Instead Voortrekker's stern reared up, higher and higher, lifted by the blast, throwing Van Gelder and ter Horst forward against their workstations.
'Fifty-two degrees down bubble!' the helmsman shouted. 'I can't control the boat!' A soul-piercing alarm bell filled the air. 'Reactor scram!' came over an intercom. ' Excessive trim reactor scram!' The overhead lights dimmed immediately, switched to batteries as Voortrekker's turbogenerators
wound down. Then Van Gelder heard the inevitable: 'Control, Maneuvering, we've lost propulsion power!' The sub's vibrations changed in character, nastier than before.
'We're in a jam dive!' the helmsman screamed. 'Cruise by wire's inoperative! Backup hydraulic system's failed!' He and the diving officer twirled their control wheels uselessly.
'Fire in the forward fan room,' came over the intercom. 'Flooding through the main shaft packing gland.'
'Diving Officer,' ter Horst said, 'pump all variable ballast. Pump out the safety tanks.' The intercom began to hiss and squeal, becoming unintelligible. Ter Horst tore a soundpowered phone rig from a crewman lying on the deck. The man's neck stretched like rubber and Van Gelder realized he was dead. The body slid downhill.
'Silence on the circuit!' ter Horst snapped, then, 'Engineering, engage sternplane manual overrides. Can you give me back full revs on batteries?' Ter Horst listened, frowning. 'Then lock the shaft and use the propulsor as a water brake. We've got to stop this dive!'
Van Gelder glanced at a depth gauge. They'd just passed 2,500 meters, rate of descent increasing fast. This far down even Voortrekker's ceramic hull compressed, reducing their buoyancy further.
'Captain,' Van Gelder said, 'our momentum's much too high. Recommend emergency main ballast blow while we still have the chance.'
'That was a three-KT warhead out there,' ter Horst said, 'if not more.'
'I know, sir. But we're too heavy now with the heat and gas bubbles around us.' The ocean's supporting density had just dropped out from under them. 'Our crush depth's coming up fast!'
'Surfaced into those tsunamis, we could turn turtle easily,' ter Horst said, 'spill air from the bottom of the ballast tanks and sink, even do a full three-sixty, smashing everyone and everything inside.'
Van Gelder nodded. Which was the better way to die?
'Engineering,' ter Horst said into the bulky mouthpiece, 'status on the diveplanes? Can you shunt past the bad main motor breakers?' He paused for the response. 'They need more time.'
'Captain!' Van Gelder urged as he watched the depth gauge. 'We've got barely sixty seconds till the hull implodes!'
'Very well,' ter Horst said, sighing, 'it's the lesser of two evils…Diving Officer, emergency-blow the forward main ballast group.'
High-pressure air screeched like a strident harpy, forcing its way into the tanks outside the pressure hull. Enough leaked through the distribution manifold to pop Van Gelder's ears.
'Number One,' ter Horst told him, 'lay forward and steady the damage control parties. See to that fan room fire.'
As Van Gelder stood up awkwardly, the control room began to fill with wispy smoke. He ordered the crewmen into respirators. Some cursed in pain as they put masks to bruised and bloodied faces, then aided unconscious or stunned neighbors who flopped sideways strapped into their chairs. Van Gelder reached for a walk-around breather set stowed under his console.
'We're still going down,' ter Horst said. 'Diving Officer, give the forward ballast tanks more air.'
'Sir,' the senior chief said, coughing, 'it'll expand too much as we go up and we'll lose bubbles through the bottom vents. They'll make a datum topside.'
'Christ, man, that doesn't matter now!'
Van Gelder staggered as an aftershock hit. The deck tilted even further in spite of the bow tank blow. He reached out desperately to avoid a long fall down the forward passageway. He grabbed a stanchion on the overhead and lunged to safety, dropping his air pack on the way. He wound up pinned by gravity beside the diving officer and helmsman. He heard his respirator crash against a transverse bulkhead somewhere forward. That could have been my skull, he told himself, then wondered how the fire fighters were making out.
