09/06/2015
Bunkering Survey
1. Understanding the Fuel Density & Weight Relationship
Marine fuel is always sold by weight (mass) and delivered by volume. Hence for this reason bunker receipts must always be signed "For Volume Only" and adding the words "weight to be determined after testing of the representative sample".
Never sign for weight if uncertain about the density.
What many bunker surveyors do not realise is that the density given in the supplier's Bunker Delivery Note (BDN) may not be true and thus the weight determined by calculation should be considered as the 'preliminary' weight of the fuel transferred to the vessel.
The actual weight is only determined after the density is verified by an independent fuel testing authority and then factored into the final recalculation of the actual weight of the fuel delivered onboard.
That is why we always stress the importance of accurately obtaining bunker samples both onboard the vessel and the barge.
Once the samples are dispatched to the vessel's chosen independent fuel testing laboratory we request the copy of the Fuel Test Reports so that revised bunker survey report can be sent to the client.
This procedure assists our clients in avoiding commercial losses.
Key Notes
• If the density of fuel cannot be verified onboard or independently verified at the time of bunkering, the BDN should be signed only for 'volume' and not for weight
• Remember whenever in doubt or have concerns always issue a letter of protest
2. Understanding the Fuel Temperature & Volume Relationship
The barge will often try to under-declare the temperature during the opening gauge and over- declare during the closing.
This malpractice is quite common in day-to-day bunkering and therefore we always ask the ship officers responsible for bunkering operations to be extra vigilant and check the temperatures of all bunker tanks during the opening gauge and thereafter periodically check and record the temperature of the fuel as it is pumped onboard.
The temperatures should be checked both at the barge and the ship's manifold.
If temperature gauges are provided it would be prudent to take photographs where permissible.
Key Notes:
• Always check and record the temperatures of the fuel tanks before and after and periodically during the bunkering operation
• Carry own infra-red laser temperature gun as a part of your equipment
• Remember whenever in doubt or have concerns always issue a letter of protest
3. Bunker Fuel Temperature
Accurate temperature recording is crucial when detecting bunker fuel concealment because the same mass of bunker fuel will record a slightly different volume at different temperatures.
Verify the temperature on the surface of the sounding tape just before it is being pulled out (this may not be very accurate but will give a general idea of the average tank temperatures).
In case of unusual high temperatures reported by the chief engineer, attach a manual thermometer to the tape bobs to ascertain the exact temperature.
Investing in a good digital thermometer may be worthwhile. These can be dipped directly into the tanks through the sounding pipe.
Note the body temperature of fuel oil transfer pumps before and after the soundings/measurements to eliminate any transfer of fuel oil and / or re-inspecting engine room tanks after completing the soundings.
For this reason it is advisable to start the soundings of the tanks located on the deck and working your way to the tanks in the engine room.
4. Bunker Fuel Concealment (giấu giếm ) Through Trim and List
When trying to detect bunker fuel concealment, it is important to note the trim and list of a vessel.
The perfect time for bunker quantity measurement is when no cargo and ballast operations are taking place and when the vessel is on even keel with no list.
However, during real-world bunkering operations this is not always practical.
As such it is important to check for list and trim accurately both before and after the soundings.
Take an average trim/list and always use the corrected trim for calculations.
5. Tank Soundings to Detect Bunker Fuel Concealment
Verify the condition of the sounding tape and be aware of any deliberate altering of sounding tapes and using the wrong size of bobs.
Always use own sounding tape and a ruler to report exact sounding or ullage especially if it is below the 20 cm mark.
Note down the reference heights / gauge heights of each tank in a note book and check the same against reference height noted by physical measurement of the tanks.
The reference heights will differ if some foul play is involved like blocking the bottom of the sounding pipes with bobs later to be fished out.
In cases like these investigate further and take the entire missing length as "full sounding."
Pay particular attention to 'millimetre' soundings especially when the tanks are full and taking ullages as small errors will have a big impact of the total bunker quantity.
