Piranha: Firing Point

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 name.

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.