Engine Failure and Fire on board a Ro-Ro Ferry

Summary

On 16 April 2018, catastrophic structural damage occurred in the engine of a ro-ro cargo vessel. The accident happened when the ship was 11 miles off the coast of UK, in the North Sea. The engine failure caused a fire in the engine room. The third engineer (3/E), who was on duty at that time, suffered serious injuries.

The cause of the accident was a fracture of a connecting rod in the main engine. Several major internal rotating components were thrown through the side of the crankcase into the engine room and there was a short but intense fire. Within 20 minutes, the crew conducted an emergency muster, sealed the engine room and used a CO₂ fixed fire extinguishing system to extinguish the fire.

The 3/E was evacuated by helicopter to hospital where he was treated for his injuries.

Accident Report:

1. Occurrence of the accident

At 15:45 the vessel departed Belgium for UK. The 3/E began his watch at 18:00. He monitored the engine control room (ECR) and undertook hourly inspection rounds of the engine room. At around 20:00 the 3/E left the ECR and started the hourly check of the engine room. Shortly after entering the purifier room, he heard loud metallic knocking sounds coming from the engine room. At the same time, the officer on watch (OOW) on the bridge felt powerful vibrations. The OOW immediately checked the propeller pitch angle and main engine speed gauges. The OOW saw that both gauges were fluctuating and immediately reduced the propeller pitch from 60% to 25%. Various engine warning lights appeared and the fuel consumption meter was also fluctuating and giving abnormal readings.

The 3/E opened the purifier room door and saw smoke rising from the port forward end of the main engine. He returned to the purifier room, fearful of the rapidly increasing noise and vibrations. He crouched behind one of the purifiers whereupon, at 20:03, there was a loud bang followed by flames flashing past the open purifier room door. The room filled with thick black smoke. The ship blacked out, but power was restored within seconds by the emergency generator and the emergency lighting came on. However, the engine room was filled with smoke and the 3/E had almost no visibility.

2. Emergency responses

a) Master

The Master was alerted by the strong vibrations and arrived on the bridge as the blackout occurred. The fire alarm system was activated and the bridge alarm panel indicated that all zones of the engine room were affected by the accident. The Master immediately took control of the situation and put the controllable pitch propeller to zero. The Master ordered the OOW to sound the general alarm and use the intercom to alert the crew. All crew members were instructed to go to their emergency muster stations. At about the same time, the chief officer (C/O) arrived on the bridge and reported smoke coming from the funnel.

b) Chief engineer

The chief engineer (C/E), who had also been alerted by the ship vibrations, was already reacting to the emergency. He had noticed that the main engine’s No. A5 cylinder exhaust gas temperature deviation alarm had activated on his cabin alarm panel. Initially, the C/E thought the cause may be a fuel system problem, but when he approached the engine room, the blackout occurred. The C/E went aft to the port side of the main vehicle deck, opened the engine room access door, and encountered significant smoke and heat. He shouted for the 3/E but there was no reply. Next, the C/E attempted to enter the ECR via the cargo control room, but again encountered smoke and heat. There was no sign of the 3/E. The C/E called the bridge from the steering gear space and reported the engine room fire to the Master. The C/E then operated the engine room fuel system quick closing valves and emergency stops from the control box adjacent to the ECR.

c) Third engineer

The 3/E realised that the nearest escape route from the purifying room would take him by the main engine at cylinder head level. He therefore decided to use the secondary escape route at the aft end of the engine room (Figure-1). He took a deep breath, exited the purifying room and, in the thick black smoke, went underneath the main engine exhaust gas trunking. He ran aft past the two auxiliary generators, finally arriving at the first of three vertical ladders that were the escape route. He managed to climb the ladders, albeit with much difficulty. At 20:13, the 3/E escaped from the engine room through the weathertight door in the funnel casing, reaching the upper vehicle deck.

