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Marine Loss Prevention Circular No

 

Marine Loss Prevention Circular No. 01-00

SHIP TYPE:

Panamax Bulk Carrier

YEAR OF BUILD:

1981

EVENT: Main Engine Damage Due to Ignition Delay

Course of Events
In a Gulf of Mexico port, the vessel received heavy fuel oil IFO 180 according to ISO category RME 25 with a density of 989,6 kg/m3 and a viscosity of 172 Cst. The bunker receipt information and the following DNVPS analysis coincide with respect to these parameters.

Based on the density and viscosity information, the ignition qualities of this fuel (CCAI) were calculated to 860 which is acceptable for slow speed engines. The vessel is equipped with a 16-cylinder medium speed main engine of European design, and this fuel is on the limit of where operational problems could be expected for medium speed engines. As a result, the chief engineer on board and the ship management office were informed by DNVPS that precautions should be taken to ensure satisfactory combustion.

The chief engineer on board and the ship manager ashore did not pay any attention to the fuel analysis. They did not considered the specific recommendations issued by the engine maker or DNVPS’s precautions for operating the main engine with fuel with inferior ignition characteristics. To compound the problem, the vessel was sent to areas for trading including days with river passage with variable loads on the main engine. This made it difficult to maintain maximum combustion temperature and thus made it virtually impossible to follow the operational recommendations.

The delayed combustion resulted in increased combustion pressure, combustion close to the cylinder walls and the consequential failure of the lubrication of the pistons and liners.

Extent of the Damage
The result was a complete breakdown of all pistons, cylinder liners and cylinder heads with related parts. Due to lack of availability of spare parts onboard ship, only preliminary repairs were made. Thus, the voyage to the discharge port was made at reduced speed. Meanwhile, the company had to make arrangements at the discharge port to acquire spare parts and make preparation for final repairs. The vessel was taken off-hire upon arrival at the discharge port.

As a result the total cost to repair is approximately $530,000 USD and the total time off-hire is approximately 45 days.

Probable Cause
The ship manager and/or commercial operator of the vessel made the error in believing that a lower viscosity fuel (180 Cst) was of better quality than a high viscosity fuel (380 Cst). This is commonly seen when a fuel supplier lowers the viscosity by adding lighter components that may seriously alter the ignition characteristics.

The ship manager had arranged for sampling and analysis of fuel. However, the ship manager had not ensured that their chief engineers were provided with proper procedures and instructions to take the necessary precautions against damages that could be incurred by inferior quality fuel.

The result was that the vessel left the bunkering port with no preventive actions and precautions on how to deal with a situation with a fuel on board with inferior combustion characteristics.

Lessons to be Learned
The importance of fuel sampling and analysis is essential for verification of the quality of the fuel received on board. There is however little value in companies spending money on sampling and testing if shipboard engineers are not properly trained to understand the fuel quality analysis and provided with procedures and instructions on how to adjust the fuel equipment and engines accordingly.

Procedures and instructions should be established in the technical or operational departments on how to:

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establish requirements for fuel quality depending on the fuel treatment equipment and engines on board

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follow-up the vessels' bunkering schedules, ensure correct sampling and where to send samples for analysis

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ensure the engineers on board and technical staff ashore will understand the analysis and the limitations for their equipment, and

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in the event of having taken on fuel of inadequate quality, establish communication with the engine makers and fuel analysing company in order to provide proper instructions to the vessel.