Sonar

[pickinthebanjo]

As I advance in my career I usually like to pick up the best sonar I can. When I catch ships that are unescorted I start pinging them until I have an exact range.
My question is this, can merchants hear the ping like a naval vessel can? I've never noticed that they could but it has been a while since I made it that far into a career to have sonar. Also how well does that sonar that gives range/speed work? I think it is one one the later models.