‘So what do you think? A First World War minesweeper?’ Costas asked.
Jack touched the audio control on the side of his helmet to compensate for the high pitch in Costas’ voice, caused by the increased helium now streaming into their breathing mixture as they descended beyond safe air- diving depth. ‘That’s Scott Macalister’s best guess. The state of metal decay in this environment suggests we’re looking at a wreck maybe ninety, a hundred years old. That puts it bang on time for the 1915 Gallipoli campaign, the biggest single cause of shipwrecks in the Dardanelles in recent times.’
‘Macalister’s got a database, hasn’t he? I told you I saw his Admiralty wreck chart.’
‘He’s plotted all known wrecks from the campaign. But he says the records are sketchy for smaller vessels, especially from the Turkish side. There were gunboats, torpedo boats, balloon ships used for gunnery spotting, lighters, mini submarines, some of them used in covert missions to land men for sabotage. For all these vessels the approaches to the Dardanelles were suicide alley, running the gauntlet big-time. The Turks had no aircraft and the British only used theirs for reconnaissance, but there were big guns on either side, British battleships off the island of Tenedos, Turkish shore batteries on the mainland. The Turks had batteries at Besik Bay, the harbour of ancient Troy. They would have had the range of this spot where we are now.’
‘And there must have been mines.’
‘Mostly within the Dardanelles, where the Turkish minelayers could operate more safely, but some daring captain may have tried to lay mines this far out. The minelayer captains were heroes to the Turks, like U-boat commanders or fighter aces. Always pushing the boundary. That’s why Macalister thinks we may have a minelayer, or more probably a minesweeper. The British used converted trawlers as minesweepers, about this size. The civilian crews made the transition from trawling to sweeping easily enough, but the fishing boats had draughts that were deeper than was ideal for minesweeping, and there were plenty of accidents when they hit mines anchored just below the surface.’
‘Seventy metres. We’re nearly there.’ The water around them was now a dark indigo, becoming almost black below. Jack rolled over and looked up. He could just make out the hull of Seaquest II, but no longer the sparkle of sunlight on the surface. He rolled back, and suddenly could see the mottled sand of the sea bed some fifteen metres below. He switched on his headlamp, startling a school of bream that darted off out of sight ahead of him. ‘That’s a good sign,’ he said. ‘A school like that over a featureless sea bed usually means a reef or a wreck nearby.’
‘Bingo,’ Costas said. They were now less than ten metres above the sea bed, and Jack could see the ripples in the sand. He angled his beam up slightly, and there it was, a mass of decaying metal rising five or six metres above the sea bed, sitting in a deep scour channel that extended out of sight ahead of them. As their headlamps converged on the wreck, the dark blue transformed into vivid reds and yellows, a mass of encrusted anemones and other sea life that clung to the corroding metal; some of the rust lay exposed where the structure had recently collapsed. Jack was always amazed at the speed of decay of metal-hulled ships underwater; most of them would vanish long before the wooden hulls of antiquity that were preserved in anoxic sediments below the sea bed.
He paused to orientate. It was one thing seeing an entire wreck in one image on the sonar screen in the operations room, another trying to make sense of it underwater, from a different angle and in confusing light conditions. The view ahead was a tangle of structure and marine life, but he could see that they had come down behind the stern of the vessel; they were looking forward to where the deckhouse had collapsed, leaving only a few girders intact. The ship had evidently sunk upright but then heeled over to port, with the deepest scour channel running along the starboard side just ahead of Jack, where it angled into the current. As he panned his beam over the stern, he could see that the damage was more than just natural decay. ‘That’s a hell of a hole,’ he murmured. Costas followed the direction of his beam and swam forward, peering under the jagged metal of the deck, pointing up at the parallel struts running athwartships that they had seen on the sonar image. ‘Looks like her entire stern was blown off,’ he said. ‘That’s consistent with a minesweeper, snagging a mine and accidentally detonating it. On a vessel of this size, the shockwave from two or three hundred pounds of high explosive would probably have killed everyone on board instantly.’
