Piranha: Firing Point mp-5

by Michael Dimercurio

  “Nav, latest bearing to the convoy.”

  “Sir, zero nine four.”

  Chu trained the scope to the east He increased the optic power to medium, and the horizon seemed to grow closer. Yet there was nothing coming. He snapped his right grip again, increasing the power to high, with 24X magnification. The sea jumped slightly in the view, making it harder to see clearly, since the slightest movement of the ship made the scene outside jump. But even in 24X the horizon was clean.

  “Second Captain,” he muttered, “superimpose geographic plot on top of reticle.”

  The computer god’s-eye view came up in a sort of heads-up display, superimposed on top of the view outside.

  The plot snowed up as the direction he was looking, and at the other end of the bearing line at twelve o’clock were several dozen hostile-contact diamond symbols.

  The distance to the convoy was shown as being nineteen kilometers. He bit his lip — he should be able to see the tall masts of the aircraft carriers by now, or at least the lead vessel.

  “Ship Control, change depth to twenty-one meters keel depth.” That would stick the periscope mast skyward by nine meters, a telephone pole sticking up above the sea. His new “height of eye” should make a difference.

  As his view moved farther from the waves, the ship coming shallower, the horizon changed. What once before had been a sharp line between sky and sea now blurred slightly.

  And now visible were three black spots on the horizon.

  Chu focused high power on the spots, finding them to be just portions of the tall islands, the massive hulls of the ships still hidden by the curvature of the earth.

  He then applied double-high power with a trigger on the right grip, increasing power from 24X to 48X, but the first spot on the horizon jumped around, tough to keep it in sight Even in the bouncing image, though, Chu could see that it was the island of an aircraft carrier.

  “Three surface contacts, gentlemen. Bearing zero nine five to the center target. Contacts are hull down but approaching rapidly.” Chu cleared his throat, enjoying the moment. “Designate the central carrier target number WT-1. Target to the left is WT-2, target to the right is WT-3. Prepare for torpedo attack, tube assignments to follow. Ops Officer, all weapons nominal?”

  Chen Zhu, at the weapon console in the opposite corner of the room, piped up. “All twenty-four primary torpedoes nominal. Admiral.”

  “Very well, all tubes and all weapons shall be set to ultraquiet swimout, all speed settings to ultraquiet slow speed, shallow-draft approach, immediate enable. If we are detected or if we need to hurry, we’ll switch to impulse mode on the gas generators and go to highspeed transit. Now, tube assignments… Target WT-1, central aircraft carrier, assign tubes one and two. Target WT-2, left carrier, assign tubes three and four. Target WT-3, five and six.”

  “Aye, sir,” Chen said. “Tube assignments set and coming up on your heads-up display now.”

  The tube assignments flashed up for a moment, the geographic plot vanishing. The three carriers were closing, their islands becoming more focused, the ships grayish blue in the haze. Soon a row of other ships became visible, just the mastheads. And then the hulls of the carriers came into view, the center one first, then the ones flanking it.

  “Status, weps?”

  “Tubes one through six ready for launch, targets locked in on visual and sonar. Did you want to confirm range with the laser?”

  “No, it could give us away. Five seconds, gentlemen,” Chu said.

  The three carriers were now easily made out at 24X.

  “Ship Control, take us down to depth twenty-six meters.”

  “Twenty-six meters, aye.”

  “Three, two, one… tube one swimout!”

  “Tube one enabled in swimout mode, sir, and tube one is clear. Bow camera indicates weapon one away.”

  “Tube two swimout.”

  “Two enabled, swimout mode, camera indicates weapon away.”

  The launch sequence continued until the first six Nagasaki II torpedoes quietly left the ship, two en route to each aircraft carrier.

  * * *

  A kilometer from the Arctic Storm, several torpedoes slowly made their way to the aircraft carriers coming toward them, their passively listening sonars guiding them in. Over forty kilometers farther west, the two escort submarines cruised on at top speed, their sonars hearing nothing suspicious.

