Unless ordered to testify under oath, the Norton personnel in question would probably have denied the name’s origin as a backronym, such linguistic manipulation having connotations of unprofessionalism in the industry.
Sea Bat 035 knew nothing of these things, and it cared not a bit what title it was called by. Like the other Unmanned Underwater Vehicles of its design series, the Sea Bat had no awareness of humans or their affairs. It was interested in only three things: the acoustic emanations of specific aquatic mammals, the movements and migratory patterns of those creatures through the ocean environment, and compliance with certain operational and maintenance related programming imperatives.
In configuration the UUV was a glider, cruising slowly through the sea on tapered wing-like foils that blended smoothly into the body of the hull form. It was dolphin-like in shape, partly to appear less threatening to the marine life it was built to study, and partly because the length-to-diameter ratio of 4.5:1 created minimal hydrodynamic drag (a lesson learned from the dolphins themselves).
Under the original production contract with NOAA, this particular series of Sea Bats had been configured to detect, approach, and follow acoustic emanations from members of the genus and species Balaenoptera musculus, more commonly known as blue whales. Each of the UUVs had carried a library of signatures containing frequency sets in the 10-40Hz range most often used for blue whale vocalizations.
For Sea Bat 035 and its brother units now swimming in the vicinity, the signature library had been overwritten with frequency patterns associated with a North Korean supercavitating submarine. The Sea Bats were not aware of this change, of course. They detected acoustic signals, compared them to target frequencies from the signature library, and acted as the situational response algorithms in their software dictated.
As far as the Sea Bats were concerned, anything emanating the proper target frequencies must be a blue whale. Their programming imperative was to move in close enough for easy observation.
So it was with Sea Bat 035. The UUV’s acoustic sensor package had detected two of the target frequencies. It made a gentle turn toward the axis of highest signal strength, and began its unhurried glide toward the source of the noise — wings pinioning in a slow-motion flap not unlike that of a penguin.
After fifteen minutes, the two target frequencies were joined by a third. Another few minutes of swimming brought a fourth frequency, and then a fifth. Sea Bat 035 glided on.
Eventually, the signal strength passed a critical threshold. The Sea Bat’s operational program instructed the UUV to turn aside, but that order was immediately countermanded by a higher priority command from the emergency recovery subroutine.
The turn-away command was ignored. Sea Bat 035 continued to close in silently and serenely on its “whale.”
The Sea Bat series gliders were designed for an operational lifespan of five years, and a maximum mission duration of six months.
Sea Bat 035’s lifespan was somewhat briefer than that. One hour, four minutes, and eleven seconds into its very first mission — at a distance of less than two feet from the “whale” it was tracking — the UUV satisfied the final arming conditions for the small (but significant) explosive charge carried in its belly.
Seven and a half pounds of plasticized pentaerythritol tetranitrate detonated with a force equivalent to ten M67 fragmentation grenades.
Sea Bat 035, which had not been designed with such capabilities in mind, was not expecting this abrupt and terminal change in its fortunes.
Neither was the “whale.”
CHAPTER 64
The explosion jolted Hwa Yong-mu awake. He lay in his hammock for a second, trying to figure out whether he had dreamed the earsplitting noise. Then the sound of shouting voices told him that the detonation had been real.
He rolled out of the cramped sleeping area, jammed his feet into his shoes, and hurried toward the control room. He pretended not to notice the clumps of hair left behind in the hammock.
When he reached the control room, his first officer, Lieutenant Po Hyun-su, was half out of the command chair, gesticulating toward an electrical junction box. “Cut the power!”
Two crewmen were struggling to stuff rags into the narrow space behind the electrical box, where rivulets of water could be seen coursing down the bulkhead.
It wasn’t much more than a trickle, but there shouldn’t have been any water at all. There was no piping in the control room, for this very reason. The only possible source was the sea itself: a penetration of the pressure hull. And that was not good.
“Shut off the circuit!” Po shouted. “Before you chon-noms electrocute yourselves!”
One of the crewman rushed to a breaker panel and did as ordered, locating the proper circuit and flipping the power switch to the off position. Part of the control room lighting went dark, along with two of the display screens.
Hwa Yong-mu caught Po’s eye. “Comrade Lieutenant! Make your report! What happened?”
“We don’t know, Comrade Captain. There was an explosion; I believe outside the hull. Perhaps we struck a mine.”
“A mine?”
“Just a thought, sir.”
Hwa Yong-mu gave the logical order. “All engines stop!”
If there was any chance that the explosion had been caused by a mine, he wasn’t going to risk hitting another one. Better to stay put and assess damage.
“Sir! All engines are stopped!”
Hwa turned toward the sonar station. “Report all contacts!”
“Comrade Captain, we are tracking two fishing boats at medium to long range, bearing three-zero-four and three-three-seven degrees. Also, we have an oil platform at long range, bearing zero six zero, and a long-range merchant ship bearing one-five-two.”
“Close aboard contacts?”
“None, sir.”
By now, another pair of crewman had arrived with tools and a patching kit. They began unbolting the electrical box from the bulkhead.
Hwa motioned for Po to vacate the command chair. “Form an inspection team, Comrade Lieutenant. We need to be certain that we’re not taking on water anywhere else.”
Po acknowledged the order and headed aft.
Hwa settled into the chair. Wouldn’t a mine have done more damage? Maybe this hadn’t been a mine. Perhaps it was a stress crack in a weld, brought on by water pressure.
That couldn’t be right; the Steel Wind was only sixty meters down. He did a quick mental calculation. The water pressure at this depth shouldn’t be much more than 600 kilopascals. Not enough to cause hull failure. Unless this was an aftereffect of damage done by an earlier dive, or possibly the structural strain of operating in supercavitation mode.
Besides, he had distinctly heard an explosion. Not the crack of a failing weld or a buckling hull plate. Quite definitely an explosion.
And the source did not appear to be inside of the hull. The only other possible source was outside of the hull, which would seem to indicate either a mine or a torpedo. But sonar had detected no hydrophone effects from the high speed propellers of a torpedo, and the blast yield would have been much larger for any torpedo warhead or mine.
Which brought him back around the circle again. Not a mine, or a torpedo, or a mechanical hull defect. What did that leave?