It took skilled operators to disentangle the sounds, but it could be done. In 2008, the UK’s underwater listening post in Gibraltar was able to pick out the propellers of the QE2 as she pulled out of New York. But while the metallic thrashing of a civilian propeller might be easy to detect, when cloaked with military sound insulation and muffled by distance, the signals become harder to read. For all humanity’s attempts to scrape it clear of life, the sea is not a silent place. Snapping shrimp are infamous among sonar operators for the din they create, a marine equivalent of a field of screeching crickets. And whales also use the Deep Sound Channel to communicate with astounding acuity. Some scientists believe that the blue whale – the biggest creature ever to have lived on this planet – is able to distinguish between individuals across the entire Pacific. Other sounds are more mysterious still. In the 1970s, sub-sea snoops were blasted with a noise that has remained unidentified to this day. It was loud enough to have been an underwater landslide or earthquake, yet its waveform appeared to be biological in origin. If it was, then whatever produced it would have had to be bigger than a blue whale.
Approaching the array, Gold felt like he was looking at such a monster on the sonar. His role in the exercises that he’d taken part in over the years was always to find the submarines that were playing dead. Although such diesel-electric and nuclear craft can be huge, their hulls are usually coated in rubbery tiles. Aside from providing valuable heat insulation, they are specifically designed to muffle the probing pings of active sonar. A 100-metre submarine could have a sonar paint that was easy to miss. But not this hydro-phone array.
‘Okay, let’s hold this depth and get over there,’ muttered Gold.
‘Start feeding out there, Will, slow and steady,’ Nuttall said into the deck radio, and started pushing Scorpio through the water towards the looming shape on the sonar.
The room was getting hotter, and Nuttall was aware that beneath his long mop of hair his shirt was already starting to stink. He’d not had a chance to change since leaving Barrow-in-Furness. He put it out of his mind and concentrated on keeping his eye on the direction indicator, the sonar and the depth pressure gauge while continually scanning the instruments and warning lights for any sign of trouble. So far, so good.
Less than five minutes later, he slowed the forward thrust. The sonar reflection was menacingly close, but still he couldn’t see anything in the unfamiliar black and white of the front camera display. Then something began to appear. A huge, curving wall of barnacle-coated metal filled the screen.
The video, stills and drawing they’d seen showed the AS-28 up at the end of one of the cylinders with the structure on its starboard side, so Gold told Nuttall to head to port.
Twisting the joystick, Nuttall turned the vehicle in that direction and started heading along the side of the array, keeping the looming, sealife-encrusted metal on the right of the screen. The visibility was excellent compared to what he was used to. In the North Sea you’d often be lucky to see a metre, but here he could see more than ten. Scorpio pushed onwards through the light snow of sediment, but all that appeared from the darkness was more featureless metal until the enormous tube suddenly ended.
There was no submersible. Podkapayev began talking excitedly, and the interpreter explained that they must go around to the other side of the array and continue to the other end. Gold and Nuttall looked at one another. That meant having to loop the umbilical over the top of the array. In the rush to deploy Scorpio, KIL-27 had been moored with the array between the ship and AS-28. Either that, or their improvised mooring system was moving a whole lot further than it should have been. Neither thought was particularly reassuring.
‘We should reposition,’ said Gold. ‘If the umbilical gets stuck we’re not going to be helping anyone.’
But moving over to the other side of the array could take hours, given how long it had taken to get into this position in the first place. After a short discussion, Gold nodded to Nuttall, who spun Scorpio around and began flying back along the top of the array, keeping it slightly to his right. With the vehicle travelling as fast as it would go – about two knots, or walking pace – the tubing passed beneath like an outsize pipeline, reminding both men of the endless oil and gas pipeline surveys they’d done in their offshore existences.
The array was now occupying the whole of the right-hand side of the long-range Ametech sonar display. Gold began twisting a knob on a second console, the high-frequency array. Pinging at 675 megahertz as opposed to the 100 MHz on the long-range, the colour Tritech was much more twitchy, but much more sensitive. Tune it right, and you could pick up the echo of a 5-litre paint pot sitting on a sandy bottom. The colour gave a sense of how hard the objects up ahead were, ranging from blue for non-existent, through hues that got warmer as the obstacles became harder until they became white for solid metal. With both sonars now groping forward beyond visual range, Gold suddenly cleared his throat.
‘All right, what’s this little beastie now?’ he said. A white lump had appeared on the high-frequency array. ‘Slow up a little there, Pete.’
Sunday, 7 August
SS + 67 h 32 mins
When word came from the surface that the British rescue submarine was on its way, Gennady Bolonin flicked on the outside navigation lights of AS-28. It might use up valuable battery supplies, but looking at the state of the crew anything that would bring help faster was worth it.
Back in the aft compartment, huddled on the floor, the men’s faces were frozen masks. Their eyes were dull compared to the glistening of the weeping submarine walls in the red emergency light. If there was hope here, it was deeply hidden, thought Bolonin. Then there was a murmur from the huddle. It was Milachevsky. He’d heard something.
There was a visible straining of ears, and then Bolonin heard it too, the almost unbelievable murmur of the foreign machine. It had an electrifying effect. Milachevsky hauled himself up and through the hatch to the forward compartment to the periscope. It was a Herculean effort that left him panting and grasping on the handles as he scanned the water around them. He couldn’t see anything.
The murmur seemed to be coming down straight on top of them. How had the British managed to locate them so precisely? It seemed miraculous.
Standing at the periscope, Milachevsky’s body tensed. ‘It’s here,’ he said, his voice a hoarse whisper. ‘I can see the lights. It’s here.’
Sunday, 7 August
SS + 67 h 35 mins