I know that we've pretty much debunked the myth from a thousand childhood TV shows that people commonly die in quicksand but right behind that trope were whirlpools.
"What’s the most amazing thing you’ve experienced?
In the sense of incredible, in Nazare, I got swept into a whirlpool in the open sea, after coming out of a wave in front of Fred's eyes. I sank with my board very quickly and very deep and then the ocean released me and fortunately there was no waves following and Fred was there to pick me up. It was hard to believe what happened."
- Big wave surfer, Justine Dupont
https://www.manera.com/en/athlete/justine-dupont.html
"In 2023, Justine dropped into what may be the biggest wave ever ridden by a female and does it 105 miles at sea at the Cortes Bank during the filming of an upcoming season of the HBO docuseries “100 Foot Wave.”"
https://bayareakitesurf.com/justine-dupont-is-the-2023-waterperson-of-the-year/
That makes me shudder. I have short falling/whirlpool nightmares sometimes.
There were big standing eddies at Deception Pass that I saw from up high on the bridge several times. No desire to go over them. Then again I did whitewater rafting and got thrown off once in a class 2 or 3 and it was a bit exciting.
Hydraulics from rapids, etc are really scary. When I was in Scouts and we did some really long canoe trips, short dams (4-5ft high) across the river were always scary because the flat water in front of them obscured the drop. We'd have to paddle close up to portage around and there was always the fear of going a bit too far without realizing it.
Those short dams are actually really dangerous