In the end, the boat turns and the lady and the two kids disappear...
 

Hi,

I think this is a British black and white movie from the sixties, but i'm not sure.There's a lake, were the lady goes with the two children, and suddenly, without explanation, the boat turns and they all die...!

Are you saying the boat capsizes (flips upside-down)?

Was it a rowboat, or something bigger with passengers -- like a ferry boat?

Can you remember anything else about the story? There's not much information here to work with I'm afraid.

Re: In the end, the boat turns and the lady and the two kids disappear
 

The Woman in Black 1989 maybe. A tree limb falls and drowns them. The revenge from the witch on the lawyer.



https://www.imdb.com/title/tt0098672/

Thanks! It was a small rowboat with only a lady and two kids, and flipped upside-down.It´s kinda like "The Haunting) from 1963, i think...

Thanks! It's a much older film (fifties or sixties)...

There's a classic British horror from 1961 called 'The Innocents'. In the following clip from that movie, there are children, a lake, and a row boat.

Note:
'The Innocents' is on my wish list of 'movies-to-see-before-I-die', so I'd like to request that nobody divulge any plot details or spoilers here -- if it can be avoided. Cheers.

https://youtu.be/VEkAKpFMJW4