Join Date: Jan 2008
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You can try a bowl of water under the boat to refect the sound waves. There is considerable loss at the trasducer/air interface, but it does work some of the time.
The depth reading will be incorrect due to the speed of sound in air rather than water, so a correction factor (which I forget) needs to be applied.
If it does work you can be confident that everything is working as it should be before launch