The nuclear submarine Charlotte had been stationed in the Arctic Ocean for five days now. Its presence here was highly classified.
A Los Angeles‑class sub, the Charlotte was designed to listen and not be heard. Its forty‑two tons of turbine engines were suspended on springs to dampen any vibration they might cause. Despite its requirement for stealth, the LA‑class sub had one of the largest footprints of any reconnaissance sub in the water. Stretching more than 360 feet from nose to stern, the hull, if placed on an NFL football field, would crush both goalposts and then some. Seven times the length of the U.S. Navys first Holland‑class submarine, the Charlotte displaced 6,927 tons of water when fully submerged and could cruise at an astounding thirty‑five knots.
The vessels normal cruising depth was just below the thermocline, a natural temperature gradient that distorted sonar reflections from above and made the sub invisible to surface radar. With a crew of 148 and max dive depth of over fifteen hundred feet, the vessel represented the state‑of‑the‑art submersible and was the oceanic workhorse of the United States Navy. Its evaporative electrolysis oxygenation system, two nuclear reactors, and engineered provisions gave it the ability to circumnavigate the globe twenty‑one times without surfacing. Human waste from the crew, as on most cruise ships, was compressed into sixty‑pound blocks and ejected into the ocean‑the huge bricks of feces jokingly referred to as whale turds.
The technician sitting at the oscillator screen in the sonar room was one of the best in the world. His mind was a dictionary of sounds and waveforms. He could distinguish between the sounds of several dozen Russian submarine propellers, hundreds of marine animals, and even pinpoint underwater volcanoes as far away as Japan.
At the moment, however, he was listening to a dull, repetitive echo. The sound, although easily distinguishable, was most unexpected.
You arent going to believe whats coming through my listening cans, he said to his catalog assistant, handing over the headphones.
His assistant donned the headphones, an incredulous look crossing his face. My God. Its clear as day. What do we do?
The sonar man was already on the phone to the captain.
When the submarines captain arrived in the sonar room, the technician piped a live sonar feed over a small set of speakers.
The captain listened, expressionless.
THUD. THUD. THUD.
THUD . . . THUD . . . THUD . . .
THUD. THUD. THUD.
Slower. Slower. The pattern was becoming looser. More and more faint.
What are the coordinates? the captain demanded.
The technician cleared his throat. Actually, sir, its coming from the surface, about three miles to our starboard.