Bunker survey
A bunker survey measures fuel: either how much is on board at a given moment, for on-hire, off-hire or a dispute, or how much a barge actually delivered to the ship. Both come down to careful soundings and correct conversion from volume to weight.
Two kinds of bunker survey
Quantity on board (ROB). The surveyor sounds every fuel and diesel tank, including settling and service tanks, takes temperatures, and converts the volumes to metric tons using the tank tables, the density from the latest bunker delivery note and a volume correction factor for temperature. This is the figure used at on-hire and off-hire.
Bunker delivery. When a barge supplies fuel, the surveyor sounds the receiving ship's tanks before and after, and usually the barge's tanks too. The difference is compared with the quantity on the bunker delivery note (BDN). Samples are drawn at the manifold during delivery, sealed and signed by both sides.
Corrections that matter
- Trim and list. Tank tables assume a level ship; soundings are corrected for the actual trim and list.
- Temperature. Fuel expands when warm. Volumes are reduced to the standard temperature before converting to weight.
- Density. The density on the BDN is used for the delivered fuel; a laboratory result can change the weight later.
Common causes of short deliveries
Entrained air (fuel that foams and reads higher than it is, sometimes called "cappuccino bunkers"), unmeasured fuel left in the barge's lines, wrong temperature, and soundings taken before the fuel has settled. A surveyor who sounds the barge before and after, checks the temperature himself and watches the delivery throughout catches most of them.
Where it happens in Turkey
Bunker deliveries are common at the Istanbul anchorages, in the Sea of Marmara, at Aliaga, Mersin and Iskenderun. Quantity surveys for on-hire and off-hire are usually done together with the hold condition survey.
Finding a surveyor
Choose the port on Portiva to see every authorized company there. To get quotes, send one request and we pass it to companies working in that port. Survey companies abroad looking for a local surveyor to attend on their behalf can use the attending surveyor request.