BUNKER SAMPLINGSampling methods Before any bunkering begins, the supplier or its representative barge master and the ships personnel must agree several important points relating to the sampling process, including location of sample point sampling method volume of samples to be taken number of samples to be taken sample sealing arrangements authorised signatories custody of bunker samples. Determination of the sample point position and the type of sampling equipment to be used should be agreed prior to the start of bunkering, and this should form part of bunkering procedures. Clause 18 of MARPOL annex VI requires that a bunker delivery note (see Chapter 9) must also be accompanied by a representative sample of fuel oil. The MARPOL sample should be taken at the ships receiving manifold. It is recommended that shipowners also take their own commercial samples at the ships receiving manifold, which is also the custody transfer point. The shipowner has three principal sampling options install a manual spot-sampling device install a manual in-line continuous drip sampler install an automatic continuous drip sampler which can be either set up to give a flow- proportional sample or a time-proportional sample. Taking a sample by continuous drip at the receiving vessels manifold has long been recognised as being the most representative sample of the fuel supplied. An automatic or manual continuous drip sampling method is therefore recommended. The volume of the representative sample should be agreed prior to the start of bunkering and should be sufficient to provide an adequate volume for both commercial and statutory MARPOL sample requirements. When bunkering has been completed, the sample is taken from the receiving container, typically a 5 l container, and divided into sample bottles to fulfil commercial and mandatory sampling requirements. In the past, a shipowner would typically divide the continuous drip sample into three or more samples, with one being retained on board, one being given to the bunker supplier and the third being sent for testing. Now however, with the requirement for a MARPOL sample, most prudent shipowners split the continuous drip sample into at least four samples so, if there is a quality dispute, they can test one of the samples retained on board without causing problems (the MARPOL sample cannot be used for this purpose). If bunkering in Singapore, the Singapore Standard for Bunkering requires five samples to be taken if the vessel is on a fuel quality testing programme (or four if it is not). As mentioned previously, authorised representatives from the ship, barge or shore and, if appointed, the independent bunker surveyor should agree the location and sampling device and then witness the sample being taken and transferred from the receiving container to individual sample bottles. It is of utmost importance that the bulk sample is thoroughly mixed before it is poured into sub-sample bottles and that each sample bottle is only filled a little at a time. If this is not done, the sub-samples will have different quality characteristics and this will cause confusion when the sub-samples are tested. Shipowners must be able to demonstrate the source of any samples and how they were obtained to show that they fully represent the fuel oil loaded. Shipowners should routinely take samples of all fuel oil loaded it is particularly difficult to gather such evidence retrospectively. Routine sampling and collection of accurate and appropriate records will also provide evidence that the ship and its crew have regularly adopted industry best practice. In the event of problematic fuel oil being loaded or fuel oil problems becoming apparent when engines are running, it may be necessary to undertake post- bunkering sampling. This usually requires sampling from three different levels in the tanks. Any fuel oil sampling should be done in a steady and methodical manner and the sample bottles should be clearly labelled, sealed and preserved. All samples should be treated with care if they are to provide the evidence bunker quality disputes require