Tropical Terror

17

A half hour after the sweep by the big ship began, a sailor came to tell Murdock he was wanted in the radio room.

“CINCPAC is calling for you,” the seaman said. “We don’t get many messages from the top man in the Pacific.”

Murdock took the handset and responded.

“Murdock here, sir.”

“Yes. Good. Thought you would be on board the Chief. We’ve had some reaction from Admiral Magruder on the Jefferson. He’s had some of his antisub choppers on a search pattern around the waters off Kaneohe Bay. Says there’s a chance that the mini-sub was brought in by a regular Chinese sub latched to the deck. Then when they got into the shallow water of the bay, or near it, they sent the little guy in to look for the bomb.”

“Yes, sounds like a good possibility.”

“Now that the mini-sub is gone, the Chinese will have to use some other tactic. Chances are that the regular sub will come into the bay hunting the bomb, or it will send in divers or small boats. Magruder wanted you to be aware of this possibility and figured you might have some ideas.”

“Yes, sir. Those sub-killing torpedoes are the best idea. Did the admiral say that they had any indications that there was a sub off the coast?”

“From their searches they have had some readings, but they fade out too fast. He says definitely there is at least one Chinese sub in this area, but they aren’t sure exactly where.”

“Sir, there’s been some talk about the bomb threat as being a hoax. Any thinking on that?”

“We’ve worked it over a dozen times. The radiation we found where the bomb package had been could have been planted, or allowed to leak from some other radioactive material in that big box. Then, on the other hand, they have done a lot of work to plant the thing and move it. Feeling is here that we have to treat it as a real threat until somebody finds it and proves it’s not a nuke.”

“We’ll go on that assumption, Admiral. Anything else?”

“Do what you can for us, Murdock. All we can ask.”

“Do our best, Admiral Bennington.”

They signed off and Murdock went back to the compartment where they had the readout.

“Nothing so far,” the ship’s captain told Murdock. “We’re still working in what we call the hot zone. We could pick it up any minute if it’s still there.”

“Kind of hard to move that beer truck and the big box without some divers and a good tugboat,” Murdock said. “Divers couldn’t do it alone.” They watched the readout.

A half hour later Murdock had a question. “Commander, if you needed to drop a package into the bay here and intended to come back for it, how would you do the job?”

“How? Equipment?”

“That and anything else that would help you locate the package.”

“I don’t know. A marker buoy would be good, but then anyone could find it. Maybe put a sonobuoy on it activated, then locate it with a line of sonobuoys.”

“I thought they picked up signals for detecting subs. Could one sonobuoy find another one?”

“I don’t know. I never tried it.”

“How else could you mark a spot in the ocean and come back to it?”

“A radioactive leak?”

“It would get spread all over the place and not tell your Geiger counter where the leak came from.”

Commander Lawson shook his head. “I think you have something there, Commander. Just what the clue is I don’t know. If I wanted to drop something in the bay and come back for it, I’d mark it somehow, at least take its precise location with a mugger.”

“So how was that Chinese mini-sub going to find the bomb?” Murdock asked.

Lam had been listening to the talk. “Skipper, what about those things they have built into airplanes that send out a signal when they go down? You know, that emergency radio signal that can be followed to find the crash site.”

Murdock grinned. “A transponder. Yeah. It can work on radar, radio, or sonar. Most of them can start transmitting automatically in a crash, or they can be set to respond to an incoming signal, then send out a preprogrammed signal that can be tracked right back to the source.”

“You suppose the Chinese slapped a transponder on that bomb before they dropped it in the drink?” Commander Lawson asked.

“It’s a possibility. What can we lose by trying? Only what would it be on? Radio, radar, or sonar?”

“Sonar,” Lam said.

Commander Lawson frowned. “My field,” he said. “How do we know what power or frequency we would need to activate the transducer to respond to our signal?”

“We don’t. But what about some common ones. Would the Chinese build their own or buy them from us through some third party? Let’s assume they bought the transponders from some boat maker who put them into his pleasure crafts. What kind would that be and what power would it take to contact it?”

Commander Lawson nodded. “Let me get with an expert on sonar and we’ll see what we can do. We do have an array that we can put in the water and tow to send out a narrow-band search signal, or we can send out a wide band search signal. Give me a half hour.”

