Underwater, running out of air...

When I'm diving deep I always glance up to the surface. Sometimes, as deep as fifty metres, you can still see it, maybe even the boat awaiting you. But often or not, you can't. And the thought occurs to me, what if I were to run out of air, right now? Could I make it?

You can increase the danger by going inside a wreck at depth. Now, if you run out of air, you are already inside a steel mausoleum, and have to find your way out before you can begin to ascend.

The one time this almost happened to me was in the Isles of Scilly, off the Cornish coast. My buddy and I were inside a wreck, and I'd tied a line to the entrance/exit, so we could find our way out. It was about 40 metres deep. At a certain point, we both checked our air and decided we should head out and then back to the surface. But as I began reeling the line back in, it came too easily, and we both realized the unthinkable. The line had either been untied or had been cut. We were well inside the wreck, and I hadn't counted the twists and turns to get into its bowels. Our air was burning nicely at that depth, now aided by an adrenaline kick as we realized our predicament.

I stopped reeling the line in, and we simply followed it as far as we could. Luckily it got us close to the outside, and dim daylight guided us the rest of the way. I never found out who had untied the line or why. To this day, I prefer to think it was by accident.

I used the memory of this dive when I wrote the following scene for 66 Metres. In this part of the book, Jake has finally found the device that a range of killers are racing to find, the Rose, but is running out of air, and is beginning to suffer narcosis. Two Navy SEALs armed with spear guns are hunting him, and in order to hide, he enters the wreck...

Jake watched the fourth tank zip past, sounding like a torpedo, a jet-stream of small bubbles in its wake. It meant things weren’t good topside. The SEALs had arrived with a sled – he should have seen that coming – and must have left someone in charge on the surface. Ascending now would only serve to deliver the Rose to whoever was up there. He had to descend. Nadia’s air had been so low her only option was to reach the hang-tank under Pete’s boat at ten metres, so he’d sent her up.

The hut at fifty-two, where he’d left the smaller, 'pony' cylinder of air – that was his destination. But he chased after the larger tank, looking for the bubble-stream – his own tank would be empty imminently, and the pony wouldn’t last long at depth. By descending again he was going way off the deco-tables, but decompression sickness was preferable to what the SEALs would do to him. Besides, it bought Nadia time, and she was resourceful.

Legs locked together, he dolphin-kicked hard, holding his breath, the speed of his descent pressing his facemask back against his forehead and cheekbones. For a moment he lost the stream of bubbles from the tank and slowed, circling to find them, then continued downwards. Whoever had dropped the tanks had tried to make it land on the Tsuba, and as he passed the wreck’s funnel he saw a familiar grey aluminium cylinder lodged against one of the shed-like structures on the ship’s aft section. As soon as he reached it he shut off the valve. There was no way of knowing how much air was in it, but a diver never wastes air, and the valve had only been cracked open a quarter of a turn, so he reckoned it was at least half full. Anchoring himself by placing the ends of his fins on the sloping deck, he picked it up, still barely breathing – determined to leave no trail for the SEALs – and swam to the hut where he’d left the pony. He entered the wreck.

He’d been inside this part of the Tsuba twice before, but years ago, so he didn’t remember it too well. Rather than switching on his torch, he reached into his stab jacket pocket and took out a thin plastic tube the size of a cigar, and bent it till the mid-section snapped open. The light-stick began to glow a dull fluorescent green, casting a ghoulish light on his surroundings: a corridor straight ahead and up, then a staircase leading deeper into the ship. He took a short breath and headed in.

At the foot of the rusted metal stairs was a square room, algae-encrusted pipes lining floor and ceiling. The room had a single opening at the lower end – too small to get through with all his gear on – and at the other end a sealed hatch. First things first – air – since his main tank would be empty soon. But it was hard to think. The inevitable narcosis made his brain feel like a sponge soaked in rum. Concentrate! Three tanks: one ten-litre half-full, one nearly empty, and the smaller three-litre pony cylinder. Two SEALs. What to do?

His brain wasn’t co-operating. It was like staring at words, unable to decipher their meaning. On the surface he could work it out in an instant. A light flickered above, and he knew he’d run out of time. Clearly the SEALs had a detector and the locator code for the Rose, even though it only worked over a limited distance. He swam to the hatch, tried to heave it open. Rusted solid. Light beams danced around the bottom of the stairs. He swam back to the smaller hole at the lower end of the chamber, and dropped the pony bottle, with its regulator attached, straight through. He heard a clunk two seconds later.

As he turned around the first SEAL appeared. Nice rebreather kit, he had to admit; serious, professional. Jake pulled out his diver’s knife – Sean’s knife – and faced him. But the SEAL aimed a spear-gun at him, and gestured for him to drop the knife, just as the second SEAL arrived, squeezing in next to his comrade. Jake knew he might be dead either way, so he turned his back and went to the opening, and shoved the Rose, inside its bag, through the hole. He heard it hit bottom.

He expected to be speared at any moment, but the two SEALs stayed put, one of them nodding to the knife still clasped in Jake’s hand. Their eyes looked clear, alert, whereas he knew his own would appear groggy, half-closed and bloodshot. He let the knife slide from his grasp. One of the SEALs handed his spear-gun to the other, then approached Jake, his own knife drawn, and pushed past him to the opening. He shone a torch into it, then grabbed Jake’s stab jacket, and began unbuckling it. He then backed away, pointed to the hole, then to Jake.

