Can the submarine hear the sound of a helicopter? If you can, why don't we see the helicopter's icon on the CW's tactical map?

[lilongfei_shanghai]

Can the submarine hear the sound of a helicopter? If you can, why don't we see the helicopter's icon on the CW's tactical map?

[strykerpsg]

You can definitely hear the sound of the nearby prop/jet/rotor wash if they are low and close enough. I understand that to be a realistic portrayal of modern passive sonar suites.

As for populating on the tactical map, I don't think that would be very accurate to portray, since the aerial target is often moving too fast to triangulate the general area needed to begin an initial solution of it's bearing or fix.

[rokvam]

Originally posted by strykerpsg:

You can definitely hear the sound of the nearby prop/jet/rotor wash if they are low and close enough. I understand that to be a realistic portrayal of modern passive sonar suites.

As for populating on the tactical map, I don't think that would be very accurate to portray, since the aerial target is often moving too fast to triangulate the general area needed to begin an initial solution of it's bearing or fix.

Correct on both accounts...

[Racer D]

Incorrect as a helo dips its sonar which takes a bit of time and is stationary for this amount of time. Maybe 45 - 60 seconds? More?

If you can get a bearing on instantaneous events such as a launch transient then you can get one on 45 seconds of sonar dipping.

So it would be nice to know where it is dipping.

[rokvam]

Originally posted by Racer_D:

Incorrect as a helo dips its sonar which takes a bit of time and is stationary for this amount of time. Maybe 45 - 60 seconds? More?

If you can get a bearing on instantaneous events such as a launch transient then you can get one on 45 seconds of sonar dipping.

So it would be nice to know where it is dipping.

As always we over estimate the submarines abilities in the sonar departement.

Sonars, and fire control systems are fantastic in their own right, and a submarine is the perfect platform to get the most out of different types of hydrophones. But all systems have their limitations.

Sensor and computers have come a long way, since my time in the sonar shack and manning the fire control computer, but getting an accurate fix on a hovering helo is not as easy as one should think.

Hearing them is one thing, but getting their exact position based on sonar sollution only... No way!

The best way to spot a helo and know where it is on the map, would be by visual tracking via the periscope. And that sir, is risky business...

I'll grant you we could get a marker on the map after visual contact. But not based on sonar bearing data only.

[Julhelm]

I guess it's because we never draw passive sonar bearing lines like you may be accustomed to from SH series.

Rokvam, what sub were you on?

[rokvam]

Originally posted by Julhelm:

I guess it's because we never draw passive sonar bearing lines like you may be accustomed to from SH series.

Rokvam, what sub were you on?

I sailed for 10 years as a sonar & weapons officer on the Ula class submarines in The Royal Norwegian Navy.

I also had a brief spell sailing the Kobben class, that preceeded the Ula boats.

We did patrols in the Barents sea, and I have listened to many of the ships and subs in your fantastic game on sonar :-)

By the way, if a helo is pinging you with his active sonar, then you might be able to work up a sollution, but focus would be on pressing the attack, and staying hidden, as you don't have any weapons to take out the helo with... The helo is not the target... The Ropucha is :-)

[rokvam]

In my time on subs, we had a computer program that enabled us to calculate the distance to an active sonar pulses.

This could to some extent be used to get the position of a pinging helo, but it would not be completely accurate.

Anyway that was not our focus.

Truth be told, when a helo goes active, he suspects some thing is lurking below.

They will be searching with passive bouys first and formost. And that's when they are most dangerous, because you can inadvertantly run in to a pattern of passive bouys, and give your position away.

[rokvam]

Another touch that would be nice:

Lines to give you bearing to helo's going active with dipping sonar. Like when surface ships and subs go active.

Also, unless a bouy is active (goes for both the ones dropped from ASW aircraft and helos), we should not be able to see them on the tactical display.

I constantly get the little flowers on my display, showing me where the ASW planes drop their bouys, but I can't say I have heard them pinging.

Unless that bouy is active, you won't hear it, unless you are very close when it hits the water. Even then, that little splash would not be sufficiant to give you a fix on the bouys exact position.

[Julhelm]

Those are active bouys. Only the dipping sonar gives the yellow bearing lines.

[rokvam]

Originally posted by Julhelm:

Those are active bouys. Only the dipping sonar gives the yellow bearing lines.

But I can't recall those bouys giving of sound... In the missions I've played I have seen plenty of those markers on the map, but no sound... Am I wrong here? Are they active in the game mechanic, but without the audio?

[strykerpsg]

Great feedback rokvam. Always enjoy the actual real world end user's input.

[Racer D]

But you said you could hear a chopper.

If you hear it you can get a bearing, right?

And if you hear it and it is dipping and thus stationary...?

I mean you said you could hear a chopper...

[strykerpsg]

Originally posted by Racer_D:

But you said you could hear a chopper.

If you hear it you can get a bearing, right?

And if you hear it and it is dipping and thus stationary...?

I mean you said you could hear a chopper...

Speaking off the cuff here, as I was not a navy guy, but read tons of fiction/non-fiction to understand the capabilities enough, allow me to explain...

What you are saying, in theory should be correct. If the aircraft, helo in this case, hovers long enough and is close enough to detect the rotor wash, yes, it could generate a bearing. However, that helo is not going to be stationary very long because if equipped with a dipping sonar (not all have dipping sonar), then it needs to allow the sonar device to travel to various depths to get passive or active feedback. Dipping sonar is also limited to the length of cable on the spool, not to mention weather conditions.

So, it would dip, above and below the thermocline, listen for a few moments at each depth, then retract it's device and relocate. That initial contact will then become stale and eventually drop off. While I suspect a good sonar person would certainly let the presence be known of an nearby ASW airborne asset(s), it most likely would nto make much sense to plot it because it will move at a high rate of speed, on a direction unbeknownst to the sonar crew. Ships and subs however, move at a trackable and calculated fashion, thereby generating a fix. The ships and subs will not just up and jump to a new spot on the plotting chart as a helo would or could, therefore makes sense to track, identify and make a firing solution.

Now, as mentioned, I was not a navy guy (rather army) but understand the basics of CIC operations and sonar to understand the challenges of trying to track a helo.

[Racer D]

But if bearings of hovering helos are called and all are to starboard, I will not steer to the right for a while...

If they are all around me, then I know I have to lay low for a while.

If they are ahead of me, might as well turn back a bit...

[strykerpsg]

But I think you are assuming your sonar will pick up all helo and air contacts? Correct? That's just not going to happen. Bottom line is you either have depth and distance to your advantage or you are evading like crazy to break contact. One would always enter the fight as stealthy and deep as possible because you may not always know where the dipping helo is, or for that matter, the passive sonobouy laid by the helo or ASW aircraft and they are now triangulating your location without your knowledge, using the subs passive dipping sonar. If you are below 500 feet, you're most likely masked from any potential MAD gear.