------------Decreases------------------------------------Lesser
Decreases--------------------------------- ---Increases -------------------------------------More
Also the formula which is generally used for temperature-density correction is as follows:
MT = (Temperature Corrected density * Actual Sounded Volume).
Temperature Corrected Density can be calculated with the under-mentioned fomula:
Temperature corrected Density = Density of Fuel Oil @ 15 degree Celsius * [1- {(t1-15) * 0.00064}]
where
t1 stands for temperature of oil in bunker tanks in degree celcius,
0.00064 is the correction factor,
volume of oil in m^3 (actual sounded volume), is obtained from the sounding table.
Safeties
General Safeties During Bunkering:
SOPEP locker,
Emergency shut-down arrangements,
Bunker line over-flow arrangements to overflow tank with audible & visual alarm,
Relief valve in the bunker line,
Containment trays.
Consistent & Continuous look outs.
Conclusion:
Thus bunkering operation is directly related to "MARPOL" annexes, i.e annex 1 and annex 6. When oil is spilled it causes marine pollution under annex 1. When the bunkered oil doesn't meet certain specifications, it causes pollution of air which comes under annex 6.