That my friend is a thing that I agree with you. The 688 should not be able to detect a well handled SSKs so easily. Try RA.
But of course everybody has got their own estimates on how far out a well handled SSK could begin to be detected. . .

In that regard, the RA has a substantially much lower estimates than the LWAMI and stock.


But to defend LWAMI estimates or RA estimates we need hard data which is of course not available to public so this point is not worth debating over. Just throw your opinion and let it be because there is now way to truly defend it. Neither LWAMI or RA estimates.

Only people with RL experience aboard the Kilo or US Los Angeles class have any clue to what we have been discussing here and they are not going to speak up for sure because of their oath of secrecy. So unless you claim to have served aboard a Los Angeles class submarine that had detected a Kilo or aboard a Kilo that had detected a Los Angeles class submarine it is pointless to debate this over.

It was not that you are more noisy, it is that you lose sensor sensitivity. You did not want to blunder into someone because you could not hear them. If you got too close you give them a chance to hear you.

Both reasons that you and Frame put are reasonable imo. So both are probable.

Even with certain mods installed, I find the Kilo Improved shows up on the waterfall from quite a distance, at least 5nmi, even when they are stationary or drifting at 1 Kt. Is that realistic? What's making the noise? Sea floor was ~300ft.

PS - It's the sphere usually that grabs the signal, but the TA also picks it up somewhat less well and usually without good tonals.

Pillar I belive you must be using AT not RA installed. AT is LWAMI with more playables and new 3D models.

In RA I don't think you can detect diesel sub passively unless you're very very lucky and that advantage is already lost once you realized that you've detected a diesel.

Humm that doesn't sound correct, I did a test long ago and a Kilo stopped and lying in the seabed was not heard by a Los Angeles even if at a few hundreds of yards :hmm: As it should be, BTW, because a stopped diesel-electric theoretically does not generate any noise.

If electric subs were this amazing, why hasn't the US, France, the UK, Russia, invested in diesel electric or AIP subs as their front line SSes (as opposed to SSNs). Clearly if you can't be detected at all that makes up for any transit time problems. The reason they haven't is because: Diesel-electric subs are marginally quieter than nukes, even at low speed, they are slower, incapable of acting as much more than a smart mobile mine, and limited in range and engagement ability. There is one big advantage of non-nuclear propuslion, its cheap.

That's not the only reason. The US is a nation that projects its force far away, they want to be able to wage war far from their frontiers -that has worked well in the past- and a diesel is obviously too short ranged and dependant from supply to do that.

We are talking here about the Kilos, but think about the modern european projects, the U-214 is a marvel, much quieter than a nuke, with huge firepower and good solutions for Germany and many nations that don't need anything else than coastal defence.

Passive sonar ain't the only sonar...

Reinstalled fresh, patched 1.04, installed a mod (Not AT or LWAMI).. result: Kilo on waterfall ~8nm, Kilo doing 1kt straight towards me. My platform was SSN Seawolf.

I can't figure out how to get the Kilo to sit at 0 knots.

Anyone want to send me a test scenario that they have working on their end? m o i ety12 at hotmail, add the com ignore the spaces.

Also state sea state, bottom type and SSP type.
Bottom type affects signal strength (rock best, mud worst), sea state affects noise.
For these test I suggest bottom limited SSP.

Russia is building an AIP sub for itself IIRC - the Saint Petersburg. It just isn't building anything very fast due to budget issues. The UK also wanted diesels until it was diesels or nukes.

As for the US, there is this phobia that if they make workable diesels, that's all they will get in the future, especially if the costs of subs skyrockets like they do...

It will not have any propulsive noise, however that does not mean it is silent.

Unless they are using direct DC powered gear (and that would be difficult), you are going to have the DC-AC Motor generators running that are providing power to the AC buses. You will have HVAC equipment running in order to maintain the proper temp in the boat. You will also have other ancillery gear running that is required to operate and fight with the boat and maintain habitability. All it takes is ONE piece of equipment to soundshort and you are royally screwed. That is where the 50/60hz tonals come from. The AC bus and the equipment that it runs.

It is these CONSTANT equipment noises that will give you away. Yes, you can raft and sound isolate most of this gear, but you have to remember: a diesel boat is SMALL and that limits what you can do. The more mass that a electric powertrain has to move, the shorter its legs. Thus they will scrimp and cut corners in that all important weight/effectiveness consideration. You also have to bring on FUEL. This is a LOT of mass that has to be considered into this equation. Thus as you can see there are a LOT more variables here than I think you realize. I could give some good real world examples and such, but I hope the point has been made.

With a nuke boat you have unlimited fuel. You do not have to worry about your underwater endurance. You can include the more comprehensive rafting and sound isolation considerations. You are not worried about the size of your boat because you have a LOT more power that will not run out on you. You then have OTHER considerations but the biggest one is solved and manageable.

A diesel boat is quiet. But it is not as quiet as you would believe.

