Sonobouy ranges

[swimsalot]

Maybe some of the more experienced guys can offer some help here.
I have 1.01 with LWAMI 2.03.
After installing 2.03 and reading about the changes to the sonobouys- from the read me: THIS REPRESENTS A SIGNIFCANT GAME-PLAY CHANGE. To better reflect the way different sonobuoys are utilized in actual practice, the VLAD Shallow has been given the depth of 800ft, and the VLAD Deep has been given the depth of 1200ft, to prevent the use of VLAD’s in shallow water, as is realistic. The DIFAR buoy (90/400ft) MUST now be used in shallow water in the game, as it is the preferred buoy for shallow water operations in the real world. You may also want to take DIFAR Deep buoys along if you feel there may be a shallow surface duct and you want to have a good above-layer passive buoy option, that is a personal player preference. The DICASS Deep has also been given the depth of 600ft, to give an under-layer option for medium to shallow surface duct environments. Be aware, that this will change the game-play balance further in the direction of submarines for littoral operations, and possibly slightly in the favor of air-platforms in open ocean operations, given the option to put VLAD’s under layers in deep waters. Just remember NOT to load any VLAD’s if you are going to be operating in water that is shallower than 800ft. New buoy depths at a glance:
DIFAR 90/400
DICASS 90/600
VLAD 800/1200
I decided to run some tests to see what I need to do differently now.
I ran Beer's P3 Training Missions.
Noticed problems in mission 2, Barrier search for an Akula 2.
Akula is transiting East to West at 12 knots, 300 feet.
Conditions show a mud bottom, "bottom limited sound propagation", depths around 10k feet.
BT probe shows a linear line gradually rising from bottom left to top right of screen. (not sure what that means, but didnt look like a hard layer.
I turned "show truth on", then layed groups of bouys in front of the Akula's path.
Clusters of 4 bouys, 1 each of Difar S, Difar D, Vlad S and Vlad D.
These were tight clusters (bouy drop sounded like a machine gun), total of 3 clusters with 1000 yards between groups.

The Difars never turned "hot" even at 550 yards.
The Vlad Shallows and Deep both turned hot at 750 yards, only 1 VLAD shallow actually showed a "dot" on the 50hz line, this was at 550 yards. All other screens remained blank throughout.
Tried Autocrew, it picked up contact from the single Vlad Shallow, same thing I saw, at about 600 yards.
Repeated evolution again with second bouy line, same results.
Similar results in other missions, including MP6 and MP7 from Subguru.

Is the detection range for the Akula 2 at 12knots now 700 yards or less for VLAD, and apparently less than 500 yards for the Difars?

Could someone else look at this ?

Thanks guys, kinda frustrated here,
Swims

Edit* In the Minelayer mission, I was able to pick up an Akula speed 18knots at what I would comnsider "normal ranges", about 2.5nm on all bouys.
So if the Akula is at 12 knots it's inaudible at 500 yards, but at 18 its loud enough to hear at 4k yards???

[SeaQueen]

Originally Posted by swimsalot

BT probe shows a linear line gradually rising from bottom left to top right of screen. (not sure what that means, but didnt look like a hard layer.

There's not one. There doesn't need to be any duct at all in the ocean. Ducts are actually unstable features.

While the "bottom limited" ssp you see is actually an isothermal shallow water duct ssp and is totally non-physical for 10k deep water, the sim seems to model the approximate behavior one would expect from an actual bottom limited environment.

"Bottom limited" means that the speed of sound is higher near the surface than it is at the bottom. That means the the sound paths are bent down into the bottom. Depending on the bottom type, and the frequency of the sound, this can be a bad thing. If the bottom is muddy, then most of the sound will be absorbed. Other bottom types are more reflective and you can get a "bottom bounce" which is a little bit difficult to do TMA on because it's hard to come up with a good first guess about ranging, but it gives you better detection range.

