Put Urine On A Jellyfish Or Stingray Sting To Ease The Pain!
Do not do this unless you want it to hurt more. It's unclear how a rumor like this gets started, likely a disaffected oceanography student or vicious pro-urine propaganda from the jellyfish lobby. Either way, don't do it.
So what you're saying is that you always have to go when around jellyfish.
radar DOES NOT DEPEND on sight - you dont "see" except on your screen - radar is based on "sound" NOT "sight" - day or night - radar works.