I just died because I afked for 30 seconds while swimming on row boat. I only heard some ring that is the same as getting a quest. All it took was like 10 seconds on deep ocean for me to die, this is a joke honestly.
EDIT: there is absolutely no water difference in game as well. It looks like normal water. Can't even get some water from kitchen without dying...
EDIT2: Maybe even stop people from entering deep ocean on rowboat and canoe without a toggle.