BUNKERING NOTES
All the responsible officers should be familiar with all aspects of bunkering and the ship’s bunkering system, and one such officer should personally supervise the operation. He must be in close contact with the shore/barge especially with respect to stopping of bunkers in case of emergencies.
On arrival at bunker port delivery documents of the fuel supplier to be examined and compared with instructions of owner/charterer. Density, viscosity, sulphur content, etc. to be matched with ordered ones.
All valves should be checked and those not to be used, must be securely closed.
Oil absorbent materials should be easily available. Fire fighting appliances to be kept handy. Scuppers should be sealed.
Communication system should be checked between ship and shore.
All hose connections to be frequently checked.
Before bunkering sounding of the ullage at shore installation or barge to be taken and signed jointly.
If there is a flow meter fitted in bunker line, counter to be noted.
Ship tank soundings to be taken.
Overflow tank must be emptied and tank vent drip tray drains to be closed.
Bunkering should start at a minimum rate so that any problem may be detected early. Tanks should not be filled more than 90% capacity.
For final topping up of tanks, pumping rate must be minimum.
Special care to be taken while hose disconnection after completion of bunker.
Instruction to Personnel
Before any transfer of product is undertaken, the officer must confirm the following items, with the person in charge of barge/terminal bunkering. Each will sign the form to acknowledge.
Pumping data
Quantity and type of stock to be transferred
Initial transfer rate
Maximum transfer rate
Maximum transfer pressure
Anticipated stoppage time
The method of communication between barge/terminal and vessel has been established.
Except for emergencies, minimum stand by time for shutting down to be agreed
Hose condition
Are connection between barge and vessel/terminal properly secured
Are scupper plugs in place
A continuous deck watch to be kept by vessel and barge
In the event of an oil spill clear understanding for actions to be taken
All unused manifold connections are blanked off
Method of sampling to be agreed
Bunker Samples
It is imperative that representative bunker sample is collected in sealed bottles signed and dated by both chief engineer and the local supplier. Normally four bottles are collected. One for retaining onboard, one for fuel oil analysis, one for the supplier and one for MARPOL.
Immediately after taking bunker, a sealed sample must be sent by the chief engineer ashore, so that a proper analysis can be carried out. In the event of a genuine quality or quantity problem arising, it is imperative that the supplier is advised as soon as possible. The supplier may decline to accept the liability, if this is not done within a specified period. The period of notification should be mentioned clearly in supplier’s terms and conditions.
The sample must be representative of the total delivery, and ideally taken by the drip feed at the discharge side of the manifold, during the course of pumping process. Samples should not be taken at the start or on the completion of bunkering because then they will not be representative of the total tonnage loaded. Also samples should not be just from one tank of the barge.
HIGH DENSITY
Density is defined as the mass per unit volume and expressed in kg/m3 in SI units. This is one of the important bunker properties. Marine fuel oils have a linear density/temperature relationship, as opposed to water for example, and decreases with increasing temperature at a rate of about 0.66 kg/m3 per degree celsius rise.
Significance
Quantity calculation
Seperability of water and solids – to select the optimum size of gravity disc for purification
Specific energy calculation
Calculated Carbon Aromaticity Index (CCAI) – measures the ignition quality (increased index number causes an increase in ignition delay)
HIGH POUR POINT
The pour point is the lowest temperature at which a marine fuel can be handled without excessive amounts of wax crystals forming out of solution. At 3 degree C below pour point temperature, the fuel will become gel thereby preventing flow under its own weight. So more viscous fuels need to heated up to maintain their pumpability.
HIGH WATER CONTENT
Significance
Wet sludge
Corrosion (specially sea water)
Possible ignition interference
Displacement of fuel quantity
Specific energy calculation (heat loss)
Saline water in the emulsified state has a particular affinity for highly cracked fuels and heavy sludging can be experienced during purification. Water can cause cavitations in pump suction, corrosion and disturbed atomization during combustion, ignition retarded and cylinder liner lube oil film diluted. Water is separated by gravity separation in the fuel tanks and by centrifugal purification in purifiers.
BUNKER CALCULATION
TAKE THE ULLAGE OF THE TANK AS IT IS HEAVY OIL THE ULLAGE IS 2.99.mtr.ASK BRIDGE ABOUT TRIM SUPPOSE TRIM IS 0.8mtr.BY AFT,FROM SOUNDING TABLE TAKE THE TRIM CORRECTION . IF ULLAGE TRIM CORRECTION FOR 0.8mtr. is -2cm. NOW THE ULLAGE IS 2,97.mtr. THE VOLUME OF ULLAGE IS 105.529.m3 ,THIS IS OBSERVED VOLUME,
TAKE THE TEMPERATURE OF THE TANK THE TEMPERATURE IS 48°C.
AS THE BUNKER DELIVERY NOTE THE DENSITY OF THE BUNKER IS 988.KG/m3.AT 15°C.
FROM THE VOLUME CORRECTION TABLE WE CAN FIND OUT THE CORRECTION FACTOR FOR THE OIL FOR 988.KG/m3 DENSITY IS 0.9773.
TEMP.°C
DENSITY AT 15°C.KG/m3
CORRECTION FACTOR
48°C
988.KG/m3
0.9773
THERE FORE THE VOLUME OF OIL AT 15°C.WILL BE105.529 MULTIPLIED BY 0.9773 = 103.133.m3
THE DENSITY IS THE ABSOLUTE RELATION SHIP BETWEEN MASS AND VOLUME, NOT WEIGHT TO VOLUME.THE DENSITY IS THERE FORE "IN VACUO"
SO, MASS = DENSITY X VOLUME = 988.kg X 103.133 = 101895.89.kg = 101.896.M.T. THIS IS IN VACUO
DENSITY AT 15°C.KG/m3
FACTOR FOR CONVERTING WEIGHT IN VACUO TO WEIGHT IN AIR
975.7 to 1060.4
0.99895
SO WEIGHT OF THE BUNKER IN AIR = 101.896 X 0.99895 = 101.781.M.T.