Personally I don't think drowning is as bad as some people think it is. I think it's much much better than shooting or jumping will ever be. See normally when someone puts a bag over their head carbon dioxide builds up in the body because the bag blocks it from releasing. Carbon dioxide is what gives the feeling of panic and suffocation, not the lack of oxygen. Think about it, would the carbon dioxide release underwater? Probably yes, which means that you shouldn't get the fear of suffocation if that carbon dioxide is released into the surrounding water. Also i think it would be much easier to let go if one were to wear themselves out first. Meaning go running as much as humanly possible then jump into the deep end and it should be much easier for one to let go and surrender.
Personally I love water, in fact I loved it so much going swimming that I almost drowned twice. LOL OK I said it in a funny way but I did almost drown.
There are many deep pools open now that summer is here, all that is preventing someone from drowning is a fence. Most painful part is probably the psychological part of it, not so much the pain itself if there is pain. I've even heard that drowning can be euphoric too.
en.wikisource.org
"In the first place, it is to be remarked that persons who have come so near drowning as to be unconscious when taken from the water, and so must have passed through all the suffering that attends death by drowning, say that they remember no feeling of pain whatever. "