Submarines Noise levels

Diesel Submarine Radiated Noise Trend

Actually I have a bit of trouble believing that chart Austin, first of all those American stars are nukes and not diesel electrics.

Second is it showing diesels operating with diesel engines running or on electric drive... quite different things BTW.

When running off batteries most diesel electrics would compare quite favourably to most nukes as there are no noisy gears or reactor cooling pumps operating.

Equally even a noisy sub can be operated near a choke point in a lie and wait tactic where it can remain noiseless and motionless waiting and listening for targets to come past it.

^^ Garry , Dont take that chart as a gospel truth but a trend in conventional submarine.

Its true that Nuclear Submarine have lot of pumps ,reactor running which would make them noisy , compared to conventional subs running on battery.

But Nuclear submarine have far more comprehensive silencing measures implemented in them , the much bigger size and unlimited power allows them to do so . While Diesel Electric Submarine have their limitation on size and power hence they are limited to what can be implemented to reduce acoustic field.

There is some thing called Full Silence regime on Nuclear Submarine where it moves at slow speed ,all non essential stuff including pumps are shutoff , moments are restricted ( even no toilets ) , so Nuclear sub can remain and be more silent then diesel subs.

Choke point business are best done by Conventional Subs , they are small in size ,choke point depth ( generally not greater then 200 m ) allows them to lie low and run on battery for long without the need to recharge for long time and AIP makes it much longer.

Its always good to have a mix of Nuclear and Conventional subs as they have their own task cut out and are good at specific task , In US there are lobbies that think opting for Conventional Subs will eventually kill Nuclear submarine and their associated industry

Thankfully Russia did a right thing of having mix of both , its a cost effective option as well.

My main problem with the chart is that it doesn't actually list the scale of noise, it just says it is in decibels.
As such the scattering of subs on the chart mean little except the downward slope suggests they are all getting quieter... which is a given anyway.

Its true that Nuclear Submarine have lot of pumps ,reactor running which would make them noisy , compared to conventional subs running on battery.

There are reactors that use natural circulation for cooling, but at the end of the day lots of noises on subs like opening torpedo doors, pumping water into and out of ballast tanks for trim, propeller noise, mechanical noise is going to be less on an electric than on any other type. Non nukes have their advantages especially in shallow waters because of their smaller size and manoeuvre capability and of course cost, but their fundamental advantage is in their reduced noise signature because electric motors make very little noise even at full power.

But Nuclear submarine have far more comprehensive silencing measures implemented in them , the much bigger size and unlimited power allows them to do so .

If that were true then the US could simply test its anti sub capability against its own nuclear power subs instead of inviting European and Australian conventional subs to exercise with them so they can practise operating against conventional subs.
It seems these tests were useful and the USN has invited a European country to keep sending its subs for exercises.
What would be the point if diesel electrics were noisier than nukes?

There is some thing called Full Silence regime on Nuclear Submarine where it moves at slow speed ,all non essential stuff including pumps are shutoff , moments are restricted ( even no toilets ) , so Nuclear sub can remain and be more silent then diesel subs.

Yes, I know about running silent on a sub, but even running on silent in a nuke and a diesel electric are not the same thing... in a nuke you keep the reactor running which means noise. In a diesel electric that means running on electric which is much quieter clearly... even in a natural circulation reactor there is the noise of fluids moving that doesn't sound like other things in the ocean.

In US there are lobbies that think opting for Conventional Subs will eventually kill Nuclear submarine and their associated industry

There are lobbies in the US that think universal healthcare is communism too.

A kilo could probably operate for 4-5 days on batteries before having to recharge... that is plenty of time to sit and wait for the right target or lay mines and sneak away to recharge.

GarryB wrote:My main problem with the chart is that it doesn't actually list the scale of noise, it just says it is in decibels.
As such the scattering of subs on the chart mean little except the downward slope suggests they are all getting quieter... which is a given anyway.

These are just trends and not a ballpark figure ,even if scale were to be provided it would be little value.

I find it hard to believe to believe that Australian Collins are being rated in noise equal to advanced Kilo when they were mentioned as Rock Band under water by Western media and German U-212 being rated lower then adv Kilo when it should be on par or better.

There are reactors that use natural circulation for cooling, but at the end of the day lots of noises on subs like opening torpedo doors, pumping water into and out of ballast tanks for trim, propeller noise, mechanical noise is going to be less on an electric than on any other type. Non nukes have their advantages especially in shallow waters because of their smaller size and manoeuvre capability and of course cost, but their fundamental advantage is in their reduced noise signature because electric motors make very little noise even at full power.

