Piston Ring Breakage, Liner wear and Fuel Valve Failure – Consequences of Using Off-Specification Bunkers.



Ship Type: Mid-sized Bulk Carrier.
Location: Singapore Anchorage (Bunkering).
Engine: Daihatsu 6DK32, 4 Stroke Diesel engine.


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 Vessel bunkered IFO RMG 380 cSt fuel in accordance with charterparty clause. Due to commercial pressure and in an attempt to save on agency charges, the fuel sample was not sent ashore for analysis.

Speed Read – The Incident:

  1. Soon after leaving port, the engineers started using the new bunkers. They experienced abnormal sludge generation in the purifier.
  2. The amount of water and sludge removed by the purifier filled the sludge tanks fast.
  3. Main engine and diesel generator exhaust temperatures started to fluctuate.
  4. After 3 to 4 hours of new fuel usage, turbochargers started to surge and the engine speed was reduced.
  5. In order to prevent any power failure, the diesel generators were switched to diesel oil.
  6. The engine crew switched the fuel consumption to other double bottom tank – which yielded the same result.
  7. The purifiers required cleaning every 4 hours.
  8. The Engine speed was reduced such that a voyage of 16 days extended to 25 days to reach the next port.
  9. Main engine fuel valves and fuel pumps suffered severe damage which required complete overhaul.



  1. The owner decided to de-bunker and load fresh bunkers.
  2. During the vessel’s stay in port, various repairs were carried out to the main engine.
  • All Pistons were dismantled, overhauled and piston rings replaced.
  • One of the cylinder liners was cracked and has to be replaced.
  • The turbocharger nozzle ring was found completely choked with deposits.
  • Settling and service tanks were completely drained and bottom residues removed with shore assistance.



  1. Several fuel samples were taken during the vessel’s port stay and sent ashore for analysis. The test results revealed that the fuel was off-specification for water %, Sediment and MCR (Carbon).


Lesson Learned:

  1. The crew has to ensure that there is sufficient quantity of tested fuel oil reserve on board for consumption to cover the time delay involved in sending the newly bunkered fuel for analysis.
  2. The crew has to take sufficient representative bunker samples and send them immediately for shore analysis. Commercial pressures and ‘cost-cutting’ should not impair necessary shipboard good engineering practice.
  3. The test results from the lab should be known before using the new bunkers so that necessary precautions can be taken.

Source: GARD


    • Dear Capt. Esinduy,

      Thanks for your comments. Based on the above case, as a first measure, it is recommended to test the fuel against the ordered specifications. This will ensure any abnormality is adequately and properly dealt with.
      Testing of a representative fuel sample is essential and reports published by Viswa Lab will ensure that the ship staffs are warned so that remedial measures can be taken in good time.

      best regards
      MFAME Editor

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