The Difars never turned "hot" even at 550 yards.
The Vlad Shallows and Deep both turned hot at 750 yards, only 1 VLAD shallow actually showed a "dot" on the 50hz line, this was at 550 yards. All other screens remained blank throughout.

That sounds about right. So now... when you plan what you're going to do, and you see similar acoustic conditions, you know to use VLAD shallows and expect the bad guys to be about 550 yards away when you first see them. You can also plan on a search width of about a half mile and use that to make it impossible for anyone to get away from you too.

Is the detection range for the Akula 2 at 12knots now 700 yards or less for VLAD, and apparently less than 500 yards for the Difars?
...


Edit* In the Minelayer mission, I was able to pick up an Akula speed 18knots at what I would comnsider "normal ranges", about 2.5nm on all bouys.
So if the Akula is at 12 knots it's inaudible at 500 yards, but at 18 its loud enough to hear at 4k yards???

Although I haven't played the minelayer mission, this variability is realistic and probably due to the differences in acoustic environments. In sonar, there's not really a "normal" detection range. There's a "normal" detection range in a certain environment. The more you're able to use your knowledge of the bathymetry, the SSP, and your target, the better your estimate of how far you can see with your buoys will be, and the more effective your search will be.

[LuftWolf]

Conditions show a mud bottom, "bottom limited sound propagation", depths around 10k feet.

The performances you listed are pretty much what we intend for such acoustic conditions.

Thanks for the cover SQ.

Also, keep in the mind the layer will have a significant effect on sonar performance now, whether the sensor is on the same or opposite side of the layer, and whether they are in the surface duct or under the layer.

[LuftWolf]

I should also add to that other acoustic factors have a big part now in detection ranges, so now ranges are nearly situation specific to a large degree. Mission designers now have meaningful choices to make about acoustic conditions: SSP, bottom type, mean water depth, region, mean water temperature, time of day, sea state, and season, and cloud cover, to name a few.

Some factors play a bigger role than others in determining sound propagation for any given environment and how shadow zones in particular will form, but mission designers can now customize the acoustic environment to fit the overall theme and tone of their scenarios as they wish.

Think of it as that necessary ambience for a good party.

[swimsalot]

In terms of mission function, it would seem that a P3 laying bouys at a 500 yard spacing would be rather useless.
At that spacing, it would take 4 bouys to cover 1 mile.
So I dump 2 lines of bouys on a 3 mile stretch, that's 24 bouys.
With a typical loadout there's not much left.

If a P3 is screening ahead of a TF, that's not much real estate...
And if the Akula at 12 knots is that quiet, what about a KILO at 3?
Or a SW at 4knts?
Is this the intended result of the LWAMI mods, to make the range of a sonobouy less than 500 yards for a sub at 12 knots? Keep in mind, the bouys were at all different layers, deep and shallow. None got a contact before 700 yards, and that was only the VLAD for a brief moment without anything to actually get a bearing on.
Since a bouy dropped from even 250 feet at 154 knots is gonna drift some, it's rather difficult to place a bouy within a 500 yard accuracy, which is what would be needed here. If the ctc is more than 500 yards from the bouy it won't even turn hot; with the size of most maps, that rather limits the usefulness of a P3.
I'm certainly not questioning the work you guys have done, it's great. I just want to make sure I understand the ranges involved.

Just curious if I'm seeing this correctly, thanks for the help guys.
Swims

[OneShot]

@Swimsalot : Keep in mind this behaviour seriously depends on the conditions. And its the same in the unmodded DW as well. I played the Akula training mission (by Beer) in DW 1.0, 1.01 and 1.03 (without Mods) and its always a bitch because of the conditions in the ops area.On the other hand I had missions (with and without mods) where the Sonar conditions have been most favourable and I could get hits on subs over a couple of miles distance.

On your example with the CVBG. Keep in mind the P-3 seldom if at all works totally alone. In a CVBG for example it has the help from the forward deployed submarine and the escorts of the CV. On other missions it might be SOSUS or other means of detection.