  Weapon number one, the first launched from the bow of the Arctic Storm, plowed through the sea toward the approaching convoy. Its onboard computer — small and simple, yet of vastly superior power compared to the original Nagasaki design — computed the distance to the target and the target’s heading and speed. The weapon was driving toward a point in space where its speed would cause its track to intersect the carrier’s. It was guided in mid-flight by a nose-cone sonar array, the front of the weapon a flat-panel cover over the transducer.

  Initially the weapon sonar was programmed to be passive listen-only, in receive mode. Pinging was rarely to be allowed, only if the unit lost its target in passive mode, but the target was so loud ahead that losing it would be impossible. The four massive screws of the target aircraft carrier thrashed loudly in the sea, coming from exactly the same bearing the weapon expected to hear it.

  According to the computer model of launching platform, ocean, and target position, the weapon calculated that it was halfway to the target. It had been set by the launching tube to “immediate enable” mode, meaning it was allowed to detonate at any time after leaving the tube rather than being required to count out a distance from the firing ship. Fully armed, the warhead was warmed up, awaiting only for the initial low-explosive charge to detonate.

  Aft of the nose-cone-mounted sonar transducer electronic package but forward of the onboard computer hardware was a ring around the torpedo skin linked to several redundant electronic modules making up the hull-proximity sensors. One sensor was magnetic, feeling the lines of the earth’s magnetic force, which were evenly spaced through the sea, but tremendously focused by the huge iron mass of a ship, a target. The magnetic sensors saw the distant spacing of the magnetic lines of force as white light and the gathering together of many lines of force, focused by the ship mass, as darkness on a white field. When the electronic module saw a dark spot of increased magnetism, they fed a positive signal to the computer’s warhead-detonation software. The second sensor was a wideband optical sensor, looking outward to the sea and able to sense the darkness below and the light above from the surface; a dark surface ship’s hull caused a positive signal to the detonator. The third sensor was a blue laser, shining outward in all directions to the sea, able to sense the presence of something that was not water or surface reflection. To it a hull stood out in stark contrast to the rest of the environment.

  For the surface-ship-target mode, the torpedo had enabled the magnetic proximity sensor and the blue laser, with confirmation coming from the less reliable visual sensor. The software wanted to see a “hard detect” on magnetic or a definite laser sighting, confirmed by optics if possible. The optics could be fooled by a sudden cloud obstructing the sun, and were fooled at night by the phosphorescence of a ship’s wake. A laser detect absent a magnetic detection would be a valid detonation signal, since the weapon would assume that either the magnetic sensor had failed, or that an antimagnetic anomaly device was in use. This was a new torpedo countermeasure employed by warships to alter the magnetic field surrounding the ship, a device that was only modestly successful.

  The weapon sped on at low-approach speed, 60 clicks, putting out its 186 hertz tonal into the water and emitting broadband white noise at 83 decibels relative to the ocean’s background noise, in the 50-decibel range. A broadband white-noise receiver would have picked out the weapon from a distance of ten kilometers. The 186 tonal sound-pressure level was emitted at 78 decibels, and would appear on the typical narrowband receiver at a distance of 30 kilometers. But the nearest broadband receiver was in the sonar dome of the destr
oyers behind the row of cruisers. The three aircraft carriers had no sonar systems, leaving that equipment to the cruiser, destroyer, and frigate hulls.

  The second row of warships, the Aegis cruisers, had bow-mounted sonar domes configured for active pinging sonar rather than passive listening, and were capable of streaming a Dynacorp T-65 and T-148 towed sonar arrays, but the towed arrays were fragile and required clear sea miles astern, making the array unusable while steaming in a tight formation. The cruisers also were not using their active sonar domes, since the active sonar would interfere with the passive sonar searches of the 6881 submarines ahead.

