What caused Finlandia Seaways’ exploding engine?

When a catastrophic engine breakdown aboard a cargo vessel resulted in parts from inside the crankcase flying across the engine room, investigators discovered it started with the failure of a single component.

On 16 April 2018, the Lithuanian registered ro-ro cargo vessel Finlandia Seaways was 11nm off Lowestoft, England, on a routine passage from Zeebrugge, Belgium, to Rosyth, Scotland, when it suffered a main engine failure so severe it caused serious structural damage to the engine and ignited a fire in the engine room.

The ship’s third engineer, on duty in the engine room, suffered serious smoke-related lung, kidney and eye injuries.

The third engineer had started his hourly inspection round of the engine and machinery spaces at 2000 that evening. As he entered the purifier room, he heard loud metallic knocking sounds coming from inside the engine room. Looking into the engine room, he saw smoke rising from the main engine as the noise and vibration levels began to rapidly increase.

Flashpoint

Sensing danger, he ran back into the purifier room and crouched behind one of the purifiers. Almost immediately, there was a loud bang and a huge flash of flames. The ship blacked out. Within seconds the emergency generator cut in and the emergency lighting came on, but thick, acrid, black smoke now filled all the engine compartments, reducing the third engineer’s visibility to zero.

Realising his nearest escape route would take him past the engine at cylinder head level he decided to use the secondary escape route at the aft end of the engine room. He took a deep breath and left the purifier room. Stepping into the cloak of dense black smoke, he ducked below the main engine exhaust gas trunking and ran aft past the two auxiliary generators.

The Finlandia Seaways more than a year after the incident (Credit: Shutterstock)

Traumatic escape

The escape route led him to the first of three ladders, but he struggled to get beyond the ladder platform guardrail safety chains, falling back down the first ladder three times, losing his torch in the process. He eventually escaped through the funnel casing weather-tight door onto the upper vehicle deck, where he collapsed, gasping for breath, and struggling to see properly.

A fracture of a connecting rod small end led to the sudden failure of the main engine.

Within 20 minutes of the start of the incident, the crew sealed the engine room, activated the carbon dioxide fixed fire-fighting system and extinguished the fire. The third engineer was taken by HM Coastguard helicopter to hospital for medical care, where he made a successful recovery.

Connecting rod under scrutiny

Accident investigators from the UK’s Marine Accident Investigation Branch (MAIB) identified that a fracture of a connecting rod small end led to the sudden failure of the main engine.

They also found that the method used to replace the connecting rod small end piston-pin bearing bushes by the vessel’s maintenance support contractor had introduced stress raisers that significantly increased the likelihood of crack initiation and fatigue failure.

Other factors that contributed to the engine failure included: maintenance management standards; lack of appreciation of the importance of following the engine manufacturer’s instructions for removing and refitting piston pin bearing bushes; and external oversight of the engine maintenance process.

Accident report conclusions

1. The fire was the consequence of a sudden major engine component failure, which led to the ejection of heavy engine parts from the crankcase and release of hot oil vapours into the engine room
2. The catastrophic engine failure was caused by a connecting rod small end that was found to have suffered a fatigue fracture
3. The introduction of notches, probably caused during the bush removal process, introduced stress raisers into the small end, increased the likelihood of fatigue crack initiation, and therefore fatigue failure
4. Poor overhaul practices probably caused the small end failure
5. Recommended procedures for overhauling the connecting rod small ends had not been followed and the small ends had been damaged during the piston pin bush removal and fitting process.
6. Seven of the 11 intact small ends removed from the engine were found to have notch damage on the mating surface with the bush, resulting from the use of a disc cutter to remove the bushes
7. The conrods were not overhauled in accordance with written procedures, and maintenance was not properly recorded
8. There was a lack of appreciation of the potential consequences of the stress raisers introduced during overhaul of the connecting rod small ends, and the damage was viewed as inconsequential when compared with the mass of metal that made up the small end
9. The main engine connecting rods were class survey items, but the classification society, LR, was not informed of the damage caused to the small ends during overhaul, or that connecting rods had accumulated more running hours than recommended by the engine manufacturer.

Read the full MAIB Accident Report.

Dennis O’Neill is a journalist specialising in maritime and regular contributor to Marine Professional.