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-   -   Was the towed array really that better? (and more questions) (https://www.subsim.com/radioroom/showthread.php?t=254002)

drEaPer 11-10-22 06:30 AM

Was the towed array really that better? (and more questions)
 
So I played through the campaign of 688 Hunter/Killer and then I continued to play Sub Command.

And I got some questions, cause things change between the two.

First of all, I find the waterfall display in 688 more realistic. The dots and paths drawn across the watterfall are more broken up, look more organic, like little sounds hitting the hydrophone, while in Sub Command, you always have thick lines that look binary, as in "Line here: Yes/No".

Did the sonar model change between the two games?


The second question would be about the towed array. In 688 the spherical array was also good to detect all kind of contacts, even enemy subs.
In Sub Command, it is pretty straight forward: The towed array is ALWAYS more sensitive, and ALWAYS picks up a contact before the spherical array does.
Basically the towed array is your main sensor.
That also seemed to change between the games. Is that realistic?

Lastly, I noticed that values changed, in 688 the ownship's crush depth is about 2000ft, while in Sub Command it's about 1600ft.
Why did that change?

Did 688 use data that is to close to classified data, and someone went: You cannot do this, or was 688 H/K just way off and had bad guesstimates and Sub Command is closer to reality?

Cheers!

Aktungbby 11-10-22 11:47 AM

Welcome back!
 
drEaPer!:Kaleun_Salute: back on the surface after a 9 year 'silent run'!:up:

drEaPer 11-10-22 04:23 PM

Yeah, after food ran out, we used the tubes to send the seals out fishing underwater, though mutiny was starting to rise after 8,5 years of eating seafood, so I was forced to set a course home.

ET2SN 11-10-22 08:07 PM

Just chalk it up to "newer software". :Kaleun_Thumbs_Up:

Sonalylst's tended to "upgrade/evolve" their games based on newer info and things that wouldn't get them in hot water with the Feds.

FPSchazly 11-10-22 10:43 PM

Quote:

Originally Posted by drEaPer (Post 2837169)
So I played through the campaign of 688 Hunter/Killer and then I continued to play Sub Command.

And I got some questions, cause things change between the two.

First of all, I find the waterfall display in 688 more realistic. The dots and paths drawn across the watterfall are more broken up, look more organic, like little sounds hitting the hydrophone, while in Sub Command, you always have thick lines that look binary, as in "Line here: Yes/No".

Did the sonar model change between the two games?

The second question would be about the towed array. In 688 the spherical array was also good to detect all kind of contacts, even enemy subs.
In Sub Command, it is pretty straight forward: The towed array is ALWAYS more sensitive, and ALWAYS picks up a contact before the spherical array does.
Basically the towed array is your main sensor.
That also seemed to change between the games. Is that realistic?

Lastly, I noticed that values changed, in 688 the ownship's crush depth is about 2000ft, while in Sub Command it's about 1600ft.
Why did that change?

Did 688 use data that is to close to classified data, and someone went: You cannot do this, or was 688 H/K just way off and had bad guesstimates and Sub Command is closer to reality?

Cheers!


Well, to speak to the waterfall, 688(I) H/K has a potato resolution of like 640x480 so I'm fairly confident the way it's drawn is a consequence of 90s resolution/processing power more than anything. I would expect the signature of a ship going constant speed to be a bright, solid line on the waterfall. You have constant flow noise, constant power plant sound, a spinning screw. When a car drives by you on the road, it makes a continuous sound. Though, of course, some things can vary.

The sphere/towed question is a good one. All else equal, low frequency sound travels the furthest, and the towed array is tuned for low frequency sound. The spherical, on the other hand, is tuned for medium/high frequency sound. The higher the frequency, the shorter the sound goes (all else equal of course). Now, the towed is a line array whereas the spherical is an enormous (relatively speaking) ship-borne array. How that plays into which picks up a track first is a good question. But the towed is quite a mixed bag in 688(I), so I will lean towards the towed should be more sensitive like in Sub Command because the towed has some major drawbacks. You can't use it in shallow water or with extreme maneuvering, so the fact that navies put up with the difficulties of towed arrays means they must have some strong advantages, i.e., pick up tracks first.

Now, IMO, the real weird sonar behavior in 688(I) is the broadband picking up tracks before the narrowband. That goes completely against what I know as the whole point of narrowband: in the ocean, it's easier to pick out specific frequencies of sound (narrowband) than general noise (broadband), so narrowband should pick up stuff first like in Sub Command and Dangerous Waters.

As to the crush depth thing, yeah, avoid some suspicions from the feds plays into it like ET2SN said. I imagine all three Sonalysts games have different values for the crush depth that are more or less within ~30% (engineering rule of thumb) of the real crush depth. For insights into what the crush depth may be, you can look up the depth that the Thresher imploded. Based on that, it wouldn't surprise me if all the game values are underestimating.

ET2SN 11-11-22 05:15 AM

Yeah, "crush depth" and "test depth" are some pet peeves for me. :03:

Without getting into trouble, I kind of blame Tom Clancy for making them sound so important. What's more important is figuring out a good "working depth" where you aren't wasting HP air or blowing out watertight seals.

Think of it like this- if you own a Corvette are you always going to drive it at 140 MPH? In that same reasoning, what's the deepest you have to go so you don't cavitate at a Flank bell? Why do you need to go deeper? :hmmm:

magicstix 11-12-22 06:14 PM

Details are always going to be classified, especially on boats still in service like the LA class.

But what is commonly known is that towed arrays outperform bow arrays in general because of simple physics.

Bow arrays are mounted on the ship and at the front. They have to deal with flow noise and ownship's own acoustics.

Towed arrays are towed a mile behind ownship. They aren't at the "cutting" edge of the flow and they aren't near a super-loud noise source (namely ownship), so they're going to be more sensitive.

The downside is because they're line arrays, they can't tell left from right, and they become unstable when ownship maneuvers, so even though they're more sensitive, they have their limitations.

Long story short: Yes, it's more realistic for towed arrays to do better.


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