When I was clearing Dragonsand I decided to try hiring the healer in the resort; I didn't realize he would revive all my dead characters. So after he did that I just walked out into the water to drown them all again. I found out that you drown just as fast with a thousand hit points as you do with 20. It appears that drowning takes a percentage of your hit points (or something) rather than a fixed amount.
I remember there being an old post about the level 0 water walking bug and I'm guessing there's an explanation here somewhere. 50 percent of zero is still zero, so whatever calculation drowning uses to reduce hit points must include a percentage of something (endurance?) which ends up making the end result zero.
