[bruschi sauro]

Originally Posted by Gildor

I am not an expert with Naval sensor terminology, but I was under the impression that SONAR and HYDROPHONES were not the same thing.

Isn't sonar the sensor to determine range to a target with a non-passive sound "ping", whereas the hydrophones are a passive listening device? i.e. two different apparatus.

Or am I completely off base here?

no you are right