Submarine Tactics

[Nautilus]

I thought I kick off a discussion on submarine operation and tactics in general. I hope this is the right forum and the title is sufficiently close.

Russian and Chinese subs are often described as nosier than their western counterparts. The way I understand it, SSK's generate quite a bit of noise when running on diesel engine but comparatively little noise when running on batteries. Since there are no cooling pumps (?) that have to run permanently like on SSN's, I assume SSK's can be totally silent while holding a position right?

So would it be save to say, that SSK's generate noise proportionally to the speed they are traveling at (on batteries that is)?

 

[Francois]

I thought I kick off a discussion on submarine operation and tactics in general. I hope this is the right forum and the title is sufficiently close.

Russian and Chinese subs are often described as nosier than their western counterparts. The way I understand it, SSK's generate quite a bit of noise when running on diesel engine but comparatively little noise when running on batteries. Since there are no cooling pumps (?) that have to run permanently like on SSN's, I assume SSK's can be totally silent while holding a position right?

So would it be save to say, that SSK's generate noise proportionally to the speed they are traveling at (on batteries that is)?

First, you have to understand that to propel a sub, whatever the power plant, you have to make noise. All the work is on reducing this noise.
SSks, when running on batteries, are quite silent. But a nuke at slow speed usually (at least on all western designs) does'nt need too use its pumps. The circulation is done naturally. So it can be very quiet too.

The SSK have to compromise between, while running on batteries, speed and time. As the comsumption (Amps per hour) draw the batteries out the more you pump on it.

And finally, if I understood your question, a submarine staying on the ground with all systems off is just quiet. No noise emitted. Just a sitting hull.

 

[gf0012-aust]

a submarine staying on the ground with all systems off is just quiet. No noise emitted. Just a sitting hull.

a sitting hull is still detectable (depending on which country is doing the searching and hunting)

acoustic transmission is just one element of sub detection - I suspect that Francois is giving you a sanitised overview..

 

[Francois]

a sitting hull is still detectable (depending on which country is doing the searching and hunting)

acoustic transmission is just one element of sub detection.

Yes, Gary, you are right, a hull can be detected even without moving, but the hunter has to go active... And it is rather not good.
And I know few ways to avoid to be detected this way also... or just confuse the hunter!

 

[gf0012-aust]

Yes, Gary, you are right, a hull can be detected even without moving, but the hunter has to go active... And it is rather not good.
And I know few ways to avoid to be detected this way also... or just confuse the hunter!

Generally speaking you're right, but again, depending on which country we are talking about, there are ways to find a sleeper without going active.

There are 4-5 countries that have alternative passive detection systems capable of finding "sea bed sleepers"

 

[Nautilus]

Ok... so would it be save to assume that a (well maintained) Kilo class sub can achieve the same level level of silency at a lower speed compared to a modern western SSK?

Also... I've been reading some other threads here over the last couple of days and I believe somewhere it was mentioned that a larger sub is harder to detect than a smaller one? This would have to be in regards to passive sensors as a large sub has more surface area for a active sonar to detect. I still don't quite understand the principle of this?!

 

[gf0012-aust]

Ok... so would it be save to assume that a (well maintained) Kilo class sub can achieve the same level level of silency at a lower speed compared to a modern western SSK?

In my experience - no. The latest Kilos that India has just received still has lousy old generation propellers. IMV, they've compromised capability by not spending a fraction more money. bad penny pinching

Also... I've been reading some other threads here over the last couple of days and I believe somewhere it was mentioned that a larger sub is harder to detect than a smaller one? This would have to be in regards to passive sensors as a large sub has more surface area for a active sonar to detect. I still don't quite understand the principle of this?!

A sub is a transducer, at an acoustic level, the bigger it is, the easier it is to manage noise and vibration. It's a contradiction of the physical low observability principles that would apply to surface vessels, or combat aircraft. The medium is different, hence NV issues and detection methods are almost opposite.

Larger subs like the Collins Class also have the appropriate mass to include fixed flank arrays - that means that they are incredibly capable of long range broad detection - far more so than 95-99% (IMO) of all other existing subs.

