Chapter 5 The First Recording

She dropped the first element at four nineteen on the morning of the fourteenth. The tide was going out, and it was going out fast, and the water was that flat pale colour again, and the array site was two fathoms off the narrows, on the chart, and Ruan held the boat stationary over it for ninety seconds while she checked the sounder and the depth log and the position, and then he put the element over the side and let it sink and tied the mooring and turned the boat and motored home and did not look back. He came into the village at six and walked into the harbourmaster's office with the mud still on his boots, and sat down, and drank a cup of tea that someone had left on the counter, and said, to nobody in particular, that the water was right today and that it would not be right tomorrow and that she should not put the second element in until Friday. "Who are you telling?" asked the harbourmaster. "Everybody." The array came up at seven, on a cable, and Tamar had it in the car and across the village and into the cottage and onto the kitchen table and into the laptop by eight, and the laptop said that the element was alive and drawing twelve volts and sampling at twenty-four kilohertz and recording whatever the water was doing at a depth of twelve metres and two fathoms off the narrows and two miles from the shore, and the water was doing things. The water was doing a lot of things. There was the noise of the tide itself, a low, broad, dull roar, with a fundamental at about two and a half hertz and harmonics up to about fourteen. There was the noise of the boat traffic, a band of engine and propeller from about eighty hertz up, and it came and went in the pattern of the working day. There was the noise of the rain, on the surface, at thirty-thousand hertz and above. There was the noise of the seabed, which was the noise of the sand moving, and it had a shape to it that Tamar recognised from other sites, a slow, sliding, granular thing. And there was the noise of something else. She put on the headphones at half past nine. She had not put the headphones on until half past nine, because she wanted the room quiet first, and she wanted the laptop's fan at a steady pitch, and she wanted the heater off, because the heater made a click every ninety seconds, and she wanted the kettle off the stove, because the kettle made a tick every time the thermostat tripped. She put the headphones on and opened the spectrum and looked at the record. There, at the bottom of the band, at about seventy-eight hertz, with a second tone at about one hundred and fifty-six, there was a thing that did not belong. It was not a band. It was a line. It had an edge on either side. It was steady. It came in and out, in a rhythm that she did not recognise, and it did not move with the tide, and it did not move with the boats, and it did not fade with the rain. It was, at her first glance, exactly as loud as a buoy bell. She sat still. She put the headphones off and on and off and on. She opened the record a second time and looked at it again. At seven-eight hertz, the line held for one point four seconds, and then it was gone. And then, at one hundred and fifty-six, a second line, half as long, at the same time. And then, again, the first line, at the same place, at the same height, a minute and twelve seconds later. And again, at the same place, a minute and twelve seconds later. And again. She pulled the record back and looked at the beginning of the file. The file had started at four nineteen. The line was there at four nineteen. It was there at five. It was there at five thirty, when the tide was highest of the half, and it was there at six, when the tide had turned, and it was there at six-thirty, when the boats were coming home, and it was there at seven, when the village went to sleep. She pulled the file forward and looked at the end. The line was there at seven forty-one. The line was there at seven forty-four, and there it stopped, mid-tone, and the file ended, because she had stopped the record. She did not know that she had stopped the record. She sat in the chair with the headphones round her neck and the spectrum on the screen, and she looked at the line, and she looked at the number, and she looked at the number again, and she did not move for a long time. A bell buoy at Bellrigg, at forty fathoms, with a cracked bronze bell and a magnetic striker and a tide gauge attached, and the striker going off on a fixed interval. That was the reason. That was the only reason. She had read the specification for that buoy in a manual in two thousand and twelve. She pulled up the buoy record. The buoy at Bellrigg had been decommissioned in nineteen ninety-six. Its bell had been removed in nineteen ninety-eight. Its magnet had been removed in two thousand and four. Its casing had been written off in two thousand and nine. It had been scrapped, and the scrap had been collected, and the site had been re-registered as a marker buoy of no acoustic function. She closed the file. She opened the record. The line was there. She closed the record. She opened it again. The line was there, at seventy- eight hertz, at one point four seconds, at the same height, at the same place, one minute and twelve seconds apart. She took the headphones off and put them back on. She called the project office. "Ellerby," she said. "I need a technical call, tonight." "Say it." "There's a tone in the record at site one. Seventy-eight hertz. It's not equipment. It's not the buoy." "That's the buoy." "The buoy was scrapped in two thousand and nine." "Then it's the echo." "From where?" "From the dockyard. It's the dockyard." "Which dockyard? The dockyard is three miles inland and five kilometres up the river." "Then it's a reflection. There's always a reflection." "Ellerby." "What." "I need to put the second element in Friday. I need a diver. I need you to sign off a diver." "I'll sign off a diver. I can't sign off Friday. Friday's the weather. The weather's wrong." "Ruan said the water was right." "That's not a weather model." "That's not a weather model," she agreed. "It's a man who has been out on this water for forty years and who has never been wrong about it, and he's telling me that the water is right on Friday, and he's telling you, and he's telling everybody, and you're telling me to go out on Thursday because you were told Thursday was the day." There was a pause. "That's not how this works, Tamar." "That's how this works." "Put the second element in when the weather's right. Put the tone in the observations section as a dockyard reflection and move on. The consent schedule is fixed." "I'll put it in as a reflection." "Do that." She hung up. She put the headphones back on. The line was there. ---