@robin, my dji phantom ran low on batteries and sank about 15ft to the bottom of a 10ft waterfall. I jogged about a mile back to my truck to get some googles (to locate then drone) jogged back and swam down and got the drone. the lights on it were still blinking. I took the battery out, oiled the motors and it was flying the next day. I trashed the battery because i didn't really trust it and with it being lithium ion i was kind of nervous about it....