Smaller subs are designed for different roles, they are not fleet assests, fundamentally they are coastal and/or littoral assets. each role has advantages and disadvantages according to the owning navies doctrine.

 

[Nautilus]

Was this the motivation to build the Collins class larger or does more have to do with the need for range given that Australia in on the Pacific?

How useful are larger SSK's in littoral areas? Are the at risk to run aground? Sorry if these questions seem silly...

Can anyone recommend a good book on submarines (and other warships)? I've been looking at "Combat Fleets.." but the price is just a tad steep

 

[gf0012-aust]

Was this the motivation to build the Collins class larger or does more have to do with the need for range given that Australia in on the Pacific?

Aust is responsible for 1/9th of the worlds major oceans/waterways - so we have a large backyard to manage. Bear in mind that these were designed at the arse end of the cold war, so there was a vision of using them as "fleet assist" units as well as lone rangers. They have very high tempo rates (days available on station) so add the numbers up and you can start to work out what they were designed to do.

How useful are larger SSK's in littoral areas?

Very useful, plus add in the fact that apart from new detection systems being available, they're also going to be armed with the Mk48 Blk 70, designed specifically for the littorals.

Are the at risk to run aground?

any poor bugger can run aground, look at the poor pom who hit the only big rock off of WA. Stuff happens.

Can anyone recommend a good book on submarines (and other warships)? I've been looking at "Combat Fleets.." but the price is just a tad steep

Bakers is actually one of my favourites, but you can pick up Janes Naval etc for less than $90 USD if you're prepared to get a version thats 5 years old.
I personally prefer Bakers over Janes, but they both have pluses and minuses I guess

 

[Francois]

Gary, I was trying to comply to the internet-mean-knowledge, and not to give tricks away.
Big subs also have the advantage that, as any ship, the bigger the fatsrer. It is a naval rule since boats are sailing the seas. Plus, you have more room for silencing devices.

I remenber that Waller sunk few boats in Rimpac 2000 in 70m waters.
That is not deep (shallow) near Hawaii.

 

[gf0012-aust]

Gary, I was trying to comply to the internet-mean-knowledge, and not to give tricks away.
Big subs also have the advantage that, as any ship, the bigger the fatsrer. It is a naval rule since boats are sailing the seas. Plus, you have more room for silencing devices.

I remenber that Waller sunk few boats in Rimpac 2000 in 70m waters.
That is not deep (shallow) near Hawaii.

I missed the subtlety of your message..

IIRC Sheehan evaded a concentrated attack by a dedicated DTF and a flight of Orions ex Guam, and she was within the 12 mile limit in a test area - that close to shore is not normal and can be decidedly uncomfortable for the pursued...

They still didn't find them

 

[Nautilus]

How much of a difference do thermal layers make under water? If a sub went to 200-300m depth, would it significantly harder to detect it than say at 30m from the same distance?

 

[Nautilus]

Bakers is actually one of my favourites, but you can pick up Janes Naval etc for less than $90 USD if you're prepared to get a version thats 5 years old.
I personally prefer Bakers over Janes, but they both have pluses and minuses I guess

Good to know that it is a good book but still a bit too expensive for my taste. I can't write it off as a business expense

What other books are worthwile (lets say in the price range under $100)? I am particularly interested in submarines, sub warfare and tactics but also in warship design in general. Recommendations highly appreciated

 

[gf0012-aust]

How much of a difference do thermal layers make under water? If a sub went to 200-300m depth, would it significantly harder to detect it than say at 30m from the same distance?

30m is more or less a death wish under combat conditions. anything in the sky with a beedy eye would have a good chance of seeing you - unless the water you were in was a variation of the Yarra - then you'd never be found.

 

[Pendekar]

the rule is, the deeper the sub go, the safer it is. higher pressure deep underwater will prevent cavitation noise and that mean the sub can travel at fairly high speed with minimal risk of detection, plus better sonar performance.

i've read somewhere that Russian kilos was called a "black hole" by NATO personals for it's capability to "disappear".

Generally speaking you're right, but again, depending on which country we are talking about, there are ways to find a sleeper without going active.

