I just went white water rafting with a bunch of friends in Malaysia - and on the boat were 2 other folks that were not great swimmers. We were in pretty good rapids, and the odds were for us flipping at some point. We were all wearing lifejackets, but in the rapids at times it feels like you aren't floating much at all.
The first patch of rapids another boat flipped and a bunch of people clutched on to each other basically climbing the ladder on each other - we quickly got to them but they all had swallowed a lot of water.
I gave a big speech about how if someone is drowning their instinct is to grab you and pull you under - so make sure when helping others you can safely just grab them.
A few rapids later we flipped. I quickly grabbed on to the raft and was doing fine - until I saw one of the poor swimmers floating face down drinking a lot of water and heading towards more rapids. I swam over and grabbed on to her, flipped her on her back and told her to relax we were going to be fine. Then we hit some more rough water and all of a sudden she was pushing down on my shoulders and I was under water for about a minute as we passed through rapids and she was struggling to stay on top of me. I outweighed her by 50 pounds and still struggled to get out from under her while being tossed around in the water. I was comfortable for the first 30 seconds or so, but at that point I started to get the whole "Damnit, I am drowning" feeling. I finally separated myself from her, threw up a few times, and then held the top of her lifejacket from a behind.
My long winded story is intended to say one thing. If someone is drowning, their natural instinct will be to climb on top of you to get above water. It doesn't matter how much bigger you are - how much better of a swimmer. Even if you are really experienced it can still be difficult to rescue a drowning swimmer.
