Hull and machinery incident - Consequences of using off-specification bunkers

Another example of the importance of sampling and testing bunkers.

Bunkering
A medium-sized bulk carrier was delivered HFO (heavy fuel oil) bunkers whilst at anchorage at a port in the Far East. Since the vessel was scheduled to sail to Europe, and due to the prevailing fuel prices, charterers decided to bunker the vessel to almost full capacity. The operation itself took several hours and was completed without problems. However, the vessel did not take its own fuel samples during the bunkering, but instead received two sealed samples from the barge operator. Both samples were signed by the vessel's chief engineer; however, neither of the samples was sent ashore for further analysis.

The fuel delivered was specified as 380cst -RMG 35, which was in accordance with the applicable charterparty.

Problems
Soon after leaving port, the engineers started using the new bunkers. Shortly thereafter, they experienced abnormal sludge generation in the purifier, which resulted in excessive water-sludge content in the settling and service tanks. A large amount of water and sludge was drained from these tanks. The amount of water and sludge also resulted in problems with the performance of the main engine, in the form of fluctuations in exhaust temperatures, as well as a rise in the scavenge temperatures of the various units. The main engine fuel pumps and fuel injection valves also sustained some damage.

 View of damaged cylinder liner.

View of damaged cylinder liner with piston fitted.

In order to prevent any power failure, the fuel consumption of the auxiliary engines was switched to diesel oil. The engine crew switched the fuel consumption to another double bottom tank, containing the newly bunkered HFO, but with the same result. Consequently, the engine crew had to consume the recently bunkered HFO for the propulsion machinery as nothing else was available and as a result the vessel had to reduce speed and slow steam to the next port, which was 12 days away. It took several days to reach the next port whilst maintaining reduced speed. They also had to stop several times each day to replace fuel valves, fuel pumps and to clean filters and change exhaust valves  dealing with turbocharger problems. The service and settling tanks were being drained almost continuously.

Repairs
The vessel finally arrived at the next port of call several days late. The owner decided to pump the off-specification bunker ashore and ordered new bunkers. During the vessel's stay in port, various repairs were carried out to the main engine. All pistons were dismantled and overhauled and piston rings were replaced. Several of the piston top rings were broken whilst one was badly worn. One of the cylinder liners was cracked and had to be replaced. The main engine fuel system and turbocharger had to be completely overhauled and the settling and service tanks had to be emptied and cleaned.

Several fuel samples were taken during the vessel's stay in port and sent ashore for testing, which revealed that the fuel was off- specification. The whole operation became very costly, time-consuming and caused delays to all involved.

Lesson learned
It is strongly recommended that:
- the crew ensure  there is sufficient quantity of tested reserve HFO on  board for consumption to cover the time delay involved in sending newly-bunkered representative samples for testing and receiving the laboratory test results.
- the crew take sufficient representative samples of bunkers received and send them ashore for testing.
- laboratory test results for newly received bunkers are known before consuming the bunkers.