Early in the pre-dawn hours, Bastian was up in the lookout ring when the sky began to lighten in the east, graying out the stars in that direction and creating an echo of light on the black disk of the ocean. When Bastian could see his hands in the gloom in front of him, he climbed down to the bridge and, cupping one hand around his mouth, shouted down to the control room that it might be time to dive.
Percy climbed up to join Bastian on the bridge and looked around for a few minutes. She took some long breaths — the last of the fresh air before the next twelve hours or so below deck — and then told Bastian to follow her back down into the sub.
They buttoned up the Prospect and, when all the hatches showed green lights on the board in the control room, they shut down the diesels and dove the boat to fifty meters. After fixing their position earlier in the evening, Hemi slept his three hours, and then returned immediately to the control room. Now that they were submerged again, he wanted to take the boat in a new direction as a precaution against the small chance that anyone had been tracking their course on the surface without their awareness. With the cargo they were hauling, Hemi felt there was no reason not to use every stealth maneuver they had.
After they had leveled off, he had them bring the boat hard about to starboard. This was backtracking a bit, but they were now aimed directly at the rendezvous point for the Gnat, which they would reach in another two hours at their current speed.
Those two hours remained nearly silent and uneventful. Everyone had low early-morning energy and no one felt like much of a conversationalist after a long night with short sleep. Though the social situation was improved by Gregory bringing up the first pot of coffee and passing around tin mugs to the crew in the sonar compartment and the control room.
They cruised to the rendezvous point, and then came up to thirty meters of depth. They shut down the electric motors entirely, and Hemi trimmed the boat until it sat hovering perfectly still and silent in the water.
Cassandra was just waking up from her sleep rotation, and groggily making her way from the crew quarters to the sonar compartment where she found Hemi. He handed her a tin cup full of sweetened black coffee.
“Time to get back on sonar Cassandra. We have reached the spot where we are supposed to rendezvous with Shakes. I need you to listen for his boat. It is quite a small boat, so it may be challenging to hear. But since we have got the Prospect completely shut down you will have total silence. If you hear Shakes — or anything else in the water — come get me. I will be in the galley. The rest of the crew is going on break while there is nothing to do, so it is all you right now.”
“That makes this sound important… You trust me with this?”
“It is good practice for you, and the worst that could happen is you miss him and we are a little delayed in the rendezvous. I would be happier if we got moving again soon though, so…try not to miss him if he goes past.”
“OK, Hemi.” Cassandra sat down at the sonar rig, put the headphones on, and took a sip of her coffee before passing the mics around in a full circle to get settled and oriented.
Hemi went off to the galley with his clipboard and notes, and the rest of the crew hit the racks to catch up on much-needed sleep. The Prospect was left dark and absolutely silent.
Cassandra turned the directional control of the mics slowly around. She completed another full circle, and then came back the other way. Her eyes closed and she could see the sounds in the water coming towards the Prospect. The water had slightly different qualities in different directions, so after a few times around she could tell generally which way the microphones were pointing without looking at the directional indicator. When they were forward towards the bow, she could hear the bilge water sloshing in the lowest parts of the ship. Towards the stern, she could hear clearly without the annoying interruption of the propeller sound that was always in that direction while the electric motors were running.
The Prospect was currently at its absolute maximum sonar listening capacity, but there was nothing out there. The ocean was completely empty in every direction. Cassandra focused her mind and kept it out in the water. Every time she felt some subject other than sonar intruding on her consciousness, she took a deep breath and forced her mind back out into the water.
It was incredibly tiring work.
Two hours later, there had still been no sign of Shakes. Percy could never sleep for long, and so was soon back in the control room with a cup of coffee from the galley, smoking and making small adjustments to the trim of the boat. Each of these adjustments was accompanied by a brief rush of water or air through the piping of the ship. And each time this happened Cassandra got completely distracted for a few frustrating moments. Cassandra did not yet realize that the sonar operator could, in some instances, have some authority over even the captain on a submarine and request silence be maintained.
Another hour went by. Cassandra thought she was starting to crack. She considered asking Hemi to take over. She was worried that somehow Shakes had sneaked past her in his little sub. That she had missed him and screwed up her first real job. Rationally, she knew that was unlikely though. She pushed herself to keep listening to the silence.
Then, far off their port side, she heard an engine in the water. It was not like the other sea craft she had heard thus far in her limited experience on sonar. It had a continuous popping sound, like a machine gun being fired off in the distance, accompanied by a low-frequency roar.
“Captain Percy!” Cassandra called up to the control room where Percy still sat fiddling with the controls to her boat. “I hear something.”
Percy slid down the ladder and picked up the second sonar headset and put it on. Cassandra rolled the mics back and forth across the direction of the contact, and settled them in on the strongest signal.
“Is that Captain Shakes?” Cassandra asked doubtfully.
Stolen story; please report.
“That can’t be fucking Shakes. It sounds like a supertanker or an aircraft carrier or something. Go get Hemi. I think he should hear this.”
Cassandra went off to the galley, leaving Percy listening to the contact. She came back with Hemi, who held a tin cup with the dregs of cold coffee in the bottom. He slipped the headphones on and stood there, his coffee cup tilting around his fingers, staring at the gauges on the sonar and watching them bobble up and down. He flipped some filters on and listened again.
