bunker quantity dispute

“The Morning After Effect” – Bunker Quantity Dispute

It can be said with a degree of certainty, that when disputes arise over bunker quantity, any ‘post-delivery’ investigation on quantity shortages are often inconclusive especially if the shipboard personnel involved in bunkering operation have neglected the basic principles of safeguarding its owners/charterers’ rights in way of collecting and preserving evidence.

A success of any bunker dispute claim will largely depend on the detailed contemporaneous written evidence by the shipboard personnel at the time the supply is made.

To that end Constellation Marine services strongly recommend the use of a bunker quantity surveyor.
Considering the present bunker fuel prices, we opine “bunker stem survey” is necessary, to make sure that the quantities as mentioned on the Bunker Delivery Note (BDN) are true and correct and matching with quantity received by the ship.

However, there are many ship operators who leave the above procedure to the Chief Engineer to save on survey cost with the vessel often ending up with incorrect supplied quantity and a commercial loss of thousands of dollars for the operators.

Loss prevention during bunker stemming largely depends on the hands-on approach and practical experience of the bunker surveyors and Constellation Marine Services having in-depth experience is able to offer these ‘Bunker Stem Surveys’ to ship owners and charterers regionally.

The importance of this service cannot be over emphasized, and the following story will highlight this:
The owners and Chief engineer of a super Yatch located in Dubai dry docks made a call for an independent bunker sounding exercise to Constellation Marine services.

Upon attendance it was observed that the bunker delivery was already completed, a BDN was signed by the Chief Engineer on the agreed amount of 300 MT.

During the bunkering operations, no ship tank sounding was taken, the Chief Engineer relying on a sophisticated electronic tank gauge system located within the engine control room. On completion of bunkers, the Chief engineer signed off the BDN provided by the Supplier for the delivered quantity.

After a certain period, post 6 to 8 hours after completion of the bunker operation, the chief engineer decided to gauge his nominated tanks and discovered 34MT short supply.

Surveyors from constellation Marine were engaged thereafter for an independent sounding, and it came as no surprise that our attending surveyor discovered 36MT short supply and the reason.

The Chief engineer was now left exposed with no recourse to defend the short fall, having signed the BDN already. In short, he “was had” by the tricks of the supplier and was left nursing the typical “morning after” syndrome.
Constellation Marine Services over the years have carefully analyzed and assimilated the “tricks of the trade” employed by typical bunker suppliers and are in a very good position to offer advice, consultancy and loss prevention to its clients – shipowners and charterers and any party that are stemming bunkers.

The extent to which bunker suppliers will go to, and the knowledge and experience of Constellation Marine surveyors to counter this, is highlighted below. Trust this will assist potential owners and charterers to make the right choice for their bunker surveyor requirements


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 do not realize 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. 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.


In view of the several thousand tons of marine fuel sold and purchased each day, the high rate of thermal expansion of Marine fuels must be considered.

Suppliers, specially through bunker barges 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 its extremely important to check all bunker tanks during the opening gauge and thereafter periodically check and record the temperature of the fuel as it is pumped onboard.

Always check and record the temperatures of the fuel tanks before and after and periodically during bunkering operation

Remember whenever in doubt or have concerns always issue a letter of protest


So much has been mentioned about the cappuccino effect yet there is so little ordinary bunkers surveyor can do to find this out. At constellation marine services, our experienced bunker surveyors have a keen eye and ear to ascertain the this is being done.
Our surveyors can easily identify if the following signs are an indication of a cappuccino effect or otherwise:
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


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.

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.

Our bunker surveyors will 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 witnessed.


It is not uncommon for bunker supplier barges to transfer fuel cargo from a high-level tank to a low-level tank by gravity. Essentially what this achieves is a measurement of the same quantity of fuel 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.

Our bunker surveyors are aware of this practice and they will always re-gauge the tanks in the following sequence:
If the initial gauging was forward to aft, then after gauging the last aft tank; our surveyor will re-gauge all tanks from aft to forward. The readings must be the same.

As an additional precaution, our surveyor will re-gauge the first tank(s) used to transfer oil to the vessel to ensure the reading matches that taken during the initial gauging.

The only effective way of dealing with this dubious practice is re-sounding the tanks as above before bunkering commences. There is no other preventive measure available for this.


NEVER agree to go by the flow meter reading alone for fuel delivered quantity. Modern flow meters are extremely capable devices designed for an accurate measurement of what they are designed to measure, and highly difficult to tamper with BUT – There may also be unauthorized piping (by-pass lines) fitted to the flow meter running into the pump suction side and thus this unauthorized contraption will register the throughput of fuel twice through the flow meter.

Keep a bunker surveyor handy and on board in-spite of barges claims of a fully functional Flow Meter.


Having more than one set of sounding book 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. 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.

The same could be said for the list / trim correction tables which could be easily modified again to the supplier’s advantage.

Our attending surveyors have experience to call this out and will always be there to engage the barge supplier to provide ONLY class approved clean tables.


Our attending surveyors will NEVER TAKE THE SUPPLIER’S WORD FOR IT, EVER on a tank being empty. They will always verify that the tanks claimed to be empty are indeed empty.
Our bunker surveyor will notify the barge representative that the zero-dip volume of the tank(s) shall be included in the bunker tanker calculations.
Our bunker surveyors will insure liquid cargo can 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 will be applied.
The only way thus to ensure Empty Tank is indeed empty is
Do not assume any tanks to be empty even when reaching stripping level
Check tank calibration tables to verify the un-pumpable
Apply correct list / trim corrections during calculations


This is indeed a contention that is hard to digest by the vessels owners and operators. It is therefore extremely important for owners and charterers to employ bunker surveyors to ascertain the exact fuel quantity onboard prior stemming bunkers.

The malpractices during bunkering operations which we see and hear about are quite prevalent with bunker suppliers; but on many occasions we have come across situations where the receiving vessel will be as much involved as the supplier in these dubious 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.

To end, we request ship owner, charterers and any party stemming bunkers to make use of an independent bunker quantity surveyor, not just any but one that has the relevant experience, acumen and intelligence to call out and counter the “tricks of the trade” employed by bunker suppliers.

Do not thus fall for the morning after Syndrome.

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