6. Tampering with Gauging Equipment
Always verify the condition of the sounding tape. Sounding tapes could be tampered with in many ways:
1. Deliberate altering of sounding tapes and using wrong size of bobs
2. Sounding bobs from tapes that have been switched over
3. Cutting the tape and re-joining resulting in non-lineartape
Key Notes:
• Check for calibration certificate for the gauging equipment in use
• Use a ruler to ascertain the precise sounding/ullage when below the 20 cm mark
• Use own sounding / ullage tapes
• Pay particular attention to 'millimeter' soundings especially when the tanks are full and taking ullages as small errors will have a big impact on the total bunker quantity.
• Remember whenever in doubt or have concerns always issue a letter of protest
7. Inflated (phồng lên) / Deflated Tank Volumes
The level of oil on the tape / bob should be clearly identifiable and the same colour and viscosity as the rest of the oil in the tank.
Soundings can be inflated during opening gauging by pouring diesel oil into the sounding pipe just before gauging.
Another method of inflating the sounding is high pressure compressed air being injected directly into the sounding pipe, pressurizing the pipe and thus causing the level of oil to rise giving a higher reading without even frothing or creating bubbles.
This would be done en-route to the vessel just before delivery.
The reverse is also true - that is the soundings can be deflated during closing gauging by pouring copious amount of paint thinner into the sounding pipe just before gauging.
The thinner washes off the oil level marking on the sounding tape to indicate less oil.
Key Notes:
• Always check the level of fuel on the sounding tape and if in doubt re-gauge the tank
• Remember whenever in doubt or have concerns always issue a letter of protest
8. Concealed Fuel in Bunker Tanks
Verify the number and location of all bunker tanks onboard including overflow tank; sludge tank etc., ensuring it corresponds with the tank capacity diagram.
Note: Refer to supplements to Marpol I/VI Certificates. This will indicate the exact number and capacities of sludge tank, drain tank, residue tank, waste oil tank, bilge tank etc.
A surveyor might come across some tanks as being declared empty.
We have heard all sorts of excuses like: The tank is not in use as it contains only sludge or the heating coils have been damaged and the tank emptied out and not in use (check paper trail to find out if the operators have been informed of this or any repair work scheduled for dry dock, check log books etc.)
In any case investigate further by opening manhole covers for tanks that have been declared empty or containing sludge or other reasons.
9. Unpumpable Fuel, Zero Dip Volume Application
In an event of a short delivery be wary that empty tanks may not be empty even with zero dip and that substantial pumpable may exist.
Verify the tanks claimed to be empty - don't take the supplier's word for it.
Zero Dip Volume Application Principle
The bunker surveyor or the vessel representative should notify the barge representative that the zero dip volume of the tank(s) shall be included in the bunker tanker calculations.
The condition shall deemed to apply when the closing gauge would indicate no oil cut whereas the visual inspection of the bunker tanker cargo tank indicate free flowing oil at the aft of the tank.
To avoid zero dip volume application, sufficient bunkers should be retained in cargo tanks such that it touches all four sides of the tank.
To apply zero dip correction, it is assumed that the tank is rectangular where the sounding is not constrained by a sounding pipe – i.e. sounding should be taken in an "open sounding" position (from the hatch) where the sounding tape bob is free to travel with the trim of the barge and not restricted by the sounding pipe.
However, if the tape is used inside a sounding pipe this correction would be invalid.
Liquid cargo should only be trim and/or list corrected if the liquid is in contact with all bulkheads.
When the liquid is not in contact with all bulkheads, a wedge correction should be applied.
*Cut - The oil level on the tape or bob or the water level marking on a tape or bob coated with water indicating paste. "Taking a cut" is taking a measurement of the oil or water level.
Key Notes:
• Do not assume any tanks to be empty even when reaching stripping level
• Check tank calibration tables to verify the unpumable
• Apply correct list / trim corrections during calculations
• Remember whenever in doubt or have concerns always issue a letter of protest
10. Quantity Measurements by Flow Meter Only
The barge may claim that the soundings and ullage ports have been sealed by customs, or seized, or some other reasons, and therefore force the vessel to go by the volumetric flow meter only.
Remember that this may be just the first sign of an unscrupulous (không chu đáo) barge Master, and as such, be wary of other tricks of trade.
Key Notes:
• Never agree and go by the flow meter only fuel delivery
• Remember whenever in doubt or have concerns always issue a letter of protest
11. Flow meter / Pipe work Tampering
Bunker barges fitted with a flow meter should be checked for proper functioning by sighting a valid calibration certificate and ensuring the seal is intact.
