ok  it took a little effort, but I just happened to dig up an copy of Nuts N
Volts with a similiar project.  Look at the Oct.  1998 issue, in there is a
sonar project for remore control boats. Now this unit uses above water
Ultronsonic tranducers, but if you find and substitute  underwater
transducers,, you might be able to get in the ball bark with the information
here.  If nothing else, it might make for a good strart on the reasearch.

you might be able to get a copy of the mag from them or a least a copy of the
article. and the code may still be on their site, I did not check

Eddie, kc4awz


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