Engine fault due to effect of low-sulphur fuel on injection control unit says report

Coking debris found in the cavity on the fuel oil side of the servo piston. Photo credit: TAIC
Coking debris found in the cavity on the fuel oil side of the servo piston due to low-sulphur fuel Photo credit: TAIC

A Transport Accident Investigation Commission (TAIC) report reveals that the Singapore-flagged ship Funing had been unable to generate full power because a fuel injector control unit (ICU) had suffered fuel leakage and become clogged with coking debris from the use of low-viscosity low-sulphur fuel.

On 5 July 2020, the log carrier Funing finished loading its cargo at the Port of Tauranga and began preparations for departure. At about 2200 the officer of the watch contacted the engineers and informed them that departure was planned for midnight. When the main engine was tested in the astern direction, the main engine fault log indicated there was a fuel injection quantity piston failure. The engineering team attempted to rectify the fault but were unable to before the vessel departed its berth at about 0018, when the fault reoccurred again on the main engine.

At 0024 the tugs were let go, and at 0027 the Port of Tauranga harbour pilot ordered full ahead. The vessel’s speed through the water was about 4.3 knots. By 0043 the vessel’s speed through the water was about 0 knots, and its speed over the ground was about the same as the ebbing tidal stream of 3.5 knots. The vessel was effectively drifting with the current and moving out of the channel. Shortly afterwards the vessel drifted over channel marker ‘B’ buoy and the buoy’s mooring chain became entangled in the Funing’s rudder and propeller.

Probable cause

– The engineers identified a fault with the main engine during pre-departure testing, but they did not confirm it was rectified before departure.
– Ineffective communication between the master and chief engineer meant the bridge team were not fully aware of the problem with the main engine, nor its implications in respect of vessel manoeuvrability.
– The main engine defect was not accounted for during the bridge team’s preparation for departure, and therefore the harbour pilot was also unaware of the defect.

Recommendations

After the investigation, TAIC recommended Wärtsilä to take further steps to help ensure users of its RT-Flex engines are fully aware of all the effects of the IMO sulphur cap and its operational effects on ICU performance, maintenance and lifetime service.

Lessons learned

The role that bridge resource management and engine room resource management play in respect of the safety of a vessel cannot be overstated. Good communication between departments is a core principle that may, had it been implemented on this occasion, have caused the master to reconsider the planned departure time.

Download the full report: TAIC Funing Report

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