Every year people drown within a short distance of the shore. When some trauma happens, such as stepping off an underwater shelf, the surprise itself can cause a drowning response. Victims, even if they can swim, suddenly can not shout for help and just splash around in the water. Exhaustion can occur in a minute or less, and the person then quits splashing and sinks. Should you find someone needing assistance from shore, remember the following.
GO for help. Do not try to make a rescue by swimming to the victim unless you are a certified life guard. The drowning victim could grab hold of you and pull you down even if you are a good swimmer.