Figure-1 Escape route of 3/E

d) CO₂ fire extinguishment

Once the 3/E was located, the fire vents were closed and the engine room fuel supply was isolated, the C/E advised the Master to release the engine room’s CO₂ fixed fire extinguishing system. The Captain ordered the 2/E to activate the system. The 2/E and 2/O went to the CO₂ remote release station on the forecastle deck and, at about 20:20, released the CO₂ into the engine room. Next, the 2/E went to the CO₂bottle room and confirmed that the control lever for the engine room had operated properly and that there was frost on the CO₂pipework. He also confirmed that the CO₂ supply line pressure gauge reading was about 20 bars and, a short time later, that the pressure had fallen to zero. Initially, the crew used their hands to monitor the engine room boundary temperatures. They subsequently used thermometers to measure and log temperatures periodically and recorded that the temperature was slowly decreasing.

e) Confirmation of extinguishment of the fire

Around 20:27, the Master gave the order to drop the starboard anchor, which held the ship with four shackles. At 20:37, the Master reported to the UK Coastguard that the fire situation had been stabilized.

The vessel was taken under tow to a port in UK where the Fire Brigade boarded the vessel to confirm that the fire was out.

3. Post-fire inspection

The accident severely damaged the structure and components of the main engine. The crankcase structure was ruptured on the port and starboard sides of cylinders five and six. In addition, the crankcase explosion relief valve doors and large sections of the crankcase casting were blown several meters across the floorplates.

A5’s connecting rod (Figure-2), the lower half of its piston and the crankshaft counterweight were ejected through the starboard side of the crankcase. B5’s connecting rod and its piston were also ejected from the crankcase and were found on the starboard deck plates (Figure-3).

Figure-2 A5 connecting rod

Figure-3 B5 parts ejected to starboard

In addition, The A5 and B5 pistons, cylinders, crankshaft and many other parts and structural components were destroyed.

Analysis

1. Sequence of events

The accident caused catastrophic damage to the main engine and ejected many heavy engine components from the crankcase into the engine room. A very hot mist of oil was released, which resulted in a fire that filled the engine room with thick black smoke. This section explains the causes of this incident and analyzes the factors that led to the fire.

The first indication of a problem on board was when the 3/E, who was in the purifier room, heard loud metallic knocking sounds. Furthermore, the OOW, Master, C/E and other crew members felt powerful vibrations throughout the ship. The first engine alarm to activate was the main engine crankcase oil mist – high alarm. Immediately afterwards, alarms sounded alerting to the high temperature of the number six main bearing and for a splash oil monitor failure. Within two seconds of the first alarm, the engine standby lubricating oil pump started. The engine automatically slowed (auto slow down) and, after 10 seconds, the engine room fire alarm sounded.

Based on the accounts from crew members and the sequence of alarms, the cause of the accident was clearly a sudden major engine component failure rather than the result of gradual wear and/or insufficient lubricating oil. This conclusion is supported by the loud mechanical knocking noises, automatic activation of the standby lubricating oil pump, the sequential failure of internal alarm sensors, and failure of the crankcase explosion relief valve doors to open prior to the ejection of rotating components into the engine room.

2. Identification of the component failure

The structural damage to the engine crankcase was restricted to units five and six, with internal components from the A5 and B5 cylinders ejected into the engine room. Consequently, the initial component failure must have occurred in either the A5 or B5 cylinder. The accident site damage inspection revealed that the upper half of the A5 piston had seized in its upper cylinder liner with its piston pin still in place. The lower liner was damaged and had fallen into the engine sump. It was therefore evident that the A5 connecting rod had failed at its small end eye.

Figure-4 Connecting rod (seen from the bow side) and fatigue fracture

3. Maintenance management

Routine maintenance of the main engine, a MAN12V 48/60, and major component overhauls were conducted in accordance with the ship’s Planned Maintenance System schedules. Most of the maintenance schedules were based on accumulated running hours set by MAN.