Also, there is something BAD about being DEAD quiet. If you can isolate a line of bearing that is LOWER than background noise and is MOVING. Um.. guess what, you have found something that is trying to hide. That was becoming a problem when I got out. The sonar gear was getting so good you could do just this and they actually had to make sure that you did not get TOO quiet as a large moving object that is occluding background noise and moving at 8 knots can be a bad thing.

Hehe, wow.

I changed the test from rocky to sand and surface duct to bottom limited... now I pick up a 1kt kilo from about 2.5nm on the sphere. Better, but still... that's a long way!

I'd love to hear more about equipment noises BN. Those real world examples you alluded to would be welcome. Interesting stuff.

Can't a Kilo just shut down everything and go dead in the water if it wants to? You'd only need to do it for a short time, to let the baddies pass by. I guess I'd really like to see the diesel electric boats be able to just disappear entirely from passive sonar when they hit zero knots.

The US Navy uses nuke boats because they are FAST and have essentially unlimited endurance. They are supposed to take the war to the OTHER guy in short order. They also have to provide ASW defense for a surface action force. They will sprint ahead and sanitize an area that they are going to pass through. This means they need high speed and endurance.

With intel/spec ops, it is the ability to loiter for long periods of time without having anything other than a mast or 2 above the surface. You do not have to charge batteries. You do not have to LEAVE the area TO charge the batteries. You can sit right on someone doorstep and listen/watch and they will never know you are there. In the event you are counterdetected, you can clear datum QUICKLY, evade the search, and them come right back.

In wartime, it is not area denial that the USN is interested in. As someone said earlier, a diesel boat is effectively a smart minefield. Yes, it is mobile, but there are severe restrictions that are applied to it. The latest generation of AIP is changing this some, but it moves it from a local to a regional area. It does not make it GLOBAL.

Yes they are more expensive, but they have a MUCH broader mission that you can possibly know unless you served on one.

The tonals I pick up are 1050 and 1500 roughly, and on the sphere. The TA doesn't hear a much of anything with "sand" and "bottom limited"...

What equipment do those tones represent? What am I hearing?

Nope, not really. Sounds good on paper but in reality you do NOT turn off vital gear (sonar & fire control systems, steering and diving hydraulics, DC-AC converters, atmopshere control, etc etc etc) unless you REALLY REALLY have to. It might not come back on. :o

As I said, there is a LOT more going on here than you might think. EVERY submarine has what we called 'hotel' loads. These are things that NEVER get turned off (unless for maintenance and then under VERY controlled conditions). They are what we termed 'vital'. Some of these items REQUIRE you to return to port if they went down as the safety of the boat could be jeopardized. Granted, in wartime we had diffrent rules, but I hope that lends the level of importance of these systems.

Yeah I see what you mean. I'm curious what specifically might be giving out those tones.

Boats have either 50hz electrical gear or 60hz electric gear. This is just like the AC that is in your house. North American and some other places use electricity that is running at 60hz. Russia, Europe and others run at 50hz. There are different voltages as well, but they do not matter for this discussion.

For the MOST part, you end up using the same frequency on your sub that you use at home. That is so you can sync up to shore power (hey, you didn't think we run the plant ALL the time did you) and power the boat from regular electricity.

When you get a freqency on sonar, you are picking up a piece of equipment. Sometimes what you are hearing is a harmonic of the base frequency of this equipment. This can be usefull in telling you what nationality the contact may be. If you are getting harmonics of a 50hz then you can pretty much rule out an american contact. (sonar guys, can you lend a hand here? It has been awile since I had to think of this part of the boat. Quals were a LONG time ago)

Now, as to what may be MAKING that noise?? Well, that is classified WAY up there. Each contact class has its OWN set of distinct tonals. If you get a good enough cut on the contact, you can tell WHO and WHAT it is. You can tell this down to a specific ship I believe.

One of my assigned duties was Sound Silencing. I had to make sound cuts of EVERY STINKIN PIECE of mechanical gear on the boat and work to minimize this problem. Let me tell you, that job took a LOT of patience and had a lot of stress. Think about it. I was responsible DIRECTLY for the overall quietness of the equipment and thus the BOAT. If I messed up, my shipmates lives were at stake.

Want to know pride? I was on a 3rd flight VLS boat and we took out a 688i in a TOPTORP competition. On paper, there were supposed to be WAY quieter than us. We flat creamed them. I got an admirals letter of commodation for the work I did. The hard work paid off.

Speaking of diesel lately I've been reading 'submarines in Indonesia' in which it in part tells about the whiskey class diesel sub.

In every domestic (up to a period I assume) naval ASW exercise the whiskey and the newer type 209 of the Indonesian Navy for that matter have never been able to be detected by surface combat forces. These diesel subs were very very quiet.
The results of these exercises were photographs of the surface combatant hulls.

One Whiskey even came close to a British carrier passing near Indonesian waters during the 60s I think. It surfaced when it was well within torpedo range after taking photographs of the carrier to say Bon Voyage! :D