Now speaking on behalf of the modders, the mod has actually improved the usefulness of the buoy load and extended the capabilities.

[LuftWolf]

Those same buoys and subs at the same speed in a Surface Duct would get detections at perhaps up to 2.5 nm or greater depending on the other conditions.

1.03 allows mission designers a very wide flexibility in setting acoustic conditions.

[Angle]

Originally Posted by swimsalot

In terms of mission function, it would seem that a P3 laying bouys at a 500 yard spacing would be rather useless.
At that spacing, it would take 4 bouys to cover 1 mile.
So I dump 2 lines of bouys on a 3 mile stretch, that's 24 bouys.
With a typical loadout there's not much left.

If a P3 is screening ahead of a TF, that's not much real estate...
And if the Akula at 12 knots is that quiet, what about a KILO at 3?
Or a SW at 4knts?
Is this the intended result of the LWAMI mods, to make the range of a sonobouy less than 500 yards for a sub at 12 knots? Keep in mind, the bouys were at all different layers, deep and shallow. None got a contact before 700 yards, and that was only the VLAD for a brief moment without anything to actually get a bearing on.
Since a bouy dropped from even 250 feet at 154 knots is gonna drift some, it's rather difficult to place a bouy within a 500 yard accuracy, which is what would be needed here. If the ctc is more than 500 yards from the bouy it won't even turn hot; with the size of most maps, that rather limits the usefulness of a P3.
I'm certainly not questioning the work you guys have done, it's great. I just want to make sure I understand the ranges involved.

Just curious if I'm seeing this correctly, thanks for the help guys.
Swims

I feel ya swimsalot. The mission taipei strike for instance. They give you a LARGE search area. NO where to land and get more bouys. And you have to get those close even with the bouys and target are above the layer.

[SeaQueen]

Originally Posted by swimsalot

If a P3 is screening ahead of a TF, that's not much real estate...
And if the Akula at 12 knots is that quiet, what about a KILO at 3?
Or a SW at 4knts?

You're right.

What you're seeing here is actually echoing a real life debate - how close into shore do you want to bring your warships?

One of the reasons real life COs do not like to go in close to land is that the bad acoustic conditions in the shallows limits their ability to defend themselves from submarines quite severely. It's safer out in the deep where you can expect a convergence zone, maybe more than one. ASW in bottom limited, shallow water is one of the most difficult things one can do.

I think it's interesting that nobody has talked about dropping active buoys. If you can't count on passive detection, start banging away with your active.

There are other things you can do, too. If the task force moves quickly enough, then the P-3 doesn't need to cover as much because the kinematics of the situation insures that the space in which possible submarines might be located and still come within firing range is smaller. Surface ships have the advantage of speed over submarines.

Even then, maybe you just won't be able to cover the area and insure a probability of detection of more than like 0.5, say. If that's the case then maybe you've created a contrived scenario where they wouldn't ever bring a large task force into that area. They'd instead leave it for "expendable" surface combattants. There's lots of different possibilities.

[Angle]

Getting a return with an active bouy is easy enough. But in some instances you need to classify the contact. That means getting a bouy really close.

[TLAM Strike]

Originally Posted by Angle

Getting a return with an active bouy is easy enough. But in some instances you need to classify the contact. That means getting a bouy really close.

Or you just go for a MAD run and see if you get a SAD return, or any return for that matter.

[Angle]

Getting a SAD return might not be enough. What if there are friendlys in the area.

[TLAM Strike]

They should have reported their position. Sometimes a 50 hrz tonal and a SAD return are all you have to go on.

[Angle]

Lol TLAM. Been in many friendly fire incidents? heh. Depending on the mission and rules of engagement. Some of the allies might not be link participants.

[TLAM Strike]

Originally Posted by Angle

Lol TLAM. Been in many friendly fire incidents? heh.

Only one, and it wasn't my falt.