Drowning's not like the movies....
With beach and pool season opening, it's worth re-reading Slate's account of what real-life drowning looks like. People in trouble often never have a chance to thrash, wave or scream; they slip under the water quietly and never come back up.
http://www.slate.com/articles/health_and_science/family/2013/06/rescuing_drowning_children_how_to_know_when_someone_is_in_trouble_in_the.html