Murdock and Roselli, however, would wear their dry suits. They wouldn’t provide perfect protection against the bitter cold of the North Sea depths, but they wouldn’t require as much preparation and fitting out as the high-tech hot-water suits that Bouddica’s BGA deep divers normally used when they were servicing the bottom pipelines and installations.
The main reason Murdock had elected not to use his SEAL gear, which should still be floating in the tethered swim bladder beneath Alpha, was that it was rebreather gear, rated for use only to a depth of about thirty feet. Pure oxygen from a rebreather became toxic at the pressure of greater depths.
They couldn’t even rely on normal SCUBA gear at 240 feet. SCUBA used standard oxygen-nitrogen gas mix, the same as normal air, but at depths much below one hundred feet, the standard mix became dangerous as well. Nitrogen narcosis, sometimes called “rapture of the deep,” was an affliction every diver developed to one degree or another when breathing nitrogen at greater than about three atmospheres’ pressure. The best medical evidence was that at depths beyond one hundred feet, the nitrogen actually began interfering to a greater or lesser degree with the impulses passing from neuron to neuron in the brain. Concentrating on the task at hand, training, and experience could overcome nitrogen narcosis to a certain degree… but cold water and fear could increase a man’s susceptibility.
The other danger, of course, was decompression sickness. Diving on straight air meant that as the pressure went up, nitrogen in their bodies would be forced into their body tissues. If they surfaced too fast, nitrogen bubbles could form in a man’s bloodstream — fizzing up just like the carbon dioxide in a shaken soda can when the pop top was pulled. The bubbles would collect in his joints and cause an exquisite agony; some might clog vital arteries in brain or heart or lung. The condition was called “the bends,” and it was both crippling and deadly.
Murdock and Roselli would be diving on heliox, a gas mixture that substituted helium for nitrogen. Helium would completely eliminate the dangers of nitrogen narcosis. While it wasn’t impossible to get the bends on heliox — helium bubbles could form the same as nitrogen bubbles — the danger of decompression sickness was much reduced on a deep dive when the divers breathed helium, and at extreme depth breathing was easier too.
Of course, both men would sound like Donald Duck when they spoke.
Their headgear consisted of full-face masks, with built-in radios. Radio signals didn’t travel far underwater — no more than a few yards, in fact — but the mask transmitters would enable Murdock and Roselli to communicate as long as they stayed close to one another. There were also pickups on the pylons supporting Bouddica Alpha, so listeners on the surface would be able to hear them once they were within range. Helium, however, changed a diver’s voice, pitching it much higher and giving it a squeaky, cracking effect that grew worse the deeper he went. The distortion was literally known as the “Donald Duck Effect.”
More serious was the fact that helium was a far better conductor of heat than nitrogen. Breathing heliox, the divers would be far more susceptible to the intense cold.
But they would face that when they had to.
“Okay,” Murdock told the others in the room as Bouddica’s senior dive master buckled on an extra set of weights, investing him like a squire assisting a knight with his armor before a medieval tourney. “Roselli and I will go first. The rest of the SEALs get their chance as soon as you can get gear together for them, but this will be volunteers only. Don’t dive until something happens to us… or until we call you down. Everybody else, except absolutely necessary personnel — and volunteers only — get the hell out.” He glanced at his watch. “We probably still have two hours or so. But we can’t count on much more. Everybody understand?”
There were nods and muttered agreements from the others in the room. Murdock exchanged nods with Roselli, then slipped the mask down over his face. A quick radio check — all okay — and he and Roselli flip-flopped their way across to the open wall. Murdock clung to a nylon line with his right hand, a line that led back to a winch mounted on the diver bay close by the door. The shackle on the free end would let him hook onto the eye on the end of the atomic bomb; they’d be able to hoist it up from here once he signaled the hookup complete.
As long as there were no booby traps Pak hadn’t told them about, the bomb could be easily disarmed then.
All they had to do was get the rope and shackle to the bomb.
There was an elevator in the nearest pylon that should have whisked them down to the bottom, but it had never worked right. Squire Murphy, once again. Most BGA divers used a complex elevator arrangement that lowered them down the outside, but it would take too long to break that out now. Instead, they would jump from the lowest level, a drop of about forty feet, then swim for the bottom, some forty times a man’s height below. Roselli went first, stepping off the edge of the door and vanishing as he fell.
“Lieutenant!” Wentworth called. Murdock paused in the open door, a step away from the night. “Luck, Yank,” the SAS colonel called. “We’ll be waiting for you. Right here.”
Murdock gave him a thumbs-up, then stepped after Roselli into darkness.
Chun heard the first splash as something heavy landed in the sea less than twenty meters from where she was hiding. She turned in time to see a dark shape — obviously a fully suited diver — plummet out of the sky and land in the water, close by the boiling foam left the first entry.
Divers… two of them. It wasn’t hard to guess what they were after.
It was time for her to execute her plan.
She’d been hiding here behind the massive winch on the tug’s after deck, shivering, trying to stay warm, trying to stay hidden, wondering what to do. The submarine resting on the cradle nearby offered her a possible escape, but she wasn’t eager to take that route. The minisub had a top speed of only a few knots; it wouldn’t be hard to track the machine and destroy it.
Besides, she knew that Chong Yong would not have dropped the bomb without arming it, knew that he would have set the pressure switch to detonate within a few hours. It was her duty to stay behind, to make sure no attempts were made to retrieve it.
One SAS trooper stood guard by the minisub. He was standing with his back to Chun, watching the spot in the water where the two divers had vanished. Rising smoothly from her hiding place, Chun fired into the man’s back from a range of five meters, the sound-suppressed burst from her stolen H&K snapping his spine and propelling him forward into the water.
Then she was running for the sub. The tarpaulin had been removed earlier, the hatch on top open. In seconds, she’d vaulted up to the craft’s top deck, scrambled into the hip-snug conning tower, banged the circular hatch shut and dogged it, then dropped into a control room so tiny she could touch opposite bulkheads without even stretching.
The cradle was equipped with hydraulics, controlled from inside the cabin. Chun went down the line of memorized switches… power on, lights on, cabin pressure on, batteries on, diving planes to manual, blowers on, steering enabled, hydraulics on…
With a whine and the creak of shifting mass, the stern of the little sub began elevating. Chun lay on her belly at the pilot’s station, her entire world narrowed to banks of switches and controls, and a line of three small portholes giving her a view forward and slightly to either side. The water was coming up as the Squid’s nose tipped down. The stern was tipping higher… higher…