It took Jake a few seconds to understand. Two spear-guns. Two options. Retrieve the Rose, or be killed here and now, after which one of them would go and fetch it. Reluctantly he slipped out of his stab jacket and let the whole ensemble, stab and tank, drop to the floor, but he kept the regulator in his mouth. He felt naked. He checked his air gauge – thirty bar. At this depth, it would last a few minutes, tops.

Unbuckling the tank from the stab’s harness, he turned, relishing each breath, and faced the dark hole. It looked like a giant letter box. The only way in was to put the tank through first, then follow it. Without his stab jacket he’d sink easily, especially carrying the tank, and finning back up to the hole would be difficult. He pointed to the other tank lying on the floor, the half-full one. The SEALs both shook their heads.

So, that's how it was.

Clambering through the hole, tank first, Jake fell rather than swam down, the regulator mouthpiece tugging against his teeth. After five metres, during which he felt as if he’d just downed two pints, he hit the metal floor. The SEALs must be shining their torches downwards, as he could see everything lit up in stark twilight, small clouds of silt puffed up from the floor where he’d landed. A completely sealed room, no other way out, but there was a tall metal cupboard, mesh doors hanging off their hinges. He found the bag and could see the Rose inside, blinking innocently next to his pony bottle. He stood over the pony as he fished out the Rose, so they couldn’t see what he was doing, and moved the pony and regulator into the cupboard, along with the bag, then turned to face the two torch beams.

He kicked hard, causing a cloud of silt to mushroom up from the floor, kicked a few more times, then launched upwards, finning furiously to climb back up to the letter box, cradling the almost-empty tank in his left arm. He passed the Rose through to one of the SEALs, then held onto the lip of the hole, and heaved his tank through, sure it would give out at any moment.

Jake expected the worst. He wasn’t disappointed. They yanked the tank from him, tore the regulator from his mouth, and then he saw the tip of a spear-gun right in front of his facemask. He pushed sideways with his left arm against the opening, just as the SEAL fired. White-hot pain lanced through Jake’s shoulder. He spiralled down into the cloud of silt, banging his other shoulder against the bulkhead. Another spear phished past him, slashing his wetsuit, cutting his thigh, but that was minor, a flesh wound. The torch beams were scattered by the silt, two suns trying to break through cloud. Good, they couldn’t see. Come and get me.

He landed in darkness, knew they would be reloading. He clawed his way to the cupboard, groped desperately for the pony’s regulator, and found it. He gasped in air, but breathed out carefully, into the top of the cupboard, so the bubbles were trapped there. The torch lights continued to hunt him, but Jake knew the silt would take ten minutes to settle. Two more spears shot down, one clanging into the floor, the other striking the top of the cupboard. The beams waved some more, then it darkened. He heard a loud hiss from up above. They were emptying both his tanks.

Bastards.

Jake squeezed his eyes shut, dared to touch the short metal shaft sticking out of his shoulder, and immediately wished he hadn’t. It wasn’t in too deep – the spear’s momentum had been slowed by his neoprene wetsuit – but he had no intention of ripping his shoulder wide open trying to extract it.

It grew dark again, and he heard clangs as the SEALs departed, leaving him to die. He slumped down inside the cupboard, and breathed heavily from the pony. It wouldn’t last long, but it didn’t matter. This was it. He’d been beaten. He’d finally join Sean. Not the way he’d intended.

The pain burned. He was losing blood. Where was nitrogen narcosis, or for that matter, oxygen poisoning, when he really needed it. He sucked in a few more breaths, knowing these were his last. He wondered what Sean would say. But he already knew what his son would say. Get the fuck up! That’s what he’d say. Nadia and the others are on the surface depending on you. You weren’t there when I most needed you, you’d better be there for them!

His eyes blurry, Jake staggered out of the cupboard. He released his weight-belt and lowered it to the floor. He found the bag he’d used to carry the Rose, and breathed out into it, then swam a few strokes upwards, carrying the pony, his teeth clamping down on the pain from his shoulder. When he got through the entrance, he found Sean’s knife and sheathed it. Each time he breathed out, he did so into the bag, creating a small balloon.

Drunk with pain, he made his way outside the ship, and stood for a moment on the deck. What are you waiting for? Sean said.

Jake kicked off, hanging from the homemade balloon that billowed as he ascended, and as the water pressure reduced, the bag began to lift him. He could almost feel the nitrogen flashing out of his bloodstream, forming small bubbles, searching for his joints, his heart, his brain. Just another way to die underwater. At thirty metres the pony resisted his in-breath. Sudden, though not unexpected. He was out of air. Forget about it. Every diving instructor knew the physics. From here on the air in his lungs would expand, and he wouldn’t need to breathe in, just breathe out, as if whistling, and by ten metres, he’d need to exhale in one long continuous scream. That would come easy. He let go of the pony bottle, withdrew Sean’s knife, tilted his head back, and began the long exhale.

Praise for 66 Metres:

"A great read that kept me turning the pages right from the start. Fellow divers will love the detail the author has put into this, as well as the story itself. Thoroughly recommended!"

'Deep diving meets suspenseful underwater action!"

"It’s clear the author knows his stuff about diving."

"Massive page-turner, read it in one long flight!"

"Couldn't put my kindle down!"