I have committed to swimming 10k down the River Dart, from Totnes to Dittisham in September '19. I've not swum more than one length of a swimming pool since i was 9 and had to jump in in my pyjamas to get a certificate. 

Luckily, I've been told that fat floats, so this should be very easy for me. It will be less easy for the skinny runts I'm doing it with - including my lovely wife and several good friends. 

Here's a link to a site where you can see videos of other silly people from years past. https://www.outdoorswimmingsociety.com/dart-10k-swim/

If you'd like to support our charity, Level Water, that'd be grand. They help supply swimming lessons to disabled children so that they too can get involved in such a simple, but often far too inaccessible, pleasure in life.