A tale of two bridges, too much chocolate and pacing strategy

A few days before it took place, Jeremy Laming from Henley Swim asked me if I would be a pace swimmer for the 2015 14km Henley to Marlow Bridge to Bridge swim. The weather looked promising and I hadn’t done any long distance swims for a while so I said yes.
The Bridge to Bridge is billed as a ‘sportive’ rather than a race but I’m pretty certain that if I was a regular entrant I would have tried to complete the distance as quickly as possible. However, this was a different challenge: could I please swim at a steady pace of around 25 minutes per mile and aim to finish in 3 hours and 44 minutes. I was to lead the second fastest pace group while Dan Bullock of Swim for Tri led the fastest group.
We started together in the final wave and I had to fight my competitive instincts and not try to keep up and draft the front swimmers. In fact I had to purposefully hold back and allow a gap to open up:  very strange but also, once I got used to the idea, very pleasant to swim at a more relaxed pace than usual. I decided to treat it as a training swim and spent 14km trying to swim with my best possible technique while taking time to enjoy the scenery.
We arrived at the first lock and feed station after about an hour. I was already hungry so I grabbed two large handfuls of chocolate as I walked past the lock gates.
There was a slight hold-up here as Dan’s pace group had caught a large pack from an earlier wave and was waiting for that to move on. As we waited, a number of swimmers who’d been going at my pace decided to move forward and join Dan’s group. Once they had started I set off again a few minutes later with my now diminished pack.
The next section was confusing as we threaded our way through large groups of swimmers from earlier waves. It was hard to see what was happening with the swimmers in my group so I just tried to keep swimming at a steady pace and hoped that they would keep up. The second feed station and half way point came around sooner than expected, I ate another few handfuls of chocolate, we regrouped and set off again.
At this stage we started to overtake a number of pink-hatted swimmers who must have been with Dan’s group earlier and had now dropped off the pace. The next lock marked the 10km point. I filled up with yet more chocolate and was pleased to see that most of my pace group was still together and, most importantly, still smiling.
On again we went, with a brief pause to allow a chain ferry to pass. And then I discovered that chocolate is perhaps not an ideal energy food: I was starting to feel sick and didn’t have much energy!
Luckily it was only 1500m to the next lock where I grabbed a quick energy gel (I’ve written before about the wisdom of keeping one of these up your wetsuit sleeve or inside your costume). It didn’t do much for the sickness but it gave my flagging arms a welcome boost for the final 2.5k stretch to Marlow where we arrived about five minutes ahead of schedule, which I blame on a stronger than expected current.
So, what can we learn?
1)      Whatever distance you swim, pacing is important – not just for your time but for how you feel along the way. You will enjoy your swim much more if you hold something back at the start and are overtaking people towards the end rather than the other way around.
2)      Chocolate is very tempting and very satisfying when you are on a long swim, but you can definitely have too much of a good thing.