Murdock tried to remember all he could about sonar. The term came from SOund NAvigation Ranging, SONAR. By constant use it had dropped its acronym capitals and become sonar. It is a method for locating and detecting objects submerged in the water by means of echolocation.

It uses the transmission and reflection of pulse energy as the basis of operation. But the detection ranges for both military and civilian sonar go from one hundred meters to one thousand meters. Wavelengths for acoustic signals go from 0.5 centimeters to thirty centimeters. That corresponds to frequencies of three hundred kilohertz and five kilohertz.

Right, but what frequency would the Chinese use? Murdock figured he would need that exact frequency to activate a transponder on the bomb and get it to send out a signal that they could home in on.

They could get the frequencies used on airliners. That would be a standard that the Chinese might have picked up on. No, that would be radio. Sonar, they needed sonar frequencies. Maybe the transponders used on big yachts in case of trouble. Yes, that might be getting somewhere.

The same radioman came up and motioned to Murdock.

“Commander, you’re needed in the radio shack again. Right away.”

“CINCPAC?”

“Yes, I think so, sir.”

Murdock took the handset and reported in.

“Magruder tells me that they have had more indications of that Chinese sub. Last contact was about five miles offshore directly north of Kaneohe Bay. Evidence is that the sub is moving your way.”

“Admiral, we’ve been doing some brainstorming here and have about decided that the bomb could have some kind of a transponder on it. A sonar unit of some kind. Our thought is that the Chinese left the bomb here with a response transponder, so they could walk down a beam and find it when they wanted it, when it was safe to come and get it.”

“Which would be at night.”

“Exactly. Sub captains don’t like a hundred feet of water to crawl around in. The wide shelf here around the island is about a hundred feet for a long way out. That’s poison to a sub.”

“Unless they have another mini-sub on board that could tow the bomb out of there.”

“Doubt it, Admiral.”

“Me too.”

“The Navy choppers going to try to follow the sub in and nail it here?”

“We don’t know. This sub seems to have some tactic to become invisible. Working in and out of the thermal layer, I’d imagine. We’ll keep you informed.

“Murdock, say the minesweeper finds the bomb, can you go down and get it? The sweeper doesn’t have divers. Can you work down to, say, a hundred feet?”

“Not with any safety, Admiral. Our closed rebreathers are generally not good much below thirty feet for any length of time. We could program them with nitrox mixture of oxygen and nitrogen to work the Draegrs down to a hundred feet. But we don’t have the goods with us. If we could get some regular open-system SCUBA outfits, our men can go down over a hundred feet to fasten cables on that truck if we find it.”

“I’ll see that four sets of gear are flown over there tonight. Keep us informed. Now, what about that damn Chinese sub?”

“Let’s hope that the antisub guys can nail it before it gets to the bay. It could slip in during darkness and get the bomb, only I don’t know how they would haul it out to deep water.”

“We’ll watch for them. Any late word on the sub?”

“No, but I’ll let you know if it gets any closer.”

“I’ll get my men alerted,” said the admiral. “If that sub comes in near the point, we might be able to spot it and trail it somehow.”

“Good hunting,” said Murdock.

He held the mike a moment, then gave it to the seaman and went to find the captain.

Ten minutes later the three SEALs were on shore talking to the rest of the men.

“So, that brings you guys up to date,” Murdock said. “You know everything about it that I do. The commander is working on the transponder idea, trying to get the right frequency. In the meantime we’re on sub alert. Anybody remember how to disable a sub that’s in operation?”

“Blow his fucking conning tower off,” Jefferson said.

“Good idea, but we won’t have that much C-5. How else?”

“If she’s stopped you could blow off her propeller,” Bradford said.

“But she’s moving,” Murdock prompted. He looked around. Nobody spoke up. “Okay, I don’t know what the Navy calls them, but they are the exterior control panels that make the sub move up or down. Like a wing flap on a plane. If you jam these in one position with a charge, the sub is not able to control up or down direction and can’t repair the damage without surfacing. It’s a chance. If the periscope is up, you can always blow it off with a quarter-pound.”

“So, we’re going sub hunting?” Ostercamp asked.