Minor routine maintenance was performed by the ship’s crew. The ship’s owner had a contract with a ship maintenance company, for major overhauls. This contract included inspections and, as needed, replacement of the connecting rod small end piston pin bushes.

Post-accident examinations and laboratory tests revealed that MAN’s guidance and recommended procedures were not followed when the connecting rod small ends were overhauled. The small ends had been damaged by a disc cutter or another tool during the piston pin bush removal and replacement process. Although the extent of the damage was clearly visible to the naked eye, the damage was either not identified during overhauls, or had been ignored.

Conclusions

The investigation by the UK Marine Accident Investigation Branch (MAIB) identified the following causes of this incident:

The incident was caused by a fracture of the A5 connecting rod small end eye, which led to a fatigue fracture.
Notches were most likely caused by the improper overhaul of the A5 small end eye.
When the connecting rod small ends were overhauled, the manufacturer’s guidance and recommended procedures were not followed. The small ends were damaged during the piston pin bush removal and fitting process, resulting in notches that increased stress and led to a fatigue crack.

Based on these findings, the operator of the vessel established and implemented the following preventive measures:

Inspections and replacements of all connecting rods on all sister vessels
Main engine overhauls of all five of the company’s vessels in accordance with service letters of manufacturers and other companies
An increase in the number of people in the preventive maintenance system support team
Implementation of a safety bulletin for ship crews
Review of the databases of subcontractors to confirm the suitable qualifications of those who perform main engine repair and maintenance work
Review the company’s Planned Maintenance System to be certain that all activities comply with the maintenance, repair and replacement guidance of manufacturers

The MAIB submitted the following recommendation to the owner:

Review and improve how the chief engineer’s conduct class-related equipment examinations as part of the Continuous Survey Machinery cycle to ensure that examinations are performed thoroughly and reported accurately.

Lessons learned from this accident

In this case an engine malfunction sparked a fire that resulted in an extremely serious accident. There are three key points to keep in mind concerning this incident.

1. Strictly adhere to maintenance procedures

The failure to follow the manufacturer’s guidance when performing work on the main engine was the direct cause of this accident. An improper procedure resulted in the failure of the engine’s connecting rod. All maintenance work conducted by a ship’s crew must strictly comply with the Planned Maintenance System. Furthermore, when subcontracting major work to a company with specialized skills, the ship’s owner (manager) and crew must hold discussions with the subcontractor to ensure that the work will be performed in accordance with procedures recommended by the manufacturer.

2. Emergency evacuation readiness

The engineer on duty near the main engine was not seriously injured because he was able to use a suitable escape route even though the engine room fire caused a blackout. As part of routine fire drills and ship evacuation drills, crew members should confirm evacuation routes and perform simulations of evacuation routes for fires in specific locations.

3. CO₂ fire extinguishing system

Among the various methods used on ships to fight fires, CO₂ is normally the last method used following the initial firefighting activities. Typically, it is not recommended to use CO₂more than 30 minutes after the start of a fire to stop the fire spreading.

The important steps below must be followed in order to use CO₂ for extinguishing a fire:

Close fire-resistant doors and ventilators
Confirm the presence and location of everyone on board
Release the CO₂
Use boundary cooling
Measure the temperature in the fire zone
Have specialists confirm that the fire is extinguished

Note: Keep the space where the CO₂ was released sealed until a specialist confirms that the fire is out. Allowing air to enter the space may enable the fire to reignite.

In this case CO₂ was released 20 minutes after the fire started and the fire was successfully extinguished. The crew deserve praise for this achievement, which is the result of the knowledge they had acquired through fire drills, training and other safety activities on this ship.

Reference

MAIB investigation report 2-2021:

https://assets.publishing.service.gov.uk/media/603ce1738fa8f5049da20b44/2021-.pdf

NB: Figures 1 to 4 are referred to in the above report