Open water swimming has a habit of hitting you with the unexpected. Experienced English Channel swimmers will therefore tell you to “hope for the best but prepare for the worst”. You will hear stories about the weather changing suddenly mid crossing or swims that were expected to take 12 hours lasting for 18.

But it’s not just on major marathon swims that the unexpected can happen. I recently took part in the British Long Distance Swimming Association’s swim in King’s Lynn, which is their last event of the season and one you can do without kayak support. It’s an easy swim to navigate as it’s in a straight channel. The sun was shining and the day was calm so, although the water was a slightly fresh 15.3 degrees (and this was a non-wetsuit event), I was looking forward to a straightforward 4.5km swim.

Part way into the first lap I began to suspect something was amiss. The turn buoy just never seemed to arrive. With the sun shining in my eyes I began to worry I’d missed it but other swimmers and the support kayakers were around me, so clearly not.

Eventually we turned and finally completed the first lap of three. It was supposed to be 1.5km. I don’t wear a watch when I swim but I knew that I’d been swimming for a lot longer than what I’d normally take for that distance. The swim was obviously going to be considerably further than anticipated. This presented two problems.

Firstly, 4.5km is about the limit I like to swim without having something to eat. I knew I would struggle and didn’t have any gels hidden down my trunks despite having written about that previously and having packed one in my bag for that purpose. In the excitement of getting ready for the swim (and fooled by the glorious conditions) I simply forgot. (Note to self: prepare a check list before next swim.)

Secondly, I’m not the biggest fan of cold water. I know a lot of people don’t consider 15 degrees to be cold but I’ve taken part in the studies and know how quickly my core temperature drops when swimming in these conditions. This could potentially be quite unpleasant.

Completing the first lap with these two negative thoughts on my mind was the closest I came to quitting. The spectators and officials looked warm and contented on the sunny grass bank. Wouldn’t it be so much nicer to join them, have a hot cup of tea and piece of cake and watch everyone else rather than staying cold and hungry for at least another hour?

On the other hand, I don’t like to give up, so I had to find some positives. I focused initially on just swimming. I noted that I had found a good rhythm (something that doesn’t always happen) and was comfortable with the pace. I ran through a mental checklist from hand entry, to catch, breathing, hips and kick focussing on each in turn and making minor adjustments. The actual swimming was feeling good.

I then thought about the cold. This is something many swimmers tell you not to do (urging us to think warm thoughts instead), but I find it useful. Having previously suffered from hypothermia, I’m alert to the danger signals and want to make sure I don’t miss them. My feet and fingers were numb, and the water felt cold on my skin, but inside I was still warm, I wasn’t shivering and my arms were still moving fine. This was good; I was coping with the temperature.

Coming through on the second lap there was no question of quitting, even though it felt as if that was already the full distance. It was two thirds done and I was in a positive frame of mind.

The cold and lack of food really began to bite on the third lap and my swim stroke began to falter, so now I had to come up with something new. I started to think about how good I’d feel about completing the swim; that the extra distance in cold water was an unexpected training bonus; that this would be a confidence booster for tackling other tough swims. I also started to think what I might write about. Eventually I fell back on that old swimmer’s mantra: just keep swimming. Keep putting one arm in front of the other and you’ll get there. And I did.

After finishing the swim we learnt that a GPS error meant the distance was 7km, not the planned 4.5km. That’s more than 50% extra. But I didn’t hear anyone complaining. On the contrary, the majority of swimmers were pleased they had accomplished something more than they had anticipated and paid for. The organiser was even joking about charging extra.

Sometimes when the unexpected happens you’re prepared and can deal with it. Other times the only resource you can draw on is what goes on inside your head. Instead of cursing, embrace what’s happened and make the most of it. At the very least, it will give you a story to tell.