  In the third row behind the cruisers were the Aegis destroyers, which carried bow-mounted active sonars, all disengaged, and towed sonar arrays including the T-65, T-148, and T-22, all of which had been retracted and stowed for later use outside the battle formation. In addition, the destroyers carried a Seahawk V patrol helicopter with a dipping sonar transducer capable of active or passive sonar. The frigates behind the destroyers were similarly equipped, though the towed array systems varied. The only passive sonars engaged by the convoy were onboard the 6881 submarines, because a surface-ship sonar would hear so much broadband noise from the waves, hull flow, and screw that it would never hear an intruder submarine until it was within a fraction of a kilometer away. The surface ships counted on active pinging, when it was authorized, and a deep-running towed array that could dip far below the surface thermal layer, which kept noise from the surface channeled back to the surface and noise from the deep focused back deep. At the moment, though, these were uselessly stowed on large cable reels waiting for the ships to move to open water.

  The passive-searching 6881s, far over the horizon on the other side of the Arctic Storm, were crippled by their distance from the torpedoes going the opposite direction and by the fact that they were facing west and the noise was due east. Their bow sonar spheres and wide-aperture hull arrays were not positioned to hear astern, and the propulsion noise from the reactor and turbine systems as well as the screw noise made detection of astern noises impossible in any case. Both 6881’s were equipped with rear-looking sonar systems in a towed teardrop array, but that rearview system was more of a self-defense mechanism, a last-resort warning of torpedo attack, rather than a sophisticated fleet defense sonar.

  As the result of the poor deployment of the escort fleet’s antisubmarine-warfare equipment, six Mod II torpedoes sailed eastward undetected toward the hulls of the aircraft carriers.

  The first-launched weapon sailed under the bow of the center aircraft carrier. Its proximity sensors, tuned to the most sensitive mode, detected the hull magnetic-force anomaly almost immediately. The optic module saw darkness above. The blue laser easily saw the hull, so close that it was less than a half torpedo-length away.

  The three hull-proximity detectors faithfully sent their signals to the weapon computer software, where a series of hard and soft interlocks monitored and controlled the arming and ignition train of the explosives. The weapon computer followed its programmed logic, which directed it not to wait — there was no delay built in for this weapon as there was for the second unit. That way the first would detonate under the bow of the target and the second would detonate under the aft hull. A software “soft” contact closed, sending power to a physical contact that completed the battery circuit to the two low-explosive ignition canisters, one forward in the warhead zone and one aft. The canisters, receiving the spark of electricity, blew up, thereby igniting the secondary explosives, which were less sensitive but more powerful, located at the torpedo centerline at the forward and aft parts of the plasma warhead. The secondary explosive then detonated the forward and aft high-explosive, shaped charges. The explosion front expanded from the forward shaped charge heading aft and from the aft shaped charge heading forward; the two explosions compressed the warhead material in the center to several hundred atmospheres. The elevating temperatures and pressures of the explosion zones started the reaction required for plasma formation, a complex series of chemical containers vaporizing and adding components to the recipe at different timed stages of the detonation. The temperature and pressures soared as the explosion compression continued, bringing four masses of plasma igniter together into one critical mass. The plasma igniter exploded ratcheting the temperature and pressure even higher, though the skin of the torpedo remained intact at this point, the weapon still moving through the sea as its internals became a ball of flame.

  As the weapon internals reached tertiary ignition temperature, the components of the plasma fuel detonated, and plasma ignition commenced, almost instantaneously converting the mass energy of the warhead molecules into thermal energy. The central mass became a plasma, an ultradense molecular structure sending all molecules’ electrons into space in a single concentrated wave; then wave after wave of photons flashed outward as the plasma mass glowed. The ignition continued, the plasma volume increasing from mere cubic centimeters to a cubic meter, finally the plasma front erupted from the skin of the torpedo and consumed it in the growing plasma volume. The water around the torpedo was added to the plasma volume, growing from a cubic meter to over twenty cubic meters, the volume fed by the igniter material until it was completely consumed. The volume was now reaching hundreds of millions of degrees, hotter than the surface of the sun. The thermal energy was greater than the detonation of a half dozen old-fashioned hydrogen bombs.