Jack panned his beam to the right, along the exposed starboard side of the hull. The deepest part of the scour channel was in shadow, under the corroded remains of the keel. ‘I think I’ve found what we’re looking for. I’m dropping down into that scour channel to collect sediment.’ He glanced at the LED readout inside his helmet. ‘We’ve got twelve minutes, otherwise we spend the afternoon in the recompression chamber. Not my favourite place.’
‘Roger that. I’m going to take a quick recce inside the hull.’
‘Be careful. God knows how stable this is. Some of those girders are probably completely corroded, only held together by marine accretion. And remember, this has to count as a war grave. Go easy.’
‘Roger that. Eleven minutes.’
Jack swam up and over the surviving framework of the stern deck towards the scour channel, trying to decipher the jumble of structural elements that had fallen from the deckhouse and starboard railing. The vivid reds and yellows of marine life added further confusion, and he switched off his headlamp, reducing everything to a uniform dark blue. He was conscious of Costas swimming under the deck frames below him, towards the hull amidships where the remains of the engine room should lie. The beam from Costas’ headlamp flashed through jagged holes and fissures where the metalwork had corroded away. Jack sank down until he was inches above a thick metal girder that ran longitudinally along the deck for at least ten metres, from somewhere in the gloom below the deckhouse to a point behind him where it had been buckled upwards by the force of the explosion that had destroyed the stern. The girder was well-preserved, clearly a high-grade steel. He stopped, and stared. It seemed oddly out of place. It was a flat-bottomed rail from a train track, evidently used to support something on the deck. He reached out to it. Even a slight touch released a cloud of red oxide, and he withdrew his hand. He had seen this before.
He remembered where. Two days earlier, Macalister had taken him on a tour of the 1915 Gallipoli battlefields, and they had finished in Canakkale at the Turkish naval museum. The highlight was a replica of the celebrated Turkish minelayer Nusret, which had laid the mines that sank three Allied battleships in the Dardanelles. That was where he had seen it. T wo reused train rails, laid parallel on the stern deck. He finned two metres to the left, peering through the red oxide haze he had stirred up in the water, and then carefully felt the mass of rusted metal. Bingo. It was another rail, exactly the right distance apart. He pushed back, and then finned above the plume of rust where he had touched the metal. He looked along the line of the two rails, towards the collapsed mass of the deckhouse, and saw a dark form, oval-shaped, directly above the place where Costas’ headlamp beam was flickering. He stared at it, swimming closer. Then he froze. That shape, the shape on the sonar readout he had thought might be an ancient pithos, was not a boiler. It was something else.
‘Costas.’
‘Jack.’
‘You need to get out of there.’
‘Just a few moments longer.’
‘Costas, listen to me. This isn’t a minesweeper. I’ve just found the rails on the deck. It’s a minelayer. And there’s a mine still in the rack. That shape from the sonar I got all excited about. Directly above you.’
‘Relax.’
‘What do you mean, relax?’
‘I mean, I know. German Mark VI contact mine. Never seen one of those before. Underwater and live, that is. Macalister told me most of the mines laid by the Turks were supplied by the Germans, so that makes sense. Big question is, which type of detonator? I wish I could see it more clearly. So much stuff in the way.’
There was a dull clang, then another. Jack’s heart sank. ‘Costas, I hope to God you’re not doing what I think you’re doing.’
‘We’re in luck.’ Costas’ voice sounded slightly strangulated. ‘I’m upside down, but I’ve got my face right against one of the horns. You know, the protruberances that stick out of a contact mine?’
‘I know what they are,’ Jack said weakly. ‘That’s why they call it a contact mine. You hit the horn, and the mine blows up. Exactly how close are you?’
‘Oh, about four, six inches.’ There was another clang, and Jack’s heart seemed to stop. Costas made a straining noise, then spoke again. ‘Phew. You can really relax now.’
‘Relax?’
‘Yeah. Relax. Kind of. I’ve worked out which type. The early horn contained a glass phial filled with hydrogen peroxide, surrounded by potassium percholate and sugar. When the phial was broken, the acid ignited the sugar and the mine exploded. The advanced type leaked the acid into a lead-acid battery, energizing the battery and
