Using Active Sonar

[The Bellman]

Some interesting observations here:-

http://www.subsim.com/phpBB/viewtopic.php?t=45381

[Molon Labe]

Here's the short version of the thread: In the current version of DW (1.01), there is an audible return for any object within the sonar's display range, regardless of the strength of the return or the background noise in the water. It's a very big bug in the game, and there isn't much you can do about it. It was mentioned that 1.02/3 takes care of this problem.

So, what does this mean to you, the sub driver?

Well, first off, it means that any FFG (or really, any surface warship with active sonar) will detect you with active sonar at 20kyd, whether player controlled or AI. This is especially important if you're driving a Kilo, because at 20kyd, your torpedoes will not be able to reach him if he runs for it. In order to get a good shot, you have to close in while he tracks you... and sends in the helo, or calls the Orion, or tells a nearby sub to fire an ADCAP at you.

It also means that a sub player can locate any other sub using active sonar, up to 80kyds IIRC. At those extreme ranges, there will be no visual mark on the display, but there will still be an audible return at the correct range. The player can just mark every bearing at that range until a contact is created. Again, this is very significant if you're in a Kilo (or in a sub and playing against one). The opposing SSN can use the active sonar to find the Kilo from outside of the Kilo's torpedo range (or even from outside of missile range), and attack it with impunity.

Now for the good news. The LW/Ami mod makes significant changes in this regard. The database changes make it possible for a sub to get within the max display range an not produce an active sonar return, depending on the acoustic conditions and the aspect angle of the sub (the side of the sub produces a larger return than the bow or stern). There will probably still be cases where there is an audio return before anything can be seen on the screen, but since the range at which the audio return is created is dependent on factors other than the size of the display, this isn't a big problem. Some commented in the thread linked above that it may even be realistic. (Also, since the mod increases the range of the Klub-ASW, an SSN will not be able to attack from outside of the Kilo's missile range.)

[Molon Labe]

Okay, so when should you actually use active sonar?

Generally, active sonar searches are a bad idea for subs, because a sub is supposed to remain hidden. Any other sub will hear the ping and will know that you are present, what your bearing is, and approximately what your range is. If there are two opposing subs, they will be able to triangulate your exact position and attack immediately.

There are times when active sonar makes sense, though.

As mentioned above, in stock DW 1.01, if you're in an SSN and you're looking for a Kilo, your best bet is active sonar. You will be able to detect and engage the Kilo from outside his weapon range.

Also, if you are relatively certain that the enemy already knows your location (for example, because you haven't detected him yet but you just had a torpedo shot at you), then you aren't hurting yourself much by going active. An active ping in that case can tell you exactly where the incoming shot came from, allowing you to fire an effective snapshot.

If your torpedoes are nearly on top of your target, an active ping can help you pinpoint the target for terminal homing. You can even mark his decoys and avoid them. The information given to the enemy in this case is significant (since he should be evading and therefore does not have your current bearing on passive sonar), but if it leads quickly to a kill it won't matter.