The 6-hour swim is a marathon swimming staple. As many swimmers already know, it is the length of the qualification swim for the English Channel (and others), and long distance training camps routinely culminate in documented 6-hours swims, providing certificates for swimmers to dispatch to organising bodies as evidence. But as every experienced marathon swimmer knows, your qualification swim should just be one of many. To have completed the qualification swim is really just a starting rather than a finishing point in your training, and as your big swim approaches, the 6-hour swim, while always satisfying, should become relatively mundane. And while there is disagreement about how many long weekends are necessary leading up to a big swim, I would definitely say that you should be able to double up with relative comfort as the swim approaches, doing back-to-back 6-hour swims across two days. If you are completely wrecked at the end of 6 hours and can't recover well enough to swim again the next day, then you're probably not ready for 12, 15, 20 hours.
In the summer before my EC swim, I did 4-5 back-to-back weekends, plus I came to love the early season 6-hour swim at Swan Pool, which I did annually until I moved to North Yorkshire. I also did 6-hour swims with Swimtrek in Gozo, and on the Cork training camp. As a result, I learned to chop up a marathon swim into 6 hour chunks; in the EC, I changed my goggles at the end of the first 6 hours as the sun came up, and in my mind, I restarted the swim afresh. At the next 6 hours, I was rewarded with a black jelly baby to mark the start of the next 6-hour block. I did the same on both of my MIMS swims; the magic of the black jelly baby to reset the clock shouldn't be underestimated.
Times have changed in my training though, and when I stopped to think about it before writing this, I realised that I haven't done a 6-hour training swim since May 2013, in the run-up to my rather unsuccessful season of cancelled and aborted swims. I have swum over 6 hours since then - on both of my MIMS swims, and then the 8 Bridges swim last year, which involved 3 swims of 7+ hours; but it's been 3 years since I did any 6-hour training swims. This is partly because, since I got the Fastlane Pool, I tend to do longer, more regular pool swims more consistently than I was able to before. I am firmly convinced of the relative value of doing frequent 2-3 hours swims over my previous pattern (from necessity) of being relatively fallow during the week then hammering out long training swims at the weekend.
But with both Geneva and, more immediately, my 2-way / 1-way Windermere weekend approaching fast, it was time to get out there and get some distance in my shoulders... Plus, the weather forecast for the Bank Holiday weekend for the Lake District was for glorious sunshine. This doesn't happen very often, and the thought of all that water-warming sunshine inspired me to leap in the van and head to Grasmere to do my first 6-hour swim of the season - hopefully the first of many in my prep for Geneva. This was also the first 6-hour training swim I've done completely solo - just doing 2km laps of the lake with a tow-float carrying a drink bottle, plus a few gels down by the back of my costume, stopping in at the beach every 2 hours to restock. I was surprised how well it all went - I felt like I was swimming well, I didn't really get cold, and my energy levels stayed high. Over the winter, I've lost some of the habits of thought that long swimming demands, and I found my mind bouncing around problems with work for the first couple of hours. But by hour 4, I had settled down and started to find my marathon swimming-ness - an embodied disposition, a state of mind.
I've been more tired today than I had hoped, and obviously still have a lot of work to do, but it felt SO good to be back at it in such a tangible, substantive way. It feels like a very solid contribution to training; a marker of progress in a long journey.