As they said in Scouts, "Reach or throw, dont go" as there is no reasoning with a person who is drowning and in a panic to get air/stay afloat, they will push you under.
That is why lifeguards have rescue floats (ie: Lifeguard Float ) as they can push the float to the drowning person and the person holds onto it while they pull from a safe distance with the rope.
Aaron Z
Also many very sad stories about people who drown trying to save others. Just on the news today in fact:
Teenage Girl's Body Recovered From Foam Filled Big Sioux River
The overwhelming impulse to save a loved one can unfortunately trump good judgement.