cz-21

Just got back from vacation in Mexico. After leisurely hunt, $25 in coins (they use and lose a lot of 10-pesos coins there, roughly $1 each), a set of hoop earrings (amazingly, found both earrings in the water, within one foot of each other), an old toy soldier (gave it to the local), and my...

Sorry if this is a stupid question--I am a newbie; or if this has been asked before. I searched around and couldn't find an answer to my question: since water is a good sound conductor, can one use detectors, specifically Tesoro Sand Shark or Fisher CZ-21, while hunting underwater or...