I don't even like how cold the water feels in the pool when I first get in. Can't imagine what 14/57 degrees would be like. As a result, I've only done open water swimming in the summer time. I've seen other open-water swimmers actually recommend putting on a few pounds, but that's probably not a good suggestion for this website.

Coldest swim for me was 67 degrees F and I was in a full wetsuit. This was my first cold-water swim and a fellow swimmer recommended to start, jump in and get your face the initial cold burst, then start your swim with your head mostly out of the water, with it turning how you would typically breathe. So I had my chin and my mouth under, with my mouth coming out for breaths like I normally would. I then gradually lowered more of my head into the water. Personally, I heat up really quick when I swim, so my head was in normal position within less than 400 meters. I have used this technique many times since and it hasn't failed me yet. There are probably better ways, since this strains your neck and doesn't promote good swimming form, but it works for me.