Question about towed arrays

[Sea Demon]

In any platform, does it make any difference if I stream the towed array out just half-way? And I mean in sensor detection capabilities. Or do I need to stream it all the way out for maximum effectiveness?

The reason I ask is because I have often needed to retrieve the sensor so I can do torpedo evasion by maximizing my speed. And it often takes too long (especially in 688(I)) to do it and still have enough time to properly evade. Most of the time that I stream it half-way gives me enough time to get it back in and still evade. I hate evading a torpedo successfully, and then have a broken TA and no way to stream the other one.

What do you guys do?

Sea Demon

[OKO]

you never broke the TA on 688i and Akula even a maximum speed.
On Seawolf, you will break it only above 38 knts.

So you don't need to retract it at any time.
Not only it's a waste of time, but also you will lost all your contacts.

My advise : let it ENTIRELY deployed ALL the time.

Streaming the TA half way won't change the sensor capabilities, it will just make the TMA more difficult, because triangulation will be less effective.
If you play with manual TMA, you better never retrieve half way the TA, or you will simply have much more difficult job.

So, there is no reasons at all to retrieve the TA, no realistic reasons, and no virtual reasons.
It should be always deployed at full length, EXCEPT on shallow waters, to avoid dragging the bottom, that's all.

[LuftWolf]

Compressioncut told me that the SQR-19 depth actually is modelled in the acoustics engine, so I'm pretty sure if you wanted to regulate its depth, the most effective way would be to use a combination of speed and TA length.

However, I didn't even know that depth was modelled in the acoustics engine for the TA's (a misreading on my part of the manual) so I think a skimmer captain can give you much better information on this.

In terms of the subs, if you have to do a series of maneovers and you don't want to wait for the TAs to come around, in those circumstances you might want to only let it out halfway, but that, as OKO said, has to be weighed against the reduced effectiveness of TMA information.

[OKO]

Originally Posted by OKO

So, there is no reasons at all to retrieve the TA, no realistic reasons, and no virtual reasons.
It should be always deployed at full length, EXCEPT on shallow waters, to avoid dragging the bottom, that's all.

oops ... that was right with DW stock
but need to be checked with MOD 2.01, where TA are much longer than with DW stock ...

[LuftWolf]

Well, PD (he provided us the information and the pre-testing) increased the lengths of the TA's: Pelamida 301m to 701m and the TB-23/29/SQR-19 to 5000ft from 2500ft, the correct and current length of the TB-16.

Periscope Depth has been playing with these mods to his personal DB for sometime, so I'm fairly certain he hasn't noticed any problems, at least he hasn't mentioned any.

The game models the TA's as being the same depth along their whole length, so I'm not sure, other than drift from ocean currents, if the length is going to influence TMA directly.

[Sea Demon]

Originally Posted by OKO

you never broke the TA on 688i and Akula even a maximum speed.
On Seawolf, you will break it only above 38 knts.

That's true. I mostly drive the Seawolf SSN when I'm in the submarine mood. And that's where I saw the failure. I only assumed it would happen on 688(I) as well. So I modified how I did things to reflect it in that sub. I guess 38 & 40 knots is not that much of a difference in running speed anyways. I knew my question was kind of dumb. I just wondered what some of you other sub drivers did. Thanks for your answer.

@ Luftwolf - Thanks for your advice as well. I'm assuming I can get the TA around quicker too with a higher tactical speed. In the Seawolf that is pretty easy to do. It sounds like the only reason I should limit the length of my TA in an ASW mission is for shallow water ops.

Sea Demon

[SeaQueen]

Originally Posted by Sea Demon

In any platform, does it make any difference if I stream the towed array out just half-way? And I mean in sensor detection capabilities. Or do I need to stream it all the way out for maximum effectiveness?

Varying the length of your tail can be very useful. It allows you to fine tune your sonar performance for the environment, so that you can always keep your towed array at it's best depth. That can have a big impact on your detection ranges, or even your ability to detect someone at all!

For example, suppose you are in a surface duct, you want your tail to be somewhere in the middle of the duct, below the sea surface noise. One way to control your towed array's depth is to speed up or slow down. Slower means deeper, but since the tail is very long, you don't want to put it too low and miss the fabulous surface duct. Faster means you might be able to keep it in the duct, but you get more flow noise, compromise your own stealthiness and blind yourself. So you don't want to go too fast. The solution to this problem is to stream or shorten the tail accordingly.

