As Previously Stated, Those Who Exploit Acoustic Data Can Never Know Enough.
Those who exploit acoustic data to derive information additional to basic OPINTEL should either have a background in marine engineering or the acumen to know when it is appropriate to consult someone who does, i.e., ask the right person the right questions.
Here are two examples of what happens when that is not done.
A class of submarine was assessed to have a turbo-electric propulsion system when the motor needed to provide the required horsepower would have been too large and too heavy to be installed in the hull.
A class of submarine was assessed to have a propulsion system with a very detectable main turbine but extremely quiet reduction gears, an unlikely circumstance because the turbine and the gear were essentially one unit on the same isolation mount.