Actually, I am a skipper and because of that I had to go through quite thorough training of which large part is focused on saving people in Man Over Board situation.

I estimate full 1/3rd of entire training was devoted exclusively to getting a person back on the ship if they happened to fall into water while underway.

It is said "people do not splash" because if you are focused on looking for flailing hands and splashing water and shouts for help then your are missing most people that drown.

But it doesn't mean people don't shout and don't flail. They do. Just not most of the time.

Depends on which stage of drowning they are in. If they've just fallen in, they might still be flailing away. If they've been flailing for a minute already, then, yeah, thy might be tired. Plus, it's hard to shout when your lungs are full of water. I can't do it with a mouthful of water let alone lungs. My ventriloquist dummy on the other hand won't shut up while I'm drinking water.

"Directly behind them, not 10 feet away, their 9-year-old daughter was drowning…

How did this captain know—from 50 feet away—what the father couldn’t recognize from just 10? Drowning is not the violent, splashing call for help that most people expect. The captain was trained to recognize drowning by experts and years of experience. The father, on the other hand, had learned what drowning looks like by watching television."

2013 Slate article: https://slate.com/technology/2013/06/rescuing-drowning-child...

someone in the process of drowning, as in exhaustion and/or panic causing ineffective motions that do not get the head far enough above water to take an adequate breath won't be able to splash or yell.

Someone who is not exhausted and not technically drowning yet but who will be if left for another 10,15,60 or whatever minutes does have the ability to yell and splash.