There are 4-5 countries that have alternative passive detection systems capable of finding "sea bed sleepers"

how is it done? can u be more specific? i heard about the blue Laser onboard the RORSAT that was suppose to penetrate deep underwater. is this what u mean? or maybe a MAD type sensor? or maybe a new USN active sonar system that cause some environmental fiasco few years ago and claimed to be able to detect a sub 300 miles away?

i'm well aware of how a broadband sonar search work, but i'm not quite understand about narrowband. how was it searching for dicreet frequencies fare any better then searching in wide spectrum?

 

[gf0012-aust]

the rule is, the deeper the sub go, the safer it is.

Not true

higher pressure deep underwater will prevent cavitation noise and that mean the sub can travel at fairly high speed with minimal risk of detection, plus better sonar performance.

Not true

i've read somewhere that Russian kilos was called a "black hole" by NATO personals for it's capability to "disappear".

It was in reference to a quantum leap that the russians made in noise management of their prev generation of subs. It was relatively true then (thanks mainly to Toshiba) , it is certainly not as true now. There are any number of subs that are quieter than a Russiam Kilo (export Kilos are a different beast altogether)

how is it done? can u be more specific? i heard about the blue Laser onboard the RORSAT that was suppose to penetrate deep underwater. is this what u mean? or maybe a MAD type sensor? or maybe a new USN active sonar system that cause some environmental fiasco few years ago and claimed to be able to detect a sub 300 miles away?

There is nothing in the public domain about current systems.

i'm well aware of how a broadband sonar search work, but i'm not quite understand about narrowband. how was it searching for dicreet frequencies fare any better then searching in wide spectrum?

I didn't say broadband, I referred to a flank array system allowing broader capability.

 

[Francois]

Nautilus, there are loads of books talking about tactics and sub history.
I will recommend you to search in Amazon.com and read the comments from readers.

Pendekar, the dynamics of sound propagation in the water is nothing like a given simple equation.
You can, at the same time, not hear a contact at few yards from you (see Ehime maru tragedy), and get a contact at 1000 nm.

Deeper doesn't mean safer either. And thermal layer never lay at the same depth. Sometime you can have several layers, and sometime none.
The submarine has to study its environment in a hourly basis. Nothing is given herebelow.

You see, Gary, you made raise eyebrows and questions...

Blue lasers in Rorsat is still sci-fi too. Sounds like DiMercurio hehehe!!

 

[gf0012-aust]

Pendekar, the dynamics of sound propagation in the water is nothing like a given simple equation.
You can, at the same time, not hear a contact at few yards from you (see Ehime maru tragedy), and get a contact at 1000 nm.

Agree, you can record a sounding charge going off at literally 3000 miles, but then not hear a fish fart 150ft away. Water is an odd medium with lots of variables.

You see, Gary, you made raise eyebrows and questions...

oh well, at least web is smiling as he'd getting more site hits!

Blue lasers in Rorsat is still sci-fi too. Sounds like DiMercurio hehehe!!

it's bad enough trying to generate approp length for the new generation DVD's - let alone send them 90,000m miles through space and then penetrate water at maximum interrogative depth.

 

[Francois]

i've read somewhere that Russian kilos was called a "black hole" by NATO personals for it's capability to "disappear".

Pekendar, I have never seen any NATO document stating that.
This is pure fiction (i.e. Patrick Robinson), and Kilos are not the quietest subs around, from far.
Though the Pr636 have been improved in this area (redesign of the propelled, added accoustic devices, and all), but they kept the same motors then 877s. And these motors were already too weak and not flexible at the time.
Plus, the redesign of the propellers have them quieter, but the gain is lower.

Less power egal less flexibility.
471s and O-class have the best weight/power ratio in the world ! (for SSKs of course).:coffee

 

[Nautilus]

Yeah... in fact I went to Amazon last night and ordered a number of books. Looking forward to reading them soon.

I read that the Kilo's are equipped with AA missiles, presumably to shoot down choppers searching. Seems like an interesting capability - how come no such system is used on western subs?

Doesn't the effiiciency of a sub largely depend on its crew? How do countries like Russia, China, Iran, India and Pakistan stack up in terms of training of their submarine force?