Miracle on the River Trent

This is one lucky lady
http://www.bbc.co.uk/news/uk-england-not...mshire-23189453

I don't know you cant even have a quiet swim without somebody sticking their nose in.

I think she found some sort of equilibrium in floating on her back that any attempt the right herself would have ruined and put her into difficulties.
When I was learning to swim, at age 40, I found it fairly easy to float about on my back but was too scared to do so because at some point I would have to right my self to get out of the pool.
That's where thing can go horribly wrong for a non swimmer.