Question about submarines and layer detection for all you submarine experten.

[Destraex]

A friend of mine asked this. I don't know what the latest tech does really. But those that play things like Command and that sort of thing may know. Any vets would be even better.

"I was wondering about the latest theories vis-a-vis the layer in submarine detection. If I'm in a sub and looking for other subs what are the considerations with the layer to maximise chance of detection of enemy subs while minimising self detection. I figure that as the chance of detecting the enemy increases so does discovery everything else being equal. If there's no surface ships above the layer is the go?"

[Pete Dero]

I'm no expert at all but I have been told :  Sub just above the layer and towed array sonar below the layer to increase chances of detecting the enemy.

If the enemy sub is hiding below the layer he will have a hard time detecting you while your sonar could detect him.  As you said if there is a surface ship now you are easier to detect.


Explained by Baloogan (member to the CMANO team)

larger playlist : https://www.youtube.com/playlist?list=PLgRuKky0mojb3THVzt27NXtbe63tDEiwN

[JasonPratt]

Drawing on my extensive experience reading Tom Clancy novels (and playing the original RSR game): another advantage to being over the salinity layer is that sounds bounce farther, ricocheting between the surface and the layer.

Of course that includes your sounds. So if a sub isn't in a hurry, the captain will sometimes slow down and rise above the layer to listen around, and then sink below the layer to scoot for a while.

[Destraex]

Hmmm. thanks.

Page 33 here is pretty good. But I am wondering if drones and all sorts of other things are used now.
http://www.matrixgames.com/forums/tm.asp?m=3418599

[Toonces]

The short answer is, all things being equal, if two equal subs are in the same body of water, putting out the same amount of noise with the same sensor and crew capabilities, then yes, finding the enemy is equal to being discovered as well.  It's no different than two co-altitude F-15s with AMRAAMs driving straight at one another.

It's typically much more complicated than that, obviously.  If you have two dissimilar submarines, then how you use the layer will depend on your own capabilities and limitations vs. your enemy. 

Also, not all layers are equal.  In JP's example above, sound could duct above a layer, bouncing along between the surface and the thermal layer...depending on the strength of the layer, the strength and frequency of the sound produced, the roughness of the sea surface, even the time of day.

So...there's no easy answer to your friend's specific question. 

[JasonPratt]

Thermal layer, salinity layer, one of those.  :-[

I suspect (though I haven't paid enough attention in years to know if this has started being used) that the Navy probably has something like a $50,000 military grade toilet float, that a sub can release (and draw back) like the tail, which carries a sensor 'tail' above the layer, like the tail trails below the layer.

[Toonces]

According to Google, a submarine can trail a towed array either above or below the submarine's depth, depending on the submarine's speed, and how much of its towed array it deploys.

[Toonces]

My original answer seems awfully unsatisfying.  Let me know if I can help more, Des.  It would help to know if we're talking a specific game or real life, as it probably makes a difference.

[Destraex]

Thanks Toonces.
I think my friend was just wondering what the latest defence industry thinking was on this subject.
He asked me directly but I have no idea what the latest tech in that area is. I just suggested they might be using drones and such by now. But I doubt command has anything the public don't already know about. I thought people here might be hooked in to how modern warfare patrols the different layers. What methods they use. I wonder if towed arrays are detectable anyways.
Just in general. But he does play command. So it may have prompted him.

[Yskonyn]

Towed arrays are passive sensors, meaning they just listen and don't send out signals. They are undetectable by active sensors.

[Destraex]

The Russians have developed sonar capable of detecting the cable and the towed array.... ok maybe not.
I do remember the Russians creating some sort of sensors that detect all sorts of things like the sense of smell ona dog for prey. I think they were rumoured to detect particles of pollution (submarine trails)in water. Don't know how trrue this is either.

[besilarius]

Talking about towed arrays brought to mind the SQS 35 Variable Depth Sonar.
https://www.globalsecurity.org/military/systems/ship/systems/an-sqs-35-gallery.htm

This was a 1970s piece of equipment that sonarmen loved.  It was deployed by cable and could get under thermal layers.  When Desron 12  was homeported to Athens in 1972, Manley and Barry had the system.
The biggest problem we had was NATO allies.  They were scared to death about an underwater collision, and it was very restricted in use.
The VDS worked well actively and passively.  On one occasion, Manley found a Charlie/Victor with the 26 sonar.  AFSOUTH gave us permission to deploy the 35, and we tracked that sucker for almost an hour in passive mode.
Then Italy got worried that one of their subs was in the area, and AFSOUTH told us to go active.  The protocal for that was to ping out VDS in morse code.  Thus warning anyone that there was a variable depth equipment deployed.
Well, we imagined that Soviet four striper probably swallowed his tongue when he realised he was being tracked.
He went under the layer, and the 35 went below with him.  IIRC we stayed with him for another forty minutes or so.
But he was sharp.  A fat merchant stumbled  along, and the C/V went under him.  In the turbulence, he dived deep, went silent, and we couldn't regain contact.
If we could have loitered long enough, we might have picked him up, but there was some assignment and Manley had to leave after a few more hours.

[Destraex]

Wow. Love the story. Interesting.
I assume you served on a sub or is that an extract from somewhere else?

[JasonPratt]

Towed arrays are passive sensors, meaning they just listen and don't send out signals. They are undetectable by active sensors.

Unless they drag on the bed, and then passive sensors will hear them. ;) (Sub officers take steps to avoid that I'm sure.)

[besilarius]

No,never did more than pass through a sub, during a middie cruise.
SWO all the way.