  The plasma volume reached outward and upward, reaching the first molecules forming the hull of the aircraft carrier above. First the epoxy resin of the outer layer of paint, then the urethane intermediate coating, and the inorganic zinc primer, all those chemicals disassociated from their complex molecular structure and dissolved into atomic nuclei and electrons. The plasma front reached the next layer, the steel formed of carbon and iron atoms in a matrix called a solid phase, with an elongated grain structure formed by the rolling of the steel plates in the mill at a place called Bethlehem. The steel plate grains melted together from the intense heat of the approaching plasma, the iron and carbon swimming together in a volume of high-temperature suspension.

  The rising temperature excited the molecules to the point that they too joined the plasma.

  The plasma’s growth soon stopped, the intensely high temperatures unable to be sustained for more than a few microseconds. The cooler temperatures of the surrounding world drew the heat away by radiation, convection, and conduction until the hundreds of millions of degrees had become mere millions. The plasma volume — once at the boundary of the steel hull above, having eaten its way a meter and a half into the ship— collapsed. Though not hot enough to be a plasma, the remaining high temperature was still intensely hot, hotter than all phenomena except a fission-bomb explosion. The thermal energy of the former plasma boiled the water within a hundred meters into an intense volume of high-pressure steam. The shock wave from the steam and vaporized iron slammed upward into the hull. The incredibly high temperatures reached the hull remainder next, hot enough to change the steel to iron vapor. The molecules wanted to fly out into space from their incredibly high kinetic energy, but having nowhere to go because of the surrounding matrix of steel, this caused a soaring pressure wave that blasted through the ship.

  The heat, pressure, and blast effect propagated upward through higher-level decks of the ship’s hull, the solid metal continuing to vaporize and add to the pressure wave. The hull continued to disintegrate, the structural steel vaporizing as well as the steel of heavy equipment — catapult machinery, the anchors with all their chains and winch machinery. In addition to metal, there were other atoms in the advancing fireball — electrical cables, plastic insulation, more paint, vinyl flooring tiles, life jacket material, paper, computers, and flesh, the flesh of human beings who had been warehoused in the forward third of the hull in places called called berthing compartments. Row after row, columns and columns, of bunks housed men and women sleeping in the afternoon after having stood their watches through the night.

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sp; Some of the people were sitting at tables, playing cards, studying technical manuals, writing letters to wives and husbands and children who slept on the other side of the hemisphere.

  The people in the berthing compartments never became aware of the blast of the fireball reaching them.

  Their molecular structure was burned and vaporized long before their nerves had time to transmit sensations.

  Their brain matter disintegrated into basic elements in the next microseconds, with no time to record or react to the physical phenomenon of the high-temperature fireball.

  As the blast wave reached the upper deck, it no longer had the thermal energy to vaporize the molecules it encountered to their gaseous state. It had enough energy, however, to melt the metal atoms it encountered, and was still transforming water molecules to high-pressure, roaring steam. The temperature was still hundreds of thousands of degrees hotter than the blast wave of conventional explosives. The shock continued upward and aft, consuming the ship, the iron atoms melting from solid to liquid, now at a temperature that the iron and carbon combusted in the presence of the oxygen atoms of the air, the ship literally burning like the tip of a struck match. The blast moved on, reaching the upper deck of the ship and violently blowing the deck surface structure high into the sky. Some resolidified iron chunks tumbled end over end two kilometers in the air. The blast roared over the three dozen jets that had been tied down in a ready position, half of them F-22 Dynacorp fighter jets being prepared for the assault on the Asian continent to the west, the other half S-14 Blackboard twin-engine antisubmarine aircraft readied to take flight in the event of a submarine alert. In a flash these advanced jet planes became molten and burned aluminum and carbon fiber and burned plastic, their structure likewise blown thousands of meters skyward.

  The blast peeled the deck back and up. The ship just forward of the island vanished into what visually appeared to be an orange ball of intensely hot flames. The explosion age was now twenty milliseconds. Twenty thousand microseconds before, the ball of thermal energy had been contained in the body of a weapon called a Nagasaki II. Now the miraculous thundering sphere of white and orange heat blew farther aft toward the island, the forward surface of the tower above the formerly flat deck burning and disintegrating.