A cable fire seems to have been the cause of a the fire that led to the deaths of two naval officers in the accident on INS Sindhuratna last week according to the preliminary findings of the board of inquiry. According to reliable naval sources, the fire occurred in plastic-covered cables connecting the batteries to the electrical systems of the submarine.
Once the fire alarm went off, Lt Commander Kapish Muwal and Lt Manoranjan Kumar rushed to the spot but collapsed after inhaling the dense black smoke, according to the preliminary findings. The captain of the submarine, Commander Sandip Sinha rushed into the third compartment to try and rescue the two officers but couldn't do so because of the dense black smoke, naval sources said on the condition of anonymity since they are not authorized to speak to the media.
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In fact the Freon fire fighting system of the submarine was also activated but it added to the confusion on board. "The Freon system tends to suck out all the oxygen out of the compartment to kill the fire. So the two officers must have tried to push out the other sailors from the third compartment when the fire occurred and they could have collapsed," said Cmde A J Singh (retd) who was the executive officer of this submarine in the early 1990s.
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The BoI's initial findings also show that the batteries were not the cause of the fire and instead, it was material failure. "The batteries had completed only 60 cycles out of the 200 cycles and were relatively brand new," a senior naval official familiar with the inquiry told HT. The cables are coated and insulated with plastic components and a material failure seems to have caused a short-circuit leading to the fire. "Many times the hydrogen concentration in the battery pit go up, and that also helps spread the fire," Cmde. Singh (retd) said.
The battery pit is a small enclosure in a compartment and can allow only one person at a time. The sailor's compartments are attached to the battery compartment and the two officers are believed to have been busy evacuating the sailors when they were sealed off. The captain, Cdr. Sinha also tried to rescue them but couldn't. He then returned to the bridge and surfaced with the submarine before collapsing from the poisonous fumes that he had inhaled. He was also evacuated and was released from the Intensive Care Unit on Monday morning.
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The chief of naval staff, Admiral D K Joshi, resigned from service taking up moral responsibility for the accidents that had taken place in the last 11 months. However, since the cause is emerging to be material failure, it seems that there was no evidence of human error that led to this particular accident.