There may also be unauthorised piping (by-pass lines) fitted to the flow meter running into the pump suction side and thus this un-authorised contraption (trái ngược) will register the throughput of fuel twice through the flow meter.
Key Notes:
• Verify flow meter seal is intact
• Verify validity of the calibration certificate and that it is for the same type flow meter
• Look out for any suspicious by-pass lines running after the flow meter
• Consult the barge piping diagram if in doubt
• Remember whenever in doubt or have concerns always issue a letter of protest
12. Inter-tank Transfers - Gravitating of Fuel
During opening gauge the fuel could be transferred from high level to a low level (or empty / slack tank) by gravity.
For example a barge may have four tanks 1P/1S, 2P/2S, 3P/3S and 4P/4S.
The opening gauge starts from say aft tanks 4P/4S.
While the gauging is underway, the tank level of 4P/4S could be easily dropped under gravity to a slack or empty tank forward say 1P/1S.
Thus essentially the same fuel quantity is measured twice.
This method is still in use and if not detected the barge can claim that full quantity was delivered to the vessel but the vessel will have a substantial shortfall.
Once the bunkering has commenced it is too late to do anything and it will be virtually impossible to trace the 'missing' fuel.
A thorough investigation will be needed to determine the exact stock control quantity and full disclosure from the supplier which can take many months/years of legal action and still the matter may not be resolved.
Key Notes:
• The only effective way of dealing with this dubious practice is re-sounding the first tanks before bunkering commences
• Remember whenever in doubt or have concerns always issue a letter of protest
13. Fuel Delivered with High Water Content
Traces of water in bunker fuel are normally very low at about 0.1-0.2% by volume.
ISO 8217:2010 Fuel Standards for ‘Marine Residual Fuels’ gives the maximum allowable water content to be 0.5 % v/v.
Water can originate from number of sources like heating coil damage causing leakages and tank condensation; however deliberate injection cannot be ruled out.
In case large quantity is found then a letter of protest should be issued immediately.
However, the exact quantity of water can only be determined after the settlement phase where the water would have settled down at the bottom of the bunker tank.
Key Notes:
• High water content causes other issues like removal costs to ashore if the OWS (Oily Water Separator) onboard is not able to filter it out and also reduces the fuel’s specific energy
• Fuel samples provided by the barge may not have any traces of water as the samples may have been taken prior to bunkering and mixing of water. Always ensure that the fuel samples are collected during bunkering and not before or after. For these reasons never sign labels in advance or sign for samples of unknown origin. Samples should only be signed for those actually witnessed.
• Use of water-finding paste on the sounding tape is good for distillate fuels only and does not work with residual fuels. Even incorrect type of ‘water-detecting’ paste could be used.
• On-site testing should be done for water-in-oil test. It may be not viable for the ship operators to invest in high end equipment for such purposes but as a minimum the vessel should be able to test a bunker representative fuel sample for water, test for density and compatibility.
• Remember whenever in doubt or have concerns always issue a letter of protest.
14. Pumping / Mixing Slops into Bunkers
Though we seldom come across this now, introducing slops and thus contaminants into the fuel delivery will reduce the actual fuel amount and also can create engine problems down the line.
Unfortunately this cannot be detected until the representative fuel samples have been tested by an independent fuel testing facility.
Key Notes:
• Always witness and collect samples by continuous drip method i.e. the sample to be drawn continuously throughout the bunkering delivery period
• It should be a practice onboard to isolate the fuel delivered to separate tanks and not to be consumed until such time the fuel testing report gives a clean bill of health.
• Fuel contamination amongst other things can create problems with the fuel injection system and exhaust valves with costly repairs.
• Remember whenever in doubt or have concerns always issue a letter of protest.
15. Identifying Cappuccino Bunkers
What Are Cappuccino Bunkers?
Cappuccino effect essentially may be described as frothing/bubbling (bọt) effect caused by compressed air blown through the delivery hose. The aerated bunkers when sounded will give the impression that the fuel is delivered as ordered. In fact after sometime when the entrapped air in suspension settles out of the fuel oil the oil level drops and a short fall is discovered. In large bunker deliveries this could be considerable with huge financial implications.
