One question here : Would it be realistic to be able to hear the thunder with the hydrophone while being submerged ? ... :06: Sorry to hijack this thread. Should I start a new topic on this subject ?

Good question, Mister_M.

I imagine that since the sound of thunder is in the form of a wave of sound pressure moving through the air, it would also move through water and be able to be detected by a hydrophone, although I expect the sound would be muffled.