ANOTHER Collins submarine goes close to disaster through equipment failure
The story below does not mention the Dechaineux incident but I will
JUST after midnight off the coast of Perth, navy submarine HMAS Farncomb was slicing below the surface of a rough sea when its engines cut out.
For the 60 men and women aboard the Collins-class boat, the next few minutes would be among the longest of their lives. Like a Hollywood thriller, the sailors found themselves grappling with a double engine failure followed by a terrifying, powerless descent towards the bottom of the Indian Ocean, stemmed only by the cool actions of a veteran commander.
This real-life drama, which took place at 12.30am on August 23 about 20km off the northwest coast of Rottnest Island, was not revealed by Defence at the time. When quizzed by The Australian the following day, officials gave only a brief, sanitised version of the incident, omitting key facts while praising the competence and training of the crew for following "standard operating procedures".
Many of the Farncomb's crew are far from relaxed about what took place under the Indian Ocean that night. "I said to myself, 'I'm gone, I'm dead',' one recalled thinking as the powerless submarine began to slide towards the ocean floor. Another on the submarine has told friends: "When we started going down, I just tried to accept it and make peace with myself."
In their eyes, the Farncomb incident came uncomfortably close to being Australia's worst naval tragedy in almost 50 years. Defence denies this, claiming crew had "positive control of the submarine throughout the incident".
An investigation by The Weekend Australian reveals discrepancies between Defence's official account and first-hand accounts now circulating in Perth from the Farncomb's crew.
What is undisputed is that Farncomb was conducting operational training in the waters northwest of Rottnest Island soon after spending a month in dry dock where it had its emergency propulsion unit replaced. In charge that night was veteran submarine commander Glen Miles, a ruddy-faced archeology and rugby enthusiast who once served on the old Oberon submarines and who was dux of his submarine officer's course. Also on board was a Sea Training Group assessing the crew's competence.
Shortly after midnight, the Farncomb was gliding at a periscope depth of 20m while undertaking a routine known as "snorting", where air is drawn into the submarine to run the diesel motor in order to recharge the boat's batteries. At 12.30am, without warning, a fault in the control switchboard of the submarine's electric motor caused the motor to stop. "Propulsion failure, propulsion failure" rang out across the Farncomb's address system, as crew ran to emergency stations.
Propulsion failure in a submarine is both uncommon and serious, but it is usually quickly offset by a procedure that allows the motor to be restarted in emergency mode. Faced with a powerless, slowing submarine in a rough sea, Commander Miles ordered the submarine to glide down from its depth of 20m to 50m in order to assess the problem.
It was a bad time to lose propulsion because it meant the submarine had to stop snorting. When snorting stops, a submarine instantly becomes much heavier because the snort masks and exhaust, which are outside the hull, fill up with water.
Normally the submarine balances this extra weight by pumping out compensating water, but this takes time. So Commander Miles suddenly found himself in charge of an overweight submarine with no power, sliding south.
By the time the Farncomb reached its desired depth of 50m, there was more bad news. Despite the frantic efforts of crew, they could not get the emergency mode of the main motor to work. Defence said this week: "The reason for delay in restoring propulsion in emergency (mode) remains the subject of a technical investigation."
Commander Miles faced a full-blown emergency. He had lost both his engine and his emergency back-up.
Defence declined to tell The Weekend Australian how deep the Farncomb sank, saying only that such details were "not openly discussed".
According to several crew members' versions, the Farncomb slowed to a virtual halt, tilted nose up and began to slide backwards towards the ocean floor. The tilt was so steep that sailors eating in the mess room had to grab their dinners as they slid off the table. Those in the sleeping quarters found themselves "on top of each other".
In the control room, Commander Miles was not panicking, but was watching the sliding depth gauge hoping that the propulsion motor would restart before the Farncomb sank too deep. He knew that, as a last resort, he could take the dramatic step of blowing the submarine's ballast tanks to stem the descent.
In those long, agonising seconds - perhaps a minute or more - as the submarine kept sliding towards the seabed, some of the Farncomb's crew started to consider the unimaginable. The submarine is believed to have been operating in more than 1300m of water off the continental shelf. This meant that if they continued to sink, the water pressure would crush the submarine and its crew long before they hit the seabed.
Their fate would have mirrored the 129 men of the US navy submarine USS Thresher, which was crushed by water pressure when it sank in the Atlantic Ocean during deep diving tests in 1963.
Crew accounts of how deep the Farncomb sank differ. The consensus is that it plunged to between 150m and 190m. If so, this is uncomfortably close to the submarine's permissible deep diving depth, the actual figure of which is classified.
At some point during the Farncomb's powerless descent and without any sign of life from the motor, Commander Miles ordered a partial blow of the submarine's main ballast in which air expels water from the ballast tanks, making the boat lighter.
"Because the submarine was still heavy as compensating water was being pumped (out), the commanding officer chose to blow main ballast to arrest descent," a Defence spokesman said.
What happened next depends on whose account you believe. Defence says that the initial ballast blow stemmed the descent and that the Farncomb actually began to slowly rise. Some crew members maintain the submarine was still sinking, although at a slower rate.
Either way, Commander Miles then decided to take the most drastic step available to a submarine commander: to order a full emergency blow of all ballast tanks. "That was the last resort available to the crew at that time and if it did not work, there would have been no hope for them," one source said.
To the enormous relief of its crew, the plan worked and the Farncomb - powerless, overweight and stricken - began to rise at last. Once back on the surface and with no further ballast to blow, Commander Miles ordered the crew to try again to get emergency propulsion back. This time, they succeeded, regaining emergency propulsion and the Farncomb was able to limp back to Fremantle.
Navy argues that Commander Miles was not completely out of options because there was an autonomous Emergency Propulsion Unit on board that was manned during the incident but was not activated.
Navy claims the EPU "would be sufficient to maintain control of the submarine in such situations". Submarine experts dispute this and say that, if this was so, why did Commander Miles not use this option rather than order the more drastic blowing of all ballast tanks.
"The EPU is only designed for surface propulsion and there is no way that it could have controlled a 3000-tonne submarine heading backwards towards the seabed," said one expert, who asked not to be named.
The incident will not help the troubled reputation of the Collins-class fleet, which has been plagued by technical problems, but it will be seen as good example of the ability of a well-trained crew to get out of sticky situations.
When asked this week by The Weekend Australian how serious the Farncomb incident was, Defence avoided giving a direct answer, saying only that "standard procedures were employed to recover from this propulsion failure while snorting". "These procedures are regularly exercised," Defence said.
The Farncomb has been repaired and is now back at sea, but at least one crew member, an engineer, is said to have stayed behind in Perth to deal with the stress of what happened on August 23.
As one submariner put: "This (incident) shows that even when things go wrong on a submarine, there is usually a way to get out of trouble. "But those blokes would have been very glad to get home."