I sent this article to everyone I know who might go in the water. I received some additional comments from a grand nephew who spent time as a professional lifeguard. It adds some additional tips and ideas. I have included it with his permission.
"I was a lifeguard at a water park and I estimate I pulled 40-45 people out of the water during my 3 summer stint. The points made in this article are valid and I would make just a couple additions:
A scared expression. Generally the eyes are only glassy when someone has been drowning for a while. The easiest way to tell if someone is in trouble are the eyes. It starts out with a very scared look, no matter how well they appear to be swimming. I've seen adults or children who appear to be swimming well, but have a terrified look. They know they are in trouble, or at least feel like they are, and are soon going to be. I've also seen children who swim so terribly that they look like they are "movie drowning", but they have the biggest smiles on their faces. These kids are fine, but they need to be watched, or else they could run into trouble and that brings us to the next point:
They stop in their forward momentum. A swimmer who is happily swimming no matter how terribly, as long as they are moving forward they are fine for the time being. But if they ever stop moving forward, when they are trying to swim, they are probably too tired to continue. No matter how long you wait for them to resume, they simply lack the strength, and will shortly start to exhibit the signs listed in the article. If we ever saw a kid stop in his momentum, we didn't wait to see the scared expression that shortly follows, we just jumped in and pulled them out. I had more than one kid/parent tell me they were fine, and didn't need help after I had pulled them out in this scenario. I just smiled and left them to fill out the paperwork with the supervisor
The circumstances are different in an unsupervised lake, or pool. It's up to the parents to keep an eye on the kids, and each other, and if they get involved with what they are doing, or stop paying attention, then they could easily miss the easy signs. I used to drive Nicole nuts when we went to a pool, because I spent more time watching people than swimming, but I've lent my arm to more than one kid who got too tired in too deep of water, when I was swimming with the family. You only have about 4 minutes from the time that someone stops breathing before brain damage begins, so the window to help is really small. If the person in distress slips under the water (not everyone floats, I've pulled people from the bottom too) you may not see them until it's too late. " Bryan Brady