“Just like deer hunting,” Holt said. “Only a bigger target.”

“When do we go for a swim?” someone asked.

“Not until we’re pretty sure that the fish is going to motor into our pool,” Dobler said. “Let’s get some shut-eye so we’ll be ready to go. The time is now 22l3. Any questions?”

“They going to figure out the right megahertz to make that transponder talk, if there is one out there?” Mahanani asked.

“We damn well hope so,” Murdock said. “Holt, let’s play radio.”

Murdock tried TAC Two, and caught the chopper pilots chasing the sub.

“Sunnyside One here. We’ve had two good strong contacts, then they fade out. He’s working closer to shore and near as we can tell, we’re still north and some west of that north point on Kaneohe Bay.”

“That’s a Roger, Sunnyside One. Keep at him.”

Murdock triggered the send mike button. “Sunnyside One, this is Murdock on Kualoa Point. How far from us are you?”

“Murdock, yes. Estimate about three miles. He seems to be motoring your way at about eight knots. But he’s doing a lot of thermal-layer work to confuse us.”

“Hope you can nail him before he gets here, Sunnyside.”

“Kind of what we had in mind. Watch for us. Sunnyside out.”

Murdock looked around in the darkness at his men. “We’ll want to go out fully armed and with explosives and detonators. If some of you don’t have them standard, share so every man has at least one charge. We don’t know what we might meet out there tonight. I hope like hell we meet something.”

The SEALs used small flashlights to check their equipment, then double-check a buddy. With that done, half of them crawled into the Humvees to get out of the soft breeze that had sprung up with sundown. Most of their cammies had dried out, but inside they were still damp. They were used to it. Better than walking around all day in a wet suit. Here the water was like a bathtub.

Murdock used the SATCOM and called the Chief. The radioman brought in the captain.

“Nothing so far on the scanners, Murdock. Been talking to some friends about that transponder idea. We’ve narrowed down the possible kilohertz bands to ten. It should be in that range. We’re in the process of getting a towed array ready to put in the water. It will be a relatively narrow band, but we can do it at the same time we’re working the sweep for the metal below. Once we get it functioning, we’ll send on a band for fifteen seconds. If no response, we’ll shift to the next band. Slow and painful, but it could produce results. Oh, you might have heard a chopper drop in on us a few minutes ago. We have a package for you with complete SCUBA gear and filled air tanks for four.”

“Good. If we get lucky and find the bomb, the tanks are for deep dives to hook on some cables. I assume you can winch up the prize if we find it?”

“No trouble, Commander. Easy. First we find it. Hear that sub is still headed this way.”

“True. We’ll swim with it if it gets inside the bay.”

They signed off and Murdock tried to relax. He had never tried to attack an active submarine before. Any charge big enough to do damage to the sub would also cause serious damage to any SEAL in the water close to it. The concussion would be devastating. But how could they signal the men to get their heads out of the water if one of them planted a bomb on the sub and pushed the timer? He had no idea.

Murdock frowned and looked to the west. He heard something. Then it came through, the whup, whup of a big helicopter. That would be the sub-hunter choppers. Maybe the same kind they had seen before that killed the mini-sub. How many? Two? He kept listening. Lam came over and pointed to the west, and Murdock nodded.

“If they do come in, hope it’s near the point up here,” Lam said. “Make it a hell of a lot more convenient.”

For ten minutes the sound of the helicopters faded in and out. Then it came stronger. The SATCOM, which Murdock had left set up to receive on TAC Two, came to life.

“Hey, Murdock. Looks like you’re going to have company. We can’t get a good enough fix on this one to fire. We tried one shot but had no results. It’s definitely heading into the shallows there around the point of the bay. Maybe a quarter of a mile or so south of you. Our cap says turn it over to you. Good luck. We’re low on juice and going back to Home Base.”

“Roger that, Sunnyside. You say they were maybe a quarter of a mile off the point when they enter the bay?”

“Just a guess. The sub was heading back toward us last hit. I’d figure no more than a quarter or maybe a half mile off the point southwest. You’ve got the con, Murdock.”

Murdock closed down the set and yelled at his men. “On your feet, ladies, we’re going for a swim, and we don’t want to be late for the party.”