An interesting article in a US coast guard magazine caught my eye, about what a drowning person looks like. Bits excerpted below.

“Doesn’t everyone who works on (or above) the water as rescue professionals know what drowning looks like?
Most people assume that a drowning person will splash, yell, and wave for help; and why wouldn’t they? That’s what we see on television. Without training, we are conditioned first to think of drowning as a violent struggle that is noisy and physical. It is not.
[…]
This is not to say that a person in the water that is shouting and waving is fine and doesn’t need assistance. They are in what is known as aquatic distress. They are not drowning, but realize they are in trouble and still have the mental capacity (and lung capacity) to call for help.

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.”