HELP!.. Does this kind of Transducer Works Underwater?

[fordelon1]

http://www.ebay.com/itm/Waterproof-Ultr ... 0721354139

or this
http://szblj6868.en.made-in-china.com/p ... 125H-.html

can it be submerged and determine the depth of water, much like how fishfinder works..?

Thank you for replying

[Rover]

Ultra sonic transmitters do not work underwater. For water use, they typically use sonar. (same is true for fish finders)

Rover

[Seawolf]

The ebay one has potential, but you have to put it in some sort of waterproof enclosure. Range is going to be limited, but I saw accurate ranges of up to about 30 feet with that one. Separating the signal from the noise turned out to be hard though.