It was a strange disconnect of sight, sound, and feel. The ship hardly shuddered at all when the first column of water leaped skyward. The noise was unmistakably real, and, coming without warning, it made Sanchez jump on the port-after corner of the island. His initial impression was that it hadn't been all that bad a deal, that maybe the fish had exploded in Johnnie Reb's wake. He was wrong.

The Japanese version of the Mark 50 had a small warhead, only sixty kilograms, but it was a shaped charge, and the first of them exploded on the boss of number-two propeller, the inboard postside shaft. The shock immediately ripped three of the screw's five blades off, unbalancing a propeller now turning at a hundred-thirty RPM. The physical forces involved were immense, and tore open the shaft fittings and the skegs that held the entire propulsion system in place. In a moment the aftermost portion of the shaft alley was flooded, and water started entering the ship through her most vulnerable point. What happened forward was even worse.

Like most large warships, John Stennis was steam-powered. In her case two nuclear reactors generated power by boiling water directly. That steam went into a heat exchanger where other water was boiled (but not made radioactive as a result) and piped aft to a high-pressure turbine. The steam hit the turbine blades, causing them to turn much like the vanes of a windmill, which is all the turbine really was; the steam was then piped aft to a low-pressure turbine to make use of the residual energy. The turbines had efficient turning rates, far faster than the propeller could attain, however, and to lower the shaft speed to something the ship could really use, there was a set of reduction gears, essentially a shipboard version of an automobile transmission, located between them. The finely machined barrel-shaped wheels in that bit of marine hardware were the most delicate element of the ship's drivetrain, and the blast energy from the warhead had traveled straight up the shaft, jamming the wheels in a manner that they were not designed to absorb. The added asymmetrical writhing of the unbalanced shaft rapidly completed the destruction of the entire Number Two drivetrain. Sailors were leaping from their feet with the noise even before the second warhead struck, on Number Three.

That explosion was on the outer edge of the starboard-inboard propeller, and the collateral damage took half a blade off Number Four. Damage to Number Three was identical with Number Two. Number Four was luckier. This engine-room crew threw the steam controls to reverse with the first hint of vibration. Poppet valves opened at once, hitting the astern-drive blades and stopping the shaft before the damage got as far as the reduction gears, just in time for the third torpedo to complete the destruction of the starboard-outboard prop.