The three metre board has a strain sensor in the hinge because a cracked board is a broken neck. Every night it logs a walk to the end, a bounce, and a launch, at the loads of an adult. The pool's underwater alarm, which listens for the sound of a body entering the water, hears one. The surface, on the camera, does not move.
I am the pool operations lead at a leisure centre with a diving pit, and the three metre board is the thing in the building that I am most careful with.
What it logs.
There is a strain sensor at the fulcrum because the boards are aluminium and aluminium cracks without telling you. It records the load. A child on the end is a small number, an adult a bigger one, and a hurdle, which is the step and bounce a diver does before the launch, is a spike.
Every night, at about half past eleven, the board logs a person.
Seventy kilos, give or take, walking out. Three steps, by the timing. A hurdle. A launch, which is the sensor going to nothing as the board throws its load off. Then the board, empty, ringing down the way it does after a good dive, which takes about two seconds.
The alarm.
The diving pit has a hydrophone, a microphone in the water, which is part of the drowning alarm. It listens for the sound of a body entering and for the silence afterwards. At the moment the board launches, the hydrophone hears an entry. A clean one, by the shape of it, a diver going in vertical with not much splash.
The surface camera shows the water flat. The board, on the same camera, bends and throws and rings. The water does not move.
What has been checked.
The strain sensor, replaced. The hydrophone, replaced. The board, taken off and a new one fitted, and the new one bends at half past eleven.
The board on the camera. It bends under a weight that moves along it, step by step, and the bend is exactly where a foot would be at each step, and there is no foot.
I put talc on the board one night. Fine, over the whole length. In the morning there were footprints in it, to the end, and at the end the two prints were close together and the toes were over the edge, the way a diver stands, and then nothing, and the talc at the end was disturbed the way it is by the board flinging, and the water below had a skin of talc on it in the shape of a ring, the size an entry makes, and nothing had entered.
The dive.
I have watched the strain trace and the hydrophone together enough nights to know the dive. It is a forward dive, straight, from a hurdle. It is the first dive you learn from the three metre and the one you do at the end of a session when you are tired and want to go in clean.
The entry is good. Whoever it is was good.
Who.
I have asked. The building is old on the pool side and the diving pit is older than the leisure centre. Nobody has died off the boards here. I have checked the records and the newspapers and the coroner's lists, and nobody has died off our boards.
Which means it is not somebody who died here. It is somebody who came here to dive, from wherever they are, because the board is a good board and the pit is a deep pit, and I have started to think that is worse.
What is done about it.
The strain log is the safety record for the board, and the board's fatigue count is one cycle a night higher than the day's diving, and it will be replaced a year early on that count, and I have signed the order.
What I do.
I run the pool side.
I stopped one night at the top of the three metre steps, at half past eleven, with the hall dark, before it came.
I heard the steps on the board before I saw it bend. Bare feet on wet aluminium, which is a sound anybody who has done this job knows. Three steps. The hurdle, which on a board is a sound like a drum. The board threw. The water below me took a diver I could not see, with the small clean sound, and was flat.
And then, from the water, from the deep end of the pit, the sound of somebody surfacing and breathing out, as everybody does after a good one. And then the ladder. Wet feet on the ladder rungs, one at a time, coming up out of the water, and the steps coming across the tiles, to the foot of the tower I was standing on, and starting up.
I went down the other side. I have not been up at night since, and I have moved the ladder, and it uses the ladder where it is.