My sister-in-law swam the channel a few weeks ago, under the supervision of a pilot from the linked association. A direct point to point swim is around 33km. Due to the tides and the timing of her swim it was a 58km crossing. Incredible!

Channel crossing is usually critically aided by timing tides that help suck you out when leaving England, and suck you in as you approach France.

https://www.channelswimmingassociation.com/swim-advice/chann...

I tried to swim the Channel but failed after 9 1/2 hours and 19 miles in 53 F degrees water. I did, however, win the award for the best disabled swim of the year 1980.

https://www.channelswimmingassociation.com/awards?award=39&y...

It's tricky when you only have one hand and you can't kick with your legs. So it goes.

Most open water distance swimming takes the tides into account.

Here's an article that gets into it a bit with some data to boot...

https://evanmorrison.com/swim/posts/manhattan-swim-tides/

I learned about long distance swimming by reading Lynne Cox' autobiography "Swimming to Antarctica" (2004), which I can recommend if you are interested learning about the sport. She broke the womens and mens speed record for swimming the channel at age 15 and 16 and continued to pile on remarkable records all over the world.

https://openlibrary.org/books/OL7365713M/Swimming_to_Antarct...