Short answer: during a bunker survey, an independent surveyor appointed by the buyer checks the receiving vessel’s tanks before delivery, verifies the bunker tanker’s mass flow meter seals and readings, witnesses continuous sampling, records the final meter figure and the vessel’s own soundings, and reports any discrepancy before the bunker delivery note is closed.
In Singapore, bunker surveyors and bunker surveying companies must be licensed by the MPA. A survey does not change who is responsible for the delivery. It gives the buyer an independent, technically qualified witness on board.
Before the bunker tanker arrives
- Briefing: the surveyor receives the nomination: grades, specifications, quantities, tolerance and delivery window.
- Opening soundings: the surveyor measures or witnesses soundings of the receiving vessel’s bunker tanks, with temperatures, to establish the quantity already on board.
- Tank plan: the chief engineer’s tank allocation is reviewed so new fuel goes where planned and is not mixed with incompatible stock.
When the bunker tanker is alongside
- Meter checks: the surveyor checks that the mass flow meter system’s seals are intact and its verification is current, and records the opening totaliser reading.
- Documents: the bunker tanker’s delivery documents and product details are checked against the nomination.
- Sampling set-up: the continuous drip sampler at the receiving manifold is checked, and bottles are prepared.
- Safety: pre-delivery safety checks are completed by the vessel and the bunker tanker.
During the transfer
- The surveyor observes the delivery, notes start and stop times, flow rates and interruptions.
- Signs of air entrainment, unusual flow behaviour or line clearing with compressed air are recorded.
- Sampling is monitored to ensure it runs for the whole delivery.
After the transfer
- Meter figure: closing totaliser readings are recorded and the meter printout obtained.
- Closing soundings: the receiving vessel’s tanks are sounded again and a ship’s figure calculated.
- Samples: samples are divided, sealed, labelled and signed for, and seal numbers recorded.
- Documentation: the e-BDN is checked against the meter figure and specification details.
- Protest: if there is a discrepancy, the surveyor helps the vessel issue a letter of protest before signing off.
The survey report
The report records the figures from each source (meter, vessel soundings, BDN), the conditions during delivery, the sampling arrangement and seal numbers, and any irregularities. If a quantity claim follows, this report and the meter printout are the core evidence. See common bunker quantity disputes.
When to appoint a surveyor
- Large stems, where a small percentage difference is significant
- New or unfamiliar suppliers
- Charter party or owner requirements
- New fuel types, such as biofuel blends
- Any previous dispute with the supplier
The supplier should be told in advance that a surveyor will attend, so the surveyor has access to the meter and sampling equipment without delay.
Frequently asked questions
Who appoints the bunker surveyor?
Usually the buyer, directly or through its trader, broker or agent. The surveyor works for the party that appoints it and reports to that party.
Can a surveyor stop a delivery?
A surveyor observes and reports. Decisions to stop a delivery rest with the vessel and the bunker tanker, but a surveyor will advise if they see a safety or measurement problem.