Rob21
ELTs will transmit when wet.
But when submerged, the radio signal would be significantly attenuated. At some minor depth unhearable by other airliners. ( And again xmitting on 121.5 or 406?? )
Off & still triggered by being wet? I could be wrong but I believe it needs to be set to the 'armed' setting. Off is off.
AstraMike, many long posts so I'm starting to skip but your #3179 was a good read.