Industry Insight: DNVPS on Understanding the Importance of Bunker Quantity Surveys

Sunil Nair is Operations Manager at DNV Petroleum Services

Bunkering operation involves different activities which includes quantity determination, drawing representative samples and subsequent analysis of the sample, documentation and safety assessment.

Millions of dollars are lost every year through disputes over bunker quality or quantity. With increased and fluctuating bunker costs it is more important than ever to avoid such disputes.

During a custody transfer of bunkers, the quantity delivered(bunker tanker out-turn) is usually based on the difference between the ROB(Remaining on board) in the bunker tanker prior to supply and the ROB remaining in the bunker tanker after supply.

The quantity received by the vessel (vessel out-turn) is similarly calculated on the basis of the difference between the ROB in the vessel after supply and the ROB in the vessel before supply.

The industry usually considers a bunker tanker's out-turn to be more accurate than the vessel's due to its smaller size, regular shape and configuration.  However, differences between vessel and bunker tanker out-turn are more often due to other factors.

Properly Monitoring the Bunkering Operation

During bunkering operations vessel staff are usually busy with other activities such as receiving lube oil, stores, carrying out machinery routines and do not have enough crew and time to monitor the bunkering operation properly.

Even if the vessel staff boards the bunker tanker to witness the bunker tanker measurements, the vessel staff are not familiar with the correct sampling procedure and the tricks-of-the-trade which can lead to an inflated supply quantity. When a professional surveyor is appointed, he can act as the extended eyes and ears of the customer.

Though quantity differences cannot be eliminated, a surveyor's work and documentation onsite increases the credibility of any quality and quantity claims.

Fuel sampling and analysis is essential for verification of the quality of the fuel received during bunkering to reduce or minimize the risk of claims arising or breakdown of machinery. Engaging a competent surveyor ensures correct sampling as well. One ppm equates to one litre in a 1000 tonne delivery which underscores the importance of sampling.  "The results are only as good as the sample received/collected".

A non-representative sample will obviously result in analysis with misleading information which affects the performance of ship's engines or damage to engines, and in a worst case scenario, endangering the safety of the ship. Hence the importance of drawing representative samples cannot be overemphasized.

With the experience gained from carrying out more than 85,000 bunker quantity surveys globally) since 1987 , DNV Petroleum Services (DNVPS) surveyors have helped customers to mitigate numerous quality and quantity disputes.