We used to go to the river in the summer as you do but I couldn't swim very well but I was a decent dive and glider, there was a mini whirlpool we used to dare ourselves to dive through and we did it many times.
One time I misjudged and went to stand up but my feet didn't touch the bottom, I panicked and in all intent and purpose was drowning, a stranger dived in and pulled me out and got me back on the bank.
It must have been 79/80 so 7 or 8, never told my parents when I got back in and nobody else said a thing, I'm sure I would have said thanks to the man on the bank at the time but he probably deserved more praise tbh.
I always remember he gave me a bottle of Underwoods cream soda to drink the old 10p back glass bottle jobs, the nicest drink on earth but you can't get it now or for years tbh
When I was 4 we went to Blackpool on holiday, I'm not saying parenting in the 70's was lax but I somehow ended up on the cliff wall looking over the edge as if it was just a 2ft drop and not a very long way to rocks and stuff below, unceremoniously yanked back to the proper path when it was noticed, wasn't close to death but it might explain the first story and the lack of fear we felt as kids back then.