The next day she did it again, dive towards the shore, get ashore, take off the suit. He had her do it twice with a black plastic bag filling her mask, simulating a night dive. Then twice more in the dark. They surfaced by the boat that night. “Ok May, it’s oh three hundred hours, get your equipment aboard, you’re as good as you’re going to be.”
“Good enough?”
“You’ll do.” I hope so, thought Innes, he knew they could face anything where they were going. Carrying out a nighttime underwater Infil in hostile territory, it didn’t get any worse than that. It’d be better not to tell her about the dangers they’d confront.
“TRIM FORE AND AFT FOR ascent. Up bubble ten, come to periscope depth.”
“Aye sir up ten for periscope depth.”
The deck rose to the bow and levelled out. Nathan checked the depth indicator.
“Sonar report.”
Benson listened and watched what they called his guessing screen. Another rating had secured by duct tape a cup with tea leaves in it. Some days it would be a crystal ball or animal entrails from the galley.
“Commercial traffic only sir. Nothing out of the expected range.”
“Kaminski get me a satellite fix when I raise the scope.”
“Sir.” Nathan pressed buttons to raise the photonic mast and did a full 360 sweep and retracted the periscope.
He sat at his monitor and panned around the sweep, it was in night vision mode and you could see the river estuary Cardinal lights, showing safe passage channels in and out of the port. To seaward were ships lights. A zoom in on each showed they were cargo traffic only.
“Kaminski. Sat position fix.”
“Sir, on the board now sir. We are two point three miles off Shuikou port. Yezi Island should be visible at 240 degrees behind the breakwater.” Nathan confirmed the view on the monitor.
“I have Yezi in view.” The port was just 30 miles from Hainan, China’s main submarine port and home of major surface units. It had been expanded in recent years and could offer facilities and birthing to ships of Destroyer size on down. The river led eventually to the town of Lingshui.
“Left one third rudder, speed six knots.” Nathan raised the mast again and took a partial scan to the west.
“Hold your course.” He waited four minutes and passed, he raised the mast again and swept west.
“All stop.”
Nathan walked back aft down the main companionway. Innes and May Hsin stood wearing diving suits and full rebreathers.
“All set, Innes?”
“Aye sir,” replied Innes. May looked unsurely, even frightened but nodded.
“You’re about one eighty yards from the entrance. The bearing to datum two is two three five degrees.” Innes set his compass bezel to the bearing.
“Off you go, and good luck.”
Innes opened the lower hatch and climbed up, May followed. The seaman to one side helped them both up into the sail, the hatch was sealed and wheeled shut. Two taps followed by two more was the signal. The rating opened a valve to let seawater into the chamber.
INNES AND MAY SWITCHED on their helmet lights, the red light filling the chamber with a dull glow. They were already waist deep in the rising seawater. Equipment checks had already been carried out in the boat’s main companionway. Innes could see May’s hands checking and rechecking the valve settings. He knew it was a sign of fear, check and recheck over again. He held her hand and shook it reassuringly, looked into her mask and smiled.
The chamber filled, the water level rose to cover their masks, then finally, it was full. Innes made an OK sign and showed it to May, she nodded and returned the sign. He reached up and turned the wheel, then stepped up a couple of rungs, reached back and patted her head. Innes lifted the hatch. Outside was a deep black void. Innes swam out into it, May followed, the two of them were now kneeling in the sail. He gave her an OK sign, she returned it with little enthusiasm. She checked her valve settings again. Innes patted them gave her the OK. He took a bearing and kicked off. She followed. Their buoyancy was slightly negative so they drifted down to the seabed. It was silty, there was a mass of filter feeders and starfish. Some were thin, kelp like green fronds waved to and fro. They were everywhere, he knew they’d be feeding off the outflow from the river. Natural and human waste, discarded food would all pass this way. Innes checked the depth, 80 feet. The world was filled by the sound of their breathing and the hiss and pop of the feed and return valves of the Poseidon SE7ENM rebreathers.
The rebreathers they wore were a high-tech triumph. They were a fully closed circuit and gave no bubbles off, they re-used their breath and removed carbon dioxide. Electronics made sure the divers always got the right mixture of gas for their depth; the required Oxygen level was lower when they went deeper. All this gave the divers the right gas for the depth they found themselves at, the least gas for the maintenance of life and the lowest chance of DCS; decompression sickness, or the bends. May shouldered the rebreather. Inside the shell on the divers’ backs, was a large cylinder to the left and plastic tube of some powder substance with a smaller cylinder below it.
Innes checked the digital readout, it checked the two cylinders carefully. In the larger tank was the diluent, Trimix. Helium, oxygen and nitrogen. The small tank held oxygen.
Innes remembered his training. Using a diluent sounded exotic. A diluent was nothing exotic, a non-diver breathes a diluent: the nitrogen in the air. We all breath diluent all day and night.
Oxygen was added to the trimix when told to by the computer. As well as breathing, He knew the mix provides buoyancy gas to the bags on the diver’s chest. This gas is also breathed in and out. The powder scrubbed out the carbon dioxide.
Innes knew that May and him were in their equipment’s hands. Rebreathers provided them with a much extended dive time and depth, and of course no bubbles; ideal for a covert Infil of an enemy’s harbour or other facilities.
He ran his hands over the tank on his chest. They each wore a seven litre bail out tank with its own breathing regulator. This was just in case the rebreather failed. It was filled with Nitrox thirty six; that is thirty six percent oxygen, sixty four percent nitrogen, so reducing the decompression time. He decided it was time to attach a buddy line, he didn’t like them, but better now than when you didn’t have to time. He clipped May to him on a three yards long line. Innes followed the compass upriver, not really seeing where you were was one of the worst parts of it. Trust your instruments, total trust, you’ve nothing else. The most unreliable thing down there was that lump of grey matter in your head. Clever enough to figure out how to get through and survive that black void, but not clever enough to get through by itself. Innes knew that they must be more than half a mile up the Lingshui river by now. He looked back at her, May had settled now. She couldn’t do anything about it, so she was just getting on with it. Finning away through the blackness, heading for wherever he’d take her. Innes knew he couldn’t do that, he had to know where he was and what his fall back would be. He knew she was so far out of her depth, so to speak, she just had to follow him.
He smiled, there were more boring ways to make a living. When he signed up he didn’t expect he’d be swimming in the blackness of a Chinese river on an Infil mission with a hot Chinese br…No, hot Taiwanese broad. Innes gave his digital instrument the once over, depth, no stop time, PPO2, gas mix. Ok, he turned to check May’s instruments and gave her the OK then turned and carried on.
It wasn’t loud; at first. Then it grew, a deep inexorable throb. A thrumming sound. Innes knew what it was, a ship or ships heading their way. He knew they wouldn’t draw more than seven or so yards, so they were deep enough down here. The sound grew louder, it was advancing. He heard something unusual, something rumbling. He turned to May pointed to his ears, cupped them and gave her the ok sign. She nodded. He turned back and swam on. He wasn’t ok at all, what the hell was it? Innes could feel it now a thrum, thrum, thrum with the rumbling noise, he could feel the vibration.