Littoral advantages

[NFunky]

Well nobody anwered my other post, but I think this one might be a little more interesting to the community. It's a question again and one I've wondered about for a while.

What exactly are the advantages a diesel sub has in littoral waters, especially against surface ships? The only one I can think of is that it is more difficult, if not impossible, to use a towed array. In real life, medium-to-low frequency active sonars are more likely to blank out their own recievers, but this doesn't really seem to be the case in DW. With no layer, there is no way to move into the sonic shadow area and thus practically avoid active detection. Helos and ASW aircraft are just about as effective as they would be in deep water too, especially since I am forced to be closer to the surface and thus more vulnerable to MAD detection.

So really, why does everything I've read say that ASW is more difficult in littoral environments, particularly against non-nuclear subs?

[MarkShot]

The littoral:

(1) Greater amount of surface traffic.

(2) More surface noise from surf action and bottom affect on acoustics.

(3) Nukes continuously cool their power plants and run turbines. When elec sub is not moving or barely moving, there is hardly anything moving which makes noise (ready batteries make no noise).

[NFunky]

All very true in real life, but how much is modeled in DW? I know from testing that unless the sea state is very high and/or the bottom type is sand or mud, sonar tends not to be degraded very much in littoral areas. Your point about surface traffic hadn't occured to me, but that's generally up to the mission desiger and only assists slightly as far as sonar evasion.

I remembered another advantage though. In certain green water environments, it's possible to make use of underwater hills and such concealment, but most of the time the sea bottom slope is to gradual to be of any use.

[SeaQueen]

Originally Posted by NFunky

What exactly are the advantages a diesel sub has in littoral waters, especially against surface ships?

The answer, in part, depends on what you mean by "littoral" and also which diesel electric submarine you're up against. Not all diesels are created equal.

The DW sonar model does include bottom interactions in the sense that in shallower water (about 9 thousand feet or less) the bottom type can matter a lot. It doesn't include some of the frequency dependent aspects of sonar performance such as cutoff frequencies and what not, which might mean a lot to a submarine. For example, very shallow water (hundreds of feet) makes it harder to detect a submarine using narrowband processing because lower frequency tonals are not going to be propagated very well. Unfortunately, the lack of frequency dependent behavior is a symptom of DW having some sort of ray tracer as it's sonar model.

With no layer, there is no way to move into the sonic shadow area and thus practically avoid active detection.

There are other ways to avoid detection. The most important of which is just to keep your distance from surface warships banging away with their active sonar. In shallow water, DW surface warships typically detect a Kilo at 2-3 miles. Since a wakehoming torpedo has a range of 10 miles, 2-3 miles of detection range doesn't buy you very much.

Helos and ASW aircraft are just about as effective as they would be in deep water too, especially since I am forced to be closer to the surface and thus more vulnerable to MAD detection.

This point is more complicated than you're making it out to be. In my mind, it could mean lots of things. In real life, since acoustic sensors are less reliable, it's not unreasonable to expect that non-acoustics would be your most effective sensors. In this sense, it's not an unrealistic tactic in shallow water to expect first detection to come from MAD, radar or even visual sensors. The game reflects that in a sense and more than once in shallow water scenarios, I've made first detection with MAD other non-acoustics. In shallow water non-acoustics are not to be discounted.

MAD however, continues to be short-ranged in DW so it's difficult to really use as a search sensor against a target that hasn't already been somewhat localized by other sensors. If people are using MAD as a search sensor with high likelyhoods of detecting their targets, it's probably because the target's location is constrained to a small area. You don't need a bright flashlight to search for something in a shoebox successfully. It's when you've got the whole basement to look through that it's a problem. I've noticed this problem in many DW scenarios, where people designed it to be fast-moving rather than realistic so everyone begins basically already localized. I've seen some where statistically you could fire a torpedo at spawn without even detecting anyone and expect it to hit someone without having to even think about it.

So really, why does everything I've read say that ASW is more difficult in littoral environments, particularly against non-nuclear subs?

It depends. Sometimes, it's actually not any more difficult than against nuclear submarines. If there's a good surface duct you might even do better than against a nuke because surface vessels can count on increased active sonar performance and diesels tend to stay shallower than nukes because they have to snorkel. Some if it is that DW doesn't capture everything there is to be captured in how sonar behaves. Some of it might also be poor scenario designs, and some of it might also be the databases not reflecting the actual performance of some submarine designs for various reasons. Some of it is that the environment's variability is not very well captured either. The effects of fronts and eddies, for example, can have a profound impact on some types of sonar performance. Anyhow... there's a lot of stuff.

[Dr.Sid]

To SeaQueen: DW uses no raytracer. It's much much simpler. Check my measurements
http://www.subsim.com/radioroom/showthread.php?t=117814
I have still found no effect simulated beyond what's in the thread.

In DW main advantage of Kilo in literal waters is that Kilo is smaller and turns better. Try 'Kilo Demo' mission with Seawolf.