'Emergency-blow stern ballast tanks,' ter Horst said. 'Use all the air you've got.' Van Gelder's ears hurt more, but nothing happened.
'Dammit,' ter Horst said, 'it's not enough. Fire the hydrazine gas generators.' Van Gelder knew the onetime-use chemical cartridges were a last resort. He heard them igniting in the ballast tanks, like missile engines on a hot run in the vertical launching system.
The boat shuddered, then seemed to stop and think about it, still with a frightening downbubble. The helmsman shouted that the sternplanes had been freed. He put them on full rise but then they jammed again. Voortrekker started coming up. The helmsman called out their depth every hundred meters, then every two hundred as the boat kept on accelerating, driven now by massive and increasing positive buoyancy.
'Sonar,' Van Gelder said automatically, holding on for dear life, 'any surface contacts?' The sonar chief gestured helplessly. 'Sir, it's impossible out there.' His voice sounded distant, muffled through his breather mask.
'Collision alarm!' ter Horst said into the sound-powered phone. 'Talkers relay to all hands: Emergency surface, stand by to broach. Rig for fallout, do not open air induction valves, do not man the bridge.'
Van Gelder eyed the speed log. The boat moved in reverse, rising by the stern.
'Raise the photonics mast,' ter Horst said. Still strapped in at his console, he activated the viewing screens that hadn't been blown out. He used the 'scope joy stick to look aft and upward.
Van Gelder stared at a screen. At first there was nothing, then he saw an imageintensified dull glow. Quickly the picture brightened, showing the greenish underside of waves, getting closer and closer. Van Gelder realized the waves were very large, churning and breaking horribly, not like normal windblown swell. Suddenly Voortrekker burst through, and ter Horst worked the joy stick.
Van Gelder watched their stern uncover, white water swirling off the hull, Voortrekker a massive projectile thrusting up into the sky. He could see the control surfaces and the cowling of the pump-jet, exposed naked in the air. Van Gelder's stomach rose to his throat as the sub topped out in her trajectory, halted, then smashed back down. She thrust the chaotic seas aside, water spraying from beneath her, then plowed under, reburying the hull. She seemed to stagger, then came up again, fighting against the violent ocean, settling on an even keel. At once she started to badly roll and pitch, steerageway gone, visibly stern-heavy now.
'Do not counterflood,' ter Horst ordered.
Van Gelder struggled to his feet, his attention glued now to the monitor, taking in the scene with a practiced sailor's eye. Foam sprayed off the frenzied wavetops, streaming away beyond the stern.
'My God,' he said, 'the wind's blowing to the south.' Van Gelder knew that thanks to planetwide air circulation driven by the sun, the winds of the Southern Ocean were the steadiest on earth. They roared down off the high mountains of central Antarctica, spreading northward toward the coast in all directions. To conserve angular momentum while moving farther from earth's axis of rotation, the air had to lose ground to the planet's spin, veering left: the Coriolis force. The wind at this latitude always blew to the northwest, Van Gelder told himself. Always.
Ter Horst shifted the periscope head, searching. He switched to wider angle, then found what he was looking for. 'Five thousand meters tall already, maybe The overcast had dissipated from the heat, and the base surge had mostly cleared: the mushroom cloud thrust higher as they watched. The golden-yellow fireball cast shadows north along the wavetops, canceling the sun.
'Air's being sucked in toward its base,' Van Gelder said. A satanic low-pressure front, he told himself, driven by staggering thermal forces. The superheated air formed nitric oxides, like in smog, adding a reddish-orange tinge.
'Look at that,' ter Horst said. 'The entrained steam's condensing now…It's giving the pillar a nice fluffy white appearance.'
In a mockery of normal weather the man-made cirrostratus cooled.
'It's started to rain,' Van Gelder said. He knew droplets falling against the pillar's updraft would add their static charges to the massive ones created by the blast.
'Lightning,' ter Horst said. 'Wow.' He actually smiled as the monitor flashed again. Each discharge's crack
