On 1st March, 2016, the 2008 Maltese registered 10,744 dwt chemical/oil tanker ‘Askara’ left Kobe, Japan after completing her cargo discharge operations. She was bound for Hong Kong for bunkers.
In preparation for the bunkering operations and in order to avoid mixing the new bunker stem with the one already on board, the Chief Engineer instructed the Second Engineer to transfer all the fuel oil from port heavy fuel oil (HFO) storage tank to the starboard HFO tank.
The fuel oil transfer was carried out successfully as requested. However, towards the end of the transfer, the Second Engineer noticed that the low level alarm fitted on the port HFO storage tank did not activate. A manual sounding confirmed that the fuel oil had been transferred and that the level was well below 0.5 m - the level which should have triggered the low level alarm.
Suspecting a fault in the low level alarm switch, the Second Engineer instructed the Third Engineer to overhaul the alarm low level alarm switch on the port HFO storage tank in order to identify and rectify the fault. This task was discussed between the Third Engineer and the Chief Engineer and the necessary ‘Permit to ‘Work’ document was issued.
Just after 1700 (local time) on 5th March, 2016, after his engineering watch, the Third Engineer started to dismantle the low level alarm switch. This was a conventional float switch, fitted by means of four studs and its removal was a relatively simple task.
At about 1710, immediately after dismantling the low level alarm float switch, fuel oil escaped from the opening almost instantaneously . It was immediately evident that the tank from where the low level alarm switch had been removed contained a significant volume of fuel oil and there was enough static pressure for the leaking fuel oil to reach the main engine exhaust manifold.
The Third Engineer tried to mount the fuel oil low level alarm back to the tank in an attempt to stop the fuel oil leak. However, in view of the heavy flow and the high temperature of the fuel oil, he was unsuccessful. Soon after, as the fuel oil came into contact with the main engine’s exhaust manifold it ignited.
Shortly after, the fire alarm sounded around the vessel. One of the oilers, who was on duty in the engine room, tried to extinguish the fire by using one of the portable foam applicators. He did manage to extinguish the fire on the main engine, however, another fire developed in way of the turbocharger’s turbine side.
By 1713, the engine-room fire squad team members had assembled and donned their firemen’s outfits and mobilised the firefighting equipment. The engine room ventilation was stopped and fire dampers were closed at about 1715. The Chief Engineer also activated the main engine emergency stop and interrupted the electrical supply to the engine room.
In the meantime, the fire squad team had already started to tackle the fire but by 1725, it had spread to the generators’ area and it became evident that it was beyond control. On the basis of the feedback provided from the engine room, the Master decided to activate the fixed CO2 system and flood the engine room to extinguish the fire.
Following the application of the relevant procedures, the fixed CO2 system was activated at 1730. The company was informed and the vessel remained adrift in a black out condition, about 50 nautical miles off the coast of Hong Kong.
By 0839 the following day, Askara’s engine-room had cooled enough to allow access to the crew members for an assessment of the fire damage.
It was established that the immediate cause of the fire was hot fuel oil spilling from port HFO storage tank and coming in contact with the main engine exhaust manifold.
During the course of this safety investigation, the company took the following safety actions:
• All bunker system components (including valves, flanges, sensors drains, etc), were identified and marked with a stencil.
• A new bunker tank component checklist was included in the safety management system.
• Tool box meetings and risk assessments have been included in company-run seminars for senior and junior engineers.
• An internal investigation was carried out in accordance with Section 9 of the ISM Code and the findings were distributed on board company ships.