What do you guys do?

I drive through the ocean, dropping BTs all over the place, figuring out how to make the most of my sonar, and adjusting my tail and speed. It's not an exact science. You don't have to always keep your towed array RIGHT AT a particular depth, but a good guestimate of about where it needs to be, and then getting it in the right ballpark is fine. You'd be surprised how much your sonar performance can improve this way.

[OKO]

Originally Posted by Sea Demon

It sounds like the only reason I should limit the length of my TA in an ASW mission is for shallow water ops.

Sea Demon

No doubt about it with stock DW. No question, that's the right and only thing to do.
lengthening or retrieving the TA with stock DW is a total waste of time and will give you lots of problem on TMA.
Only people using AC TMA didn't saw that ...

BUT with 2.01, we have to check the comportment of the TA with new length, much longer than before.
So, hold on, you will have some news about it soon

[OKO]

OK, on first quick tests with 2.01 TMA, it looks like nothing change.
Or only a VERY thin change
You are able to make a TMA with less than 500m of error at 20 km with Akula at 7 knts with 3 good LOBs of TA and SA merged.
this mean the Akula can work on TMA at 7 knts with 2.01

oufff
I think the fact you lengthened the TA compensate for the problem of TA falling down.
Just because the triangle have a much larger base (distance beetween your ship and the TA), this give you best accuracy on triangulation.

And anyway, I think (but not sure) that the TA doesn't fall deeper than with stock at 7knts.
Looks like the TA is hydrodynamically configured to saty at the same level of the boat from 7 knts.
that's very nice.
I will test now TMA on TA only

[OKO]

With TA only, I could find a solution 1 km closer from the real thing at 20km with 6 clean LOBS with akula at 7 knts.
Looks like everything is ok here.
A bit less accurate than before, but anyway absolutly usable to engage.
On this test I could understood the TA fall a bit deeper than before because of new length.

[OKO]

Originally Posted by SeaQueen

Varying the length of your tail can be very useful. It allows you to fine tune your sonar performance for the environment, so that you can always keep your towed array at it's best depth. That can have a big impact on your detection ranges, or even your ability to detect someone at all!

For example, suppose you are in a surface duct, you want your tail to be somewhere in the middle of the duct, below the sea surface noise. One way to control your towed array's depth is to speed up or slow down. Slower means deeper, but since the tail is very long, you don't want to put it too low and miss the fabulous surface duct. Faster means you might be able to keep it in the duct, but you get more flow noise, compromise your own stealthiness and blind yourself. So you don't want to go too fast. The solution to this problem is to stream or shorten the tail accordingly.

I drive through the ocean, dropping BTs all over the place, figuring out how to make the most of my sonar, and adjusting my tail and speed. It's not an exact science. You don't have to always keep your towed array RIGHT AT a particular depth, but a good guestimate of about where it needs to be, and then getting it in the right ballpark is fine. You'd be surprised how much your sonar performance can improve this way.

Seequeen, you are talking about detection here.
But not about TMA.
You won't do any TMA this way, except if you let the magic AC TMA working of course.

On more very important trick for detection (if not the more important) => using good SNR zone.
Where do you find them ?
easy, they are the darkest zone on the map.
To understand what I'm talking about, press CTRL+I during a game.
Darker zone are the place where you have the best SNR, bright zones, where you have poor SNR (so ... bad for detection)

There is sometimes HUGE difference on SNR, depending on the area.

[OKO]

Originally Posted by OKO

With TA only, I could find a solution 1 km closer from the real thing at 20km with 6 clean LOBS with akula at 7 knts.

With 9 LOBS, I could find a solution with less than 500 yards of error at 20 km.
That's logical, the more the LOBs (with one array only) the best the accuracy.

Everything rocks with new TA length !!

[OKO]

I made a little movie to show a TMA with TA only on Akula with 2.01

=> http://okof4.free.fr/fichiers/DW/TMAakula_TAonly.avi

actually uploading, ready in 30 minutes from this post

[LuftWolf]

Everything rocks with new TA length !!

Good to hear, thanks again OKO!

[XabbaRus]

Altering the length of the TAQ will have an effect on how well the TA performs and how far it picks stuff up.

Thoms found that out when doing the SCX database and since it is a quie a neat thing I doubt SCS removed it from DW so yep it does and has various tactical implications.