The Cappuccino effect still remains one of the most common and widely used 'mal-practices' in the bunkering industry to-date.
Despite lots of articles and loss prevention bulletins being issued by various P&I Clubs, we are still seeing lot of vessel's falling victim to this ill-practice.
Often our expertise is called upon at the next port of call when the vessel just five days into her voyage after stemming bunkers would discover a sudden "disappearance" of 30-40 MT overnight.
It is then too late for us or anyone to do anything!
The short article that follows focuses only on "cappuccino bunker effect" giving the reader a better understanding and grasp of the subject matter.
What is the Cappuccino Effect?
Cappuccino effect essentially may be described as frothing/bubbling effect caused by compressed air blown through the delivery hose.
We have often been asked why the flow meter cannot detect the air being introduced in the system and compensate accordingly. Well, most flow meters in use today are of either the wrong type or the wrong size. In other words are not technologically advanced. All the standard flow meters will only measure the volume of throughput and not the actual mass of fuel being delivered. As a result when is air introduced into the system, which is essentially 'small air bubbles' - the flow meter will register it as volume.
However, there are flow meters out in the market which are capable of measuring the true quantity (mass) of the fuel delivered. One such meter is the 'Coriolis Mass Meter' - it has been in existence for quite some time now and only getting better. Coriolis meters take direct mass flow measurements using the Coriolis Effect (a deflection of moving objects when they are viewed in a rotating reference frame. Coriolis meters are less sensitive to pressure, temperature, viscosity, and density changes, allowing them to measure liquids, slurries and gases accurately without the need for compensation. These meters having no moving parts require little maintenance however, the initial cost and line modifications is usually a deterrent (ngăn cản) for many ship operators for not installing it.
Precautions against Cappuccino Bunkers
Before Fuel Transfer - At the time of opening gauge fuel oil should be observed from ullage hatches for any foam on the surface of the bunkers. Foam may also be detected on the ullage tape. If there is no foam then the oil level on the tape should appear distinct with no entrained bubbles. If by observation of the tape and the surface of the fuel you suspect entrained air then obtain a sample of the fuel by lowering a weighted bottle into the tank. Pour the sample into a clean glass jar and observe carefully for signs of foam or bubbles.
If these observations show entrained air the Chief Engineer should not allow the bunkering to start and notify the Owners / Charterers immediately. The barge Master should be issued with a letter of protest. If the barge Master decides to disconnect from the ship and go to another location then the agent should immediately inform the port authority and try to establish where the barge has gone. All relevant times and facts should be recorded in the deck log book.
During Fuel Transfer - If the Chief Engineer has not observed any entrained air during the initial barge survey it is still possible that air can be introduced to the barge tanks or the delivery line during the pumping period for example by introducing air into the system by crack opening the suction valve of an empty bunker tank while pumping from other tanks. Hence it is important for the Chief Engineers to continue gauging the ship's receiving tanks while the bunkering is in progress as air bubbles would be readily seen on the sounding tape.
The Singapore Bunkering Procedure SS 600 prohibits the use of compressed air from bottles or compressors during the pumping period or during stripping and line clearing. It should be confirmed with the barge Master that he will follow this procedure
(Reference SS600 paragraphs 1.12.10/11/12/13).
Stripping of barge tanks can also introduce air and stripping should only be performed at the end of the delivery for a short period of time.
The barge Master must agree to inform the Chief Engineer when he intends to start stripping and when it has been completed.
Ship's crew and surveyor need to be alert during bunkering and check for the following signs:
• Bunker hose jerking (giật) or whipping (quất) around.
• Gurgling (ríu rít) sound when standing in vicinity (lân cận , gần) of bunker manifold.
• Fluctuations of pressure indication on manifold pressure gauge.
• Unusual noises from the bunker barge
After Fuel Transfer - It is also possible to introduce air into the delivery line during blowing through at high pressure. Therefore it is imperative that the barge informs the ship before and after blowing through is completed so that the ship crew can be extra vigilant (cẩn thận) during this period.
The ship's bunker manifold valve should be checked shut before gauging of the vessel's tanks.
