The question, drowning a peaceful way to go is for me an easy answer. Back in my preteen days I used to swim all the time, was pretty good at it and so when a friend asked to go along one day I said sure. I didn't know he couldn't swim, though I do now.
So I jump in and start swimming out and he's a bit slow getting started but tries. Soon he hollers for help and I know I'm the only one there to help so falling back on the YMCA training I knew I had to get to shore and get the stick I had there to save him. Well I didn't know he moved under water far from where he was and in my attempt to stay clear of him to avoid being caught I ended up getting caught anyhow. He normally was much weaker than me, but this time around he was as strong as a bull and I could not break free, I tried to knock him out, kick him, bit him, nothing worked. I will remember to my dying day the things I felt and saw. You see the bubbles going up to the surface, you feel helpless, yet you struggle on because you want to live.
To me drowning has to be the worst possible way to die, I certainly see nothing peaceful to it. Near the end I did give up and accepted the fact I was going to die, yet by chance my friend passed out first and I had enough air in my lungs to get me to the surface and pull him to shore where I helped him. It's not something I care to repeat because I was within seconds of dying, and yes after I gave up it did calm down, or so it seems. Up until that point it was a fight for life and certainly not peaceful.
The reason it was close was he did the classic climb the tree bit and had me in a bear hug, which I tried to avoid by swimming away from where he went under. He would climb up my body pushing me under, every so often I'd catch a small breath and would be able to struggle. The YMCA classes back then that taught you how to swim also taught you how to avoid being drowned, but not what to do once you're caught. My one and only experience with near drowning and that's why I know it's not peaceful.