I’ve been swimming in San Francisco Bay for three years now, waters that are not known for being “tropical” in temperature, so my idea idea of “cold” is somewhat different to what it was when I was living back in Australia.
That said I do feel that many of the swims I would like to do are currently not possible because of my cold water tolerance – I would not be confident of doing 4 hours at 60F for example, which is a temperature that is considered ideal by many marathon swimmers.
The bulk of my swimming in the Bay has been a single circuit of Aquatic Park which takes me 30 minutes – depending on the tide and how much I muck about with goggles and sightseeing. In my first winter of swimming in the Bay I was able to manage to make it through the entire winter doing these single coves, swimming in temperatures around 50F/10C without too much difficulty – I did have one scare swimming on my birthday when I thought I might not be able to make it back to the club so go out short, but I think that was mostly psychological.
The short jaunts in the water that I have been doing I think have served to acclimate me to the idea of cold water, but not the reality of extended swims. The only way to really get used to swimming for a long time in cold water is (not surprisingly) swim for a long time in cold water.
So to break through the cold barrier and become a “proper” marathon swimmer I’m focusing this summer on bumping up my cold water mileage, firstly by not allowing myself to do anything less than two coves (~1 hour) when I do get in the Bay (which also has the benefit of getting a better workout in) and secondly by making a determined effort to increase that number.
So far I am a month into this program and have 8 double coves and 3 triple coves under my belt. I actually felt so good on my first triple cove that I was up for a fourth but discovered that I start to chafe in the Bay after 90 minutes.
If I ever manage to exceed four coves I will need to start putting out feeds, but for anything up to 2 hours of swimming I’m confident I can handle without hydration or calorie intake.
I fully expect that come winter I will have to cut back on this resolution, but I would like to hold to hour long swims for as long as I can (e.g. at least below 55F) and see how far I can take the longer swims. We’ve had some deliciously warm (for San Francisco) waters lately, and I am hoping that it means we will have low 60’s all the way through September.