Identifying Cappuccino Bunkers
• Signs of froth/foam on the surface of the fuel in the barge tanks during opening gauge
• Excessive bubbles on the sounding tape prior to, during and after bunkering
• Bunker hose jerking or whipping around
• Slow delivery rates then what has been agreed
• Gurgling sound in vicinity of bunker manifold
• Fluctuations of pressure on manifold pressure gauge.
• Unusual noises from the bunker barge
Note that hose jerking or evidence of sporadic (rời rạc) bubbles superf
16. Falsifying Documentation
Falsifying documentation onboard is one of the techniques used to conceal bunker fuel.
Questionable Tank Sounding (Calibration) Tables
Verify that the sounding / ullage tables are approved by the Class (Class Certified – with a seal).
Having more than one set of sounding books is not uncommon and having the tables modified to the supplier’s advantage is always a possibility.
Inserted pages, corrections, different print/paper type are all indications of tampering (giả mạo).
Sometimes the barge may have a new calibration table (with the old one being obsolete).
This could be following modification of the tanks internal structure during a dry dock repair or simply because the original calibration tables would have been incorrect.
Always find out the reason for new calibration table and making sure it’s Class Certified.
The same could be said for the list / trim correction tables which could be easily modified, again to the supplier’s advantage.
Key Notes:
• Look for Class Approved calibration tables with a seal
• Remember whenever in doubt or have concerns always issue a letter of protest
Incorrect Fuel Densities and Missing BDN Records
Fuel densities given by the Chief Engineer should be verified against Fuel Laboratory Analysis Reports for the most recent bunker stem and if not readily available then densities stated in the BDN (Bunker Delivery Note) should be used.
Since BDN must be retained on board for 3 years from the date of fuel supply and should be readily available for inspection by port state control and relevant authorities (because non- compliance with fuel oil sulphur limits could lead to fines / detention of the vessel) as such there is no excuse for not maintaining a file for previous and current BDNs.
Overstating Fuel Consumption
Verify fuel consumptions for last 30 days or as required from the engine's log book / noon reports / deck log abstracts. Example engine over consumption could be shown due to alleged heavy weather during the voyage or boiler over consumption shown even when the vessel would have been idle at anchorage for significant period of time in hot weather. These are all tell-tale signs of fuel misappropriation.
Oil Record Book (ORB)
ORB should be scrutinized (xem xét kỹ lưỡng) for last sludge / bilge transfer operations; retention of oil residues (sludge); identity and capacities of tanks; records of collection and disposal oil residue to shore facility etc. This will give an idea of the vessel's sludge and waste oil management systems. On many occasions concealed bunkers have been found in waste tanks transferred via an unauthorized connection like a rubber hose!
17. Double Losses for Operators from Undeclared Fuel
On many occasions we have come across situations where the receiving vessel will be as much as involved as the supplier in dubious bunkering practices.
Often we have found that the vessel would under-declare fuel quantity which is then either sold back to the barge supplier or simply kept hidden on the vessel until an opportunity comes along to profit from this.
Ultimately, it's the operator who is affected – who can actually suffer the loss twice.
Contributing factors for the loss:
• Too much reliance on the vessel's staff.
• No bunker stem audits are conducted which involves investigating detective work carried out by independent third party surveying firms.
• Ignoring non-nominating (non-receiving) tanks to be included in the overall tank measurements during stem operations.
• Most shipping companies will engage the services of an independent surveyor to protect their interest in case of a large discrepancy in the final figures between the barge and the vessel; however, how many companies actually give clear instructions to the attending surveyor to measure all non-nominated tanks (non-receiving tanks)? Or how many surveying firms actually carry out the measurements diligently? Failing to do so leaves the operator vulnerable.
18. Magic Pipes, Concealed Bunkers, and Bunker Investigating Surveys
At the present market rate, bunker cost is one of the largest operating expense incurred in a TC voyage. With such high costs involved, it becomes imperative for the charterers to know the exact bunker quantity onboard at the time of supplying bunkers.
Bunker Investigating Surveys
Bunker investigating surveys are carried out by marine surveyors on behalf of the charterers to find concealed (hidden) bunker fuel onboard.
