Historical and in-game drawbacks of using active sonar
 

I bet i've read that in-game enemy warships react to your sub's active sonar, and that they react even if you ping some merchant vessel.

So my question is: what is in-game behaviour of enemy ships, pinged by your active sonar? And what would historicaly accurate (real life WWII) behaviour be?

First 40 seconds of this clip too obscure as an answer?
http://www.youtube.com/watch?v=1c2jp8WyXms

The only thing I can figure out of your answer is that enemy ships retaliate to your active sonar. But I'd like details: do they start pinging you back, do they approach your position, do merchants head away from your position, what would be historicaly accurate behaviour?

The reason I'm asking is that from my observations I couldn't figure out if and how did enemy react to my active sonar.

Forget how stock does it but unless you are repeatedly pinging escorts usually dont pick it up unless they are close and also depends on sonar conditions ie sea state etc.

I think it's best not to use active sonar in presence of enemy warships but at times(as in RL, read in many accounts where a single ping was used to confirm range) it may prove to be a necessity.I recall an instance where I did not not want to raise scope and risk it being spotting when getting in close to shoot at two tankers in a convoy.The nearest escort was closing but about 3000 yards to port.I moved the sonar to the estimated bearing according to the TDC from my last bearing , sent a single ping which returned with target at 1900 yards.I sent bearing and range to TDC from sonar and closed to 1200 yards, then without the scope(a freighter was on top of me, went to 80 feet) I fired a spread of 4 fish at one large tanker.Four fish hit(could hear them but not see since had external cam off) Then using sonar only fired two at what I believed to be the second tanker, scored one hit.Hours later when I came to scope depth, the tanker was dead in the water and listing to starboard, gave her a coup de grace and had two 10,000 tankers down.Ahh love American TDC and the PK.

Now, the ping did not alert the escort.All depends on distance, direction of the ping.I think if you directly pinged an escort or was in the general direction, it would detect you.

Do merchants ever respond to active sonar? I've repeatedly pinged a few, and they appeared oblivious...

Later in the war I believe that some larger freighters do have some sort of active sonar detection capability. I had them start zig zagging after using active sonar. Don't remember which mods I had at the time but no doubt one of the TMO mods. Also noticed that they also reacted to my boat if I got careless about speed and not having silent running on. Not very common but it did happen.

Magic

And if close enough, you can just hear it, cant't you? or that only applies when you're submerged? I should imagine that the crewmen of a freighter, specially being in lower decks, probably could hear the pinging of nearby active sonar.

OK, let's analyze the situation. It works the same way for radar.

Remember the last time you were being pinged by an escort? What did it tell you? It told you there was an escort out there. Hearing the ping get louder or softer told you whether the escort was approaching or receding.

That's what they know about you when you ping.

What do you know when you ping twice? You know their exact position, and their course and speed! Advantage you.

Same thing with radar. They know you're out there somewhere. You know where they are, and their course and speed. Advantage you.

If they already know you're out there you lose nothing with active sonar or radar. If they don't know you're out there you already have such an advantage that you should consider carefully before losing it.

I'm actually going to ask again, boring old me :up:: could merchant crewmen hear the pings from a nearby submerged sub? Being below deck and close to the hull, of course.

I have to fall back on my old standby: It's not what they could do that's important, it's what they actually did, and reports are always better than guesswork. It would make sense to me that they could, but I've never read one single account of anyone on a surface ship hearing a ping through the hull, so my inclination is to say no.

My point of view, also. I too never hear any tale about ship crewmen 'hearing' pings. Now in a submerged sub, that's another matter.

What about surfaced subs? It's hull would still be 90% below waterline. Would you recall any story about a sub crew hearing pings when on periscope depth, or coning tower depth, or something similar? Or only when properly submerged?