Changing on-board bunkers safely

In a web alert, marine insurer Skuld has warned that challenges and risks arose when changing from one fuel to another on board. It said that it had handled many cases in which a new fuel was mixed with the fuel already in use, but proved incompatible.

Risk was minimized when the operation was carried out properly according to best practice. Skuld identified some of the challenges on-board a crew might face and provided guidelines to reduce the risks of possible engine and fuel-equipment damage.

Numerous bunker disputes over the years revealed that challenges and risks did not begin at the time of changeover on board. They might arise at the time of the request for fuel oil, so the risk management process for bunker changes should be considered in chronological order, from the moment of ordering to the time of consumption.

Fuel changeover was typically in one of two situations:

·       The vessel was consuming fuel oil or gas oil and needed to change to a new batch.

·       The vessel was consuming fuel oil but was approaching a Sulphur Emission Control Area (SECA or SEC area) and needed to change to low-sulphur gas oil.

The actual change-over procedure from fuel oil to gas oil was similar for every vessel, and engine manufacturers provided specific instructions on how to complete the process.

However. they might not have done so for changeovers from one batch of fuel to a fresh supply of the same type, whether Intermediate or Heavy Fuel Oil (IFO or HFO), Marine Diesel, or Gas Oil (MDO or MGO).

Skuld said that the following steps should be followed.

Order and ensure you receive the quality of fuel that is required by the engine’s manufacturer. Skuld said that it had seen several cases where the charterparty left too much room for interpretation. Quality was normally referred to in the standard specification ISO8217, with the year of the subject standard as an extension. The most recent standard was 2017, but was not yet commonly in use. Most often used were 2005, 2010, and 2012; the older years’ standards were most prevalent.

With five or more parties possibly involved in the ordering process from the time the request is made by the charterer or owner to the time it reaches the physical supplier, it was quite common for these divergent parties to apply different standards. In one case that came before Skuld the fuel originally ordered was ISO8217:2010, with some additional requirements, but the fuel delivered was ISO8217:2005, without the additional requirements.

An onboard inspection of the supplying barge should be made before receiving new fuel, including its void tanks, which must be dry. Another inspection should be carried out when bunkering is complete, especially in cases of difference between the quantity that the barge believes to have supplied and what the vessel claims to have received. The on-board sampling methodology used by the barge should be checked, since the chief engineer eventually signs for the fuel. On board the receiving vessel, a continuous drip sample should be taken from beginning to end of the delivery. It is best to invite the barge crew to witness the set-up of the sampler, and to monitor it during delivery.

After bunkering is complete, the continuous drip sample collected should be divided into four sample bottles, all properly labelled and sealed.

One should behanded over to the barge.

Another should be sent to the usually used laboratory.

The new fuel should not be used until the analysis results were known and indicated that the fuel was within specification. Skuld noted that this should be done as soon as possible, because suppliers normally had a time bar of 10 to 14 days, after which any claims are waived.

The standard rule on board was that mixing fuels was to be avoided. The new fuel had to be taken into empty bunker tanks.

Tanks should normally be cleaned every five years – sometimes more often – to prevent too much build-up of settled components, which could easily be disturbed during periods of bad weather. Skuld said that it had seen instances where the sludge on settling tank bottoms contained more than 10,000 ppm of aluminium and silicon. The sludge which collected in bunker tanks also needed to be collected and disposed of at regular, normally five-year, intervals.

Viscosity controllers, which adjust fuel viscosity upon its injection into the engine, also required attention. Not all IFO and HFO fuels had the same viscosity, even when they were the same grade.

In temperature control mode, actual fuel viscosity needed to be known to set the correct temperature. Skuld said that in several instances vessels had received fuel oil with a viscosity lower than 380 cSt at 50 degrees, and sometimes had received 180 cSt, when 380 cSt had been ordered but was not available.

Skuld said that it was grateful to BMT for contributing to the article.