To find concealed fuel someone qualified has to go on board the vessel and get their hands dirty. In order to prevent fuel losses, experienced surveyors offer impartial, independent quantity measurement inspection services for marine fuels, issuing detailed bunker survey reports to confirm fuel delivery and report any bunker fuel shortages.
How Bunker Fuel is Concealed?
There are many ways to conceal fuel on a vessel - some of the examples are:
• Short bunker delivery
• Hidden compartments
• Use of 'magic pipes'
• Altered sounding pipe lengths
• Non-class approved and / or altered sounding tables
• Sounding tapes not properly calibrated
• Doctored fuel gauges and so on….
What is a "Magic Pipe"?
Magic pipe is a terminology used when finding conceal bunkers. If used properly - to an untrained eye - it can be hard to detect and thus making bunker fuel disappear just like "magic."
These magic pipes are fabricated onboard by marine engineers and designed to fit tightly inside the actual sounding pipe. The bottom end of the magic pipe is closed and the pipe pushed through the fuel to the bottom of the tank. During sounding, the tank thus appears empty or gives false soundings.
Note "magic pipe" is also the term used to bypass the OWS (Oily Water Separator) connection in order to dump oil overboard. Unlike the use of magic pipe for bunker concealment, use of magic pipes to bypass the OWS is a criminal offence and heavy fines and penalties may be imposed and / or imprisonment.
19. Dealing with Bunker Disputes
In case of the event of a short fuel delivery, remember that time is of the essence as any post- bunkering investigation is many times futile (vô ích) and inconclusive (không đi đến kết quả).
However, the following minimum steps are recommended to safeguard owners/charterers interest:
• Immediately notify the parties concerned and appoint an independent surveyor if not already done so and do not disconnect hoses.
• Re-do the entire gauging, check and re-check both pre and post bunkering calculations making sure the list/trim corrections have been correctly applied.
• Verify correct temperatures and densities have been used.
• Issue letter of protest for each incident and have it acknowledged by the barge (note the barge Master will probably refuse to acknowledge such letters).
• Write up a detailed statement of facts leading to the short delivery.
• Preserve any evidence e.g. if you suspect froth on the surface of the fuel / too many bubbles on the sounding tape then taking photographs would be prudent.
• A success of a claim will largely depend on the nature and the quality of evidence gathered at the time the supply is made. If there is detailed contemporaneous (đồng thời) written evidence, the ship operator will be in a much stronger position in case of subsequent litigations.
• Further, it may be necessary for full disclosure of the supplier's stock movement reports to ensure that the original supplied quantity tallied with the quantity at the time of opening gauge.
• Another tactic we have seen is "pilot onboard" – this may seem like a stalemate and to the supplier's advantage (delaying the vessel's departure it never a good thing) but with careful handling of the situation the agent should be advised beforehand to postpone the pilot boarding thus giving the vessel sufficient time to resolve / deal with the dispute.
• The barge outturn figure (delivered fuel quantity) will be recorded on the BDN for invoice purposes. In case of a short fuel delivery a note of protest must be issued and the same reflected in the Oil Record Book (ORB) and do not sign the BDN as presented but sign only for the soundings and ship's volume.
CONCLUSION:
1) Remember whenever in doubt or have concerns always issue a letter of protest.
2) In doubt of number and location of tanks : Refer to supplements to Marpol I/VI Certificates. This will indicate the exact number and capacities of sludge tank, drain tank, residue tank, waste oil tank, bilge tank etc.
3) In doubt of sludge / bilge tanks :
Oil Record Book (ORB) should be scrutinized (xem xét kỹ lưỡng) for last sludge / bilge transfer operations; retention of oil residues (sludge); identity and capacities of tanks; records of collection and disposal oil residue to shore facility etc. This will give an idea of the vessel's sludge and waste oil management systems. On many occasions concealed bunkers have been found in waste tanks transferred via an unauthorized connection like a rubber hose!
4) In doubt of densities stated:
Densities stated in the BDN (Bunker Delivery Note) should be used.
Since BDN must be retained on board for 3 years from the date of fuel supply and should be readily available for inspection by port state control and relevant authorities (because non- compliance with fuel oil sulphur limits could lead to fines / detention of the vessel) as such there is no excuse for not maintaining a file for previous and current BDNs.