“Well,” Hemi said, “that is strange. It does sound like a tanker or something big just from sheer volume. But it is moving very fast, too fast for a big ship…” He paused listening again. “It is closer now, and I can hear the prop revolutions… The frequencies are all wrong. The prop is spinning too fast, and sounds small, not like a big ship screw.”
“Shakes was planning to modify the Gnat to be louder — you think that could be what his boat sounds like now?” Percy asked.
“If that is Shakes, the job has been overdone…”
“Really? You think it’s fuckin’ possible Shakes overdid it, do you?” Percy rolled her eyes. “Maybe instead of the sound of the Gnat masquerading for the Prospect, the Gnat will just drown out everything in a ten-mile radius.”
“I just…” Hemi started, “just cannot believe that such a small boat could…” he paused listening again. “No, I am more sure of it now. The more detail I can hear, the more it makes sense that it is a very, very loud, small boat, not a big ship. Though he does have it tuned so low that from a distance anyone who is not skilled on sonar might easily be fooled into thinking the contact is displacing an enormous amount of water. Good job with the identification, Cassandra.”
Cassandra held onto a large and genuine smile.
“OK then. So now what do we do?” asked Percy. “If we were on the surface, I’d try to raise him on the radio. But I arranged with Shakes to rendezvous at depth, so no one sees us. I’d hate to blow our cover by surfacing now.”
“I do not know,” said Hemi. “The contact is well out of range of ship-to-ship. I would guess something like still twenty nautical miles off or so. We could hit it with active.”
“If it turns out you’re wrong and the contact is actually that sub with the ram tearing its way towards us, then an active ping will be like knocking on their hatch and telling them exactly where we are.” Percy paused. “We have the advantage of being completely hidden at the moment. I hate to just hand that away.”
Hemi shrugged. “That is why I leave the decision to you.”
Percy considered her options. “You are fairly certain it’s Shakes?” she asked Hemi.
“I am fairly certain that contact is not the big ship it initially sounded like,” said Hemi.
“Fuck it. Ping it.”
“OK. Cassandra, remember I mentioned ‘active’ sonar during your training session? I am going to use that now. Follow what I do.” He powered up the active sonar unit. “Passive sonar is like listening quietly in a dark room to figure out where other people might be standing. Active sonar is like quickly turning a bright light on and then off again so you can see the exact location of the people in the room. The principles behind it are much more sophisticated than passive. But it is easy enough to operate.” He set the direction indicator to point towards the contact. “Push the PING button, Cassandra.”
She held her small finger out flat, so as not to let her long fingernail get in the way, and crushed the button home. Even without the sonar headsets they could hear the smooth round ringing sound of the ping echo through the hull and spread out into the water around them. A few seconds later the active unit calculated and displayed the range and direction to the contact.
“The active sonar figures out precisely where your contact is by calculating how long it takes for that ping sound to bounce back from the target,” Hemi said, pointing to the readout on the active sonar unit. “That is useful if you have to do something like aim and fire a torpedo. But since the Prospect does not have torpedoes, we do not often have reason to use it.”
“The active ping also tells the target exactly where we are,” added Percy. “Normally, we would not want to do that — never use the active sonar without an explicit instruction from me or Hemi — but assuming this contact is Shakes…,” she looked at Hemi, “then we just deliberately let them know exactly where we are by hitting them with that active ping.”
“We shall see what the contact does now,” said Hemi, putting the sonar headset back on.
Within a minute of the Prospect’s ping, the contact went silent.
“They’re gone?” Cassandra asked, still listening to the other headset.
“They have shut down their engine,” Hemi said, “which does not tell us anything.”
“Well, how the fuck were they supposed to respond?” Percy asked Hemi.
“Can he just ping us back?” asked Cassandra.
“I am not sure the Gnat has an active sonar system like that,” said Hemi. “We could ping them again? It would let them know we are not going anywhere.” He looked over at Percy.
“And then what? What’s the full fuckin’ plan here Hemi?” she asked.
“Well, without surfacing, I think we wait until he moves into ship-to-ship range. Then we can confirm it is Shakes over ship-to-ship radio.”
“A quarter of a nautical mile? If it’s someone who wants to do unpleasant things to us instead of Shakes, that’s awfully fucking close.”
“If they want to do unpleasant things, they are likely to begin long before reaching ship-to-ship range,” said Hemi. “I advise we ping them again. If the contact does anything that seems suspicious, we will move off from this spot — quietly.”
“…Alright,” said Percy. “Fuckin’ ping ’em again. What do I care, it’s just my boat and all our lives.”
Hemi caught Cassandra’s eye and pointed to the PING button. She reached out and pressed it again. Another resonant ping left the Prospect and soared through the water. The range and direction displayed on the active sonar unit.
“See, Cassandra, it was like they were invisible while they were being silent, but bouncing the ping off them let us know they are still there. …And they know we are still here.”
Cassandra nodded with one hand on an earpiece. She listened quietly for a minute. Then: “I think I hear something.”
Hemi listened closely. “OK, the contact is running on electric motor now. And I can tell by the pitch that it’s definitely a small craft moving quickly… towards us.” Hemi listened for a moment longer. “It is definitely the Gnat, I recognize it now.”
“Thank fuckin’ hell,” said Percy. “That was ridiculous, Hemi. We’ve got to work out a better way of communicating with the Gnat if we’re going to keep working with that guy. We can’t be pinging every tanker that goes over us hoping it’s actually our tiny submarine friend.”
“I’ll talk to Shakes about it when we get him on board,” said Hemi.