Of course, after a week of record-breaking heatwave Saturday was chilly and rainy, and the waves were making off-putting crashy noises on the pebbles. I registered in the marquee at the finish line and set off for the start point at 'the stone groyne opposite Lodmoor Country Park', looking, in my towelling robe and competitor's paper wristband, as if I'd escaped from a hospital.
Swimmers doing the full 2.4 miles from Bowleaze Cove were already passing the groyne, their halfway mark, accompanied by canoes and jetskis ready to rescue anyone struggling. I changed into my wetsuit in the rain and stood around waiting for 45 minutes, easily the worst part of the experience.
At last we were given a briefing and called forward to enter the water. We crossed the timing mat in twos and threes and set off for the first buoy looking, in the words of my line manager when I sent him a picture, 'like a bob of seals'. There were huge waves to tackle as we headed out from the beach, then a right turn at the buoy and we struck out for the marquee, just visible across the bay.
We soon separated out. I navigated by the buoys when I could see them, and by following my fellow-swimmers when I couldn't. The waves made it hard to tell if I was making headway, or even going in the right direction, and the salt water getting in my mouth was disconcerting. The velcro band holding my timing chip came off my ankle, and I had to make a grab for it before it sank, wrapping it round my wrist instead. I'd never gone such a long distance in the sea before, but my wetsuit was buoyant and I knew I wouldn't have to go far towards the shore to be back in my depth. And if I couldn't make it, an arm stuck in the air would bring a marshal to help me.
But I did make it, staggering up the beach and through the finish arch in a time of 58 minutes and 38 seconds. I was given a medal and a can of Red Bull, then I got changed and went off with Howard, who had been spectating faithfully and also carried my possessions to the finish line, to have brunch followed by a Dorset Apple Cake flavoured ice cream.
The starting line, looking forbidding.
The bob of seals sets off.
Emerging from the sea just like Honey Ryder in Dr No.