Drowning does not look like drowning—Dr. Pia, in an article in the Coast Guard’s On Scene magazine, described the Instinctive Drowning Response like this:

1. “Except in rare circumstances, drowning people are physiologically unable to call out for help. The respiratory system was designed for breathing. Speech is the secondary or overlaid function. Breathing must be fulfilled before speech occurs.
2. Drowning people’s mouths alternately sink below and reappear above the surface of the water. The mouths of drowning people are not above the surface of the water long enough for them to exhale, inhale, and call out for help. When the drowning people’s mouths are above the surface, they exhale and inhale quickly as their mouths start to sink below the surface of the water.
3. Drowning people cannot wave for help. Nature instinctively forces them to extend their arms laterally and press down on the water’s surface. Pressing down on the surface of the water permits drowning people to leverage their bodies so they can lift their mouths out of the water to breathe.
4. Throughout the Instinctive Drowning Response, drowning people cannot voluntarily control their arm movements. Physiologically, drowning people who are struggling on the surface of the water cannot stop drowning and perform voluntary movements such as waving for help, moving toward a rescuer, or reaching out for a piece of rescue equipment.
5. From beginning to end of the Instinctive Drowning Response people’s bodies remain upright in the water, with no evidence of a supporting kick. Unless rescued by a trained lifeguard, these drowning people can only struggle on the surface of the water from 20 to 60 seconds before submersion occurs.”

From the original at http://www.uscg.mil/hq/cg5/cg534/On%20Scene/OSFall06.pdf

As we hovered above the scene, two of the victims appeared to be looking up at us, treading water. I hurriedly changed into my wetsuit when I heard the pilot say, ‘They don’t look like they are in any immediate danger. They can wait for the boat.’

I said, ‘No Sir, they look like they are drowning!’”

…

Coast Guard rescue crews are less likely to see a person drowning 

than nearly every other water rescue professional (beach and pool 

lifeguards). Our relative distance to the accidents and distress calls 

to which we respond usually puts us on-scene well after persons 

who may experience problems have done so.

I tried to explain to my wife once that beach lifeguards not only see more people start to down in the first 60 seconds, you also see more broken necks in the first 10 minutes that EMTs or some surgeons see in a lifetime. 

Greg, that's amazing.

Rohit, this article really stayed with me since last I read it. More notes:

http://pandawhale.com/post/20939/rescuing-drowning-children-how-to-know-when-someone-is-in-trouble-in-the-water-slate-magazine

Thank you for sharing this article today.