Yes I am aware of the use of natural circulation at slow speed but those noises from ballast , motors , trip etc affect conventional and nuclear subs and a nuclear subs have much bigger sonars and other sensors to catch up such noises compared to conventional subs.

Conventional subs are good for choke and intelligence gathering operations.

If that were true then the US could simply test its anti sub capability against its own nuclear power subs instead of inviting European and Australian conventional subs to exercise with them so they can practise operating against conventional subs.
It seems these tests were useful and the USN has invited a European country to keep sending its subs for exercises.

They do lot of test viz a viz conventional subs against Australian or European countries , these are tactics , weapons ,how to play ball in shallow waters and even open seas , lot of stuff besides noise , A sub is more then just noise.

What would be the point if diesel electrics were noisier than nukes?

because its cheaper to build and operate ,very few countries can build and operate quality nuke subs and with AIP the conventional subs are getting better and as I said submarine is more then noise , Tactics , Weapons ,Training and Doctrine play an equal role.

Yes, I know about running silent on a sub, but even running on silent in a nuke and a diesel electric are not the same thing... in a nuke you keep the reactor running which means noise. In a diesel electric that means running on electric which is much quieter clearly... even in a natural circulation reactor there is the noise of fluids moving that doesn't sound like other things in the ocean.

Nuke Subs do have battery on them to provide powers and they have small creeper propellers one can see in Akula that gives them slow speed.

All things being equal which I have mentioned above a 4th gen Conventional Sub like Lada will have its own advantage over 4th gen Yasen in shallow water operation.

So conventional subs do have an edge in specific roles.

There are lobbies in the US that think universal healthcare is communism too.

I think that was also a reason Democrat got defeated in recent Senate elections , health care is good as long as it can profit the big companies out there.

A kilo could probably operate for 4-5 days on batteries before having to recharge... that is plenty of time to sit and wait for the right target or lay mines and sneak away to recharge.

The Kilos are quite potent subs and can do many different task and these days they even come with Klub.

http://manglermuldoon.blogspot.in/2013/12/chinas-anti-access-strategy-submarine.html

To provide a point of reference, the following acoustic signatures are from "Chinese Evaluations of the U.S. Navy Submarine Force" and "CHINA’S FUTURE NUCLEAR SUBMARINE FORCE"

Ocean background noise - 90 decibels
Seawolf-class - 95 decibels
Virginia-class - 95 decibels
636 Kilo class - 105 decibels
Akula-class - 110 decibels
Type 093 - 110 decibels
Type 094 - 120 decibels

Even Russian sources put Akula at 110db , SL discrete frequencies in 5-200 Hz spectrum
(dB relative to 1 Pa at 1m)

http://www.armscontrol.ru/subs/snf/snf03221.htm

[quote="Austin
I think NATO employs intel vessel and its not unkown fact that SSN track or atleast try to track SSBN and russian captain says that so.[/quote]


Trying to track and keeping track are two different words .

[quote="Austin"]

http://manglermuldoon.blogspot.in/2013/12/chinas-anti-access-strategy-submarine.html

To provide a point of reference, the following acoustic signatures are from "Chinese Evaluations of the U.S. Navy Submarine Force" and "CHINA’S FUTURE NUCLEAR SUBMARINE FORCE"

Ocean background noise - 90 decibels
Seawolf-class - 95 decibels
Virginia-class - 95 decibels
636 Kilo class - 105 decibels
Akula-class - 110 decibels
Type 093 - 110 decibels
Type 094 - 120 decibels

what are his credentials ?

From blog

Matt : The views expressed on American Innovation are entirely my own and do not represent anyone else.

Austin wrote:http://manglermuldoon.blogspot.in/2013/12/chinas-anti-access-strategy-submarine.html

To provide a point of reference, the following acoustic signatures are from "Chinese Evaluations of the U.S. Navy Submarine Force" and "CHINA’S FUTURE NUCLEAR SUBMARINE FORCE"

Ocean background noise - 90 decibels
Seawolf-class - 95 decibels
Virginia-class - 95 decibels
636 Kilo class - 105 decibels
Akula-class - 110 decibels
Type 093 - 110 decibels
Type 094 - 120 decibels

Even Russian sources put Akula at 110db , SL discrete frequencies in 5-200 Hz spectrum
(dB relative to 1 Pa at 1m)

http://www.armscontrol.ru/subs/snf/snf03221.htm

Ocean background noise of 90 db has got to be some sort of a joke.    The normal background is under 70 db.
(www.usna.edu/Users/physics/ejtuchol/documents/SP411/Chapter11.pdf).

The claim that the 636 Kilo is 105 db vs 95 for a Virginia class is yet another example of BS spawned by some
sort of inadequacy syndrome.   This spam of numbers reminds me of the yapping about stealth.   Supposedly
the F-22 has the radar cross section of a pea.   The question is what radar frequency and what angle of incidence.  
Without answering these questions the claim is empty.    The same goes for these noise figures.   Apples and
oranges comparisons without any credibility.    When the 636 is running on batteries it is significantly quieter
than the larger Virginia *nuclear* submarine.

Akula's running on the low-speed propulsors would be quieter as well... Claims like these are baseless to say the very least. 

Akula-2 is said to be significantly quieter than the improved-LA, and as such it can't be far off from the Virginia. Don't forget that dB numbers are not "fluid" and the actual noise level varies dramatically over a small number of units. 

This list would put the Virginia at under 1/2 the loudness of an Akula, which is doubtful.

The Typhoon is actually a very quiet submarine... its enormous size means plenty of space for sound reduction measures... and of course being an SSBN it does not need to actually go anywhere at speed so it does not need to move at all greatly reducing the amount of noise it has to make.

To provide a point of reference, the following acoustic signatures are from "Chinese Evaluations of the U.S. Navy Submarine Force" and "CHINA’S FUTURE NUCLEAR SUBMARINE FORCE"

Those figures are useless without further information... are they top speed signatures, at rest signatures, low speed signatures?

A Kilo operating on electric drive at low speed (3-4knts) would make almost no noise.

Also ambient noise in the ocean depends on the place and time... whale song will change the ambient noise levels dramatically.

A busy shipping lane will also mask the noise of a hunting Kilo.... and more importantly there are half a dozen types of Kilo out there... which one are they talking about?

Do they know there is a difference... I suspect they don't because they are just pulling these numbers out of their ass.

Also isn't sound a log scale so the 15 Db difference between Akula and Virginia make the Virginia 150 times quieter?

BS.

GarryB wrote:Also isn't sound a log scale so the 15 Db difference between Akula and Virginia make the Virginia 150 times quieter?

BS.

You are quite right, db is based on log base 10.

For amplitude, A, the formula is 20*log_10(A/A0) dB. So the ratio between 110 dB and 95 dB is

10^(110/20) / 10^(95/20) = 316228/56234 = 5.6

So the Akula is supposedly almost six times noisier than the Virginia. That would be in the blogger's wet dreams.

Every new gen Sub reduces noise level by 5-6x times , The difference between noise level of Victor 3 and Akual 1 is around 3x time and between Akula1 and Akula 2 its around 3x times.

Ruby General Director did mentioned that borei was 5 times quiter than Akula and Oscar2

ПЛ пр.955 имеют в 5 раз меньшую шумность, чем ПЛА пр.971 и пр.949А (заявление генерального директора ЦКБ "Рубин" А.А.Дьячкова, 21.12.2010 г.)

5 times lower translates to translate to 7 dB reduction.

So Virginia being 6 times lower than Akula wont be surprising as there is generation jump.

I would think Yasen would achieve similar Noise Level as Virginia

Since 955A Borei would further achieve noise reduction you can expect 3-4x reduction in noise level

This report has been prepared by Lowy Institute, Australia

http://www.lowyinstitute.org/files/nuclear-armed-submarines-in-indo-pacific-asia-stabiliser-or-menace_0.pdf

While the report basically reflects upon the SSBN capabilities of China & India they also say that Russian submarines are more noisy than Western analogues. Is there any truth in it? Can you guys provide some estimated noise levels of US SSBNs?

I found the estimated noise levels for Russian SSBNs http://www.armscontrol.ru/subs/snf/snf03221.htm

http://manglermuldoon.blogspot.in/2013/12/chinas-anti-access-strategy-submarine.html

To provide a point of reference, the following acoustic signatures are from "Chinese Evaluations of the U.S. Navy Submarine Force" and "CHINA’S FUTURE NUCLEAR SUBMARINE FORCE"

Ocean background noise - 90 decibels
Seawolf-class - 95 decibels
Virginia-class - 95 decibels
636 Kilo class - 105 decibels
Akula-class - 110 decibels