“Sonar, Conn,” Houser’s acerbic voice rang on the communication circuit, “what’s the status of the incoming torpedo?”
Sanderson’s reply was equally caustic.
“Still incoming.”
“Any idea of range? Or speed?”
“Conn, Sonar, no.”
Schramford’s voice came on the circuit next. “Conn, maneuvering, we’re overpowering the reactor now, limited by main engine bearing temperatures, reactor power steady at one three eight percent.”
“We’re getting …” Kane craned his neck and peered at the speed indicator, noticing the deck’s vibration seemed about the same … “forty-two knots. Is that all she has, Eng?”
“Sir, any more and we’ll melt the mains or grind up the reduction gear. As is we’ll sustain some core damage and higher radiation levels.”
“Eng, you get me away from this torpedo and I’ll buy you a brand-new plant,” Kane said.
“Captain, presets loaded and confirmed,” Follicus broke in.
“Very well, Weps,” Kane replied. “As soon as we’re done shooting, get the crew working the reload.”
“I’ve already told them, sir.”
Kane stepped back from the attack center to the periscope stand, where he could see the entire crew in the stuffy room.
“Firing point procedures, tubes one and two.”
“Ship ready,” Houser drawled.
“Weapons ready,” Follicus said.
“Solution input,” Mcdonne said, obviously unhappy at shooting a torpedo without contact on the Destiny, the artificial range and orbit point a gamble.
“Tube one, shoot on programmed bearing,” Kane said.
“Set,” from the attack-center Pos Two console’s Rodney Olson as he locked in the orbit point for the torpedo in the computer, sending it to the torpedo in the tube in the lower level deck.
“Stand by,” Follicus said, taking the firing trigger on the firing panel to the nine o’clock position, completing the launching circuit in the computer.
Two decks below a small solenoid valve opened in an ultrahigh-pressure air line leading to the firing ram, a large piston with the high-pressure air on one side and water on the other. The air side of the ram became loaded with the air at over 3,000 pounds per square inch, the surface area of the piston translating the pressure to a force of 200 pounds per square inch as it pushed against the water on the other side of the ram. The water side realized the same pressure spike, the pressure in the torpedo tanks soaring, the water spilling into vents in the aft end of the tube, rocketed the torpedo from the tube. In little more than a second two tons of Mark 50 torpedo had been accelerated to three g’s and cleared the tube. The ejector ram, now at its end position, came to rest, the air side venting inboard in a tremendous crash, pressurizing the entire ship and temporarily deafening the torpedo-room crew in spite of their Mickey Mouse ear protectors.
In the control room David Kane’s eardrums slammed from the pressure of the torpedo launch. Before his hearing returned to normal he barked the next order:
“Tube two, shoot on programmed bearing.”
Seconds later the second torpedo left its tube and turned back around to the east on a medium-speed run to enable.
For the next fifteen minutes, the Nagasaki torpedo gaining steadily on it, the Phoenix launched torpedoes every forty-five seconds, the weapons leaving the ship and turning back around to head east.
After twenty-three torpedoes had been launched, Follicus turned around to face Kane and Mcdonne.
“Sir, the last torpedo is loaded in tube four. Should we shoot or save it?”
Mcdonne spoke up, knowing Kane would want a recommendation.
“I say save it. Captain. Never know when we’ll need an insurance policy.”
Kane decided he’d be damned if they found a spare torpedo in his hull’s wreckage … if it came to that.
“No, XO. Firing point procedures, tube four.”
When the last weapon had left the ship, leaving the torpedo room empty, the torpedoes enroute to or already at their preprogrammed hold points waiting for the emergence of the Destiny, sonar chief Edwin Sanderson clapped his hands against his headset, his eyes nearly bulging out of his head.
“Conn, Sonar,” he called, his iron control lost for a moment as he spit out the words — “Nagasaki torpedo is going active. Range gate shows it’s within 2,000 yards.”
Chapter 17
Sunday, 29 December
The guidance-and-attack computer of the Nagasaki torpedo had half the power of an American-made Cray supercomputer but also took up only a cubic meter of space aboard the thirteen-ton torpedo. The sonar system of the weapon was sophisticated and sensitive, able to hear a surface warship fifty miles away, a submarine thirty to forty in ideal sound conditions with a target radiating a typical amount of noise. The power of the computer was used mostly in sifting the several hundred thousand gigabytes of sound data it picked up from the sea, including tonal frequencies in a narrowband processor, all the analysis done in real time, just as Hegira’s Second Captain system did, except that instead of displaying the data, the torpedo’s computer relayed the analysis to the target-interception subroutines. The interceptor programs calculated the swiftest interception course and speed to the target — the torpedo attempted to avoid unproductive tail chases, instead aiming itself toward a point in the ocean where the target would be in the future, a sort of smart football aiming not for the wide receiver but where he would be at the exact time of reaching the field. In this case the target parameter calculation was predictable since the target submarine had put the torpedo due astern. The Nagasaki could only aim for the target and order the propulsor to spin at maximum speed, giving it 128 clicks of forward velocity to the target’s mere seventy-seven.
The speed advantage had the torpedo steadily closing the distance to the target, gobbling up the sea between hunter and prey. The weapon had, in effect, been patient, content to drive in at maximum thrust and click off the minutes, waiting as the target grew nearer and nearer. Still, it was not easy being patient with the knowledge that the target was just ahead; had the unit been a cheetah pursuing a gazelle, its mouth would have been watering furiously at this point.
Soon the target was within two kilometers, the range determined by driving a slight wiggling course to see how the bearing to the target reacted. The short range caused the targeting functions to activate the unit’s sonar set — passive listen-only sonar was fine for pursuit of a loud contact but not good enough for the exact placement and detonation of the six metric tons of shaped-charge plastic explosive in the warhead. If the torpedo attempted to hit the target with passive search sonar, with this high closing speed, it could experience a bearing error that would cause the unit to go sailing past the target and have to turn around and continue the chase. The active echo-ranging came on, illuminating the sea around it with a powerful medium-pitched sonar pulse, transmitting the pulse at power high enough to generate steam vapor bubbles at the nose cone. After the pulse the torpedo went silent and listened for the return, which came back a fraction of a second later, the sound distorted by the target submarine’s rotating screw, the frequency downshifted to a deeper pitch by the target’s motion away from the sonar pulse. The target position in the computer’s mind needed to be adjusted slightly, the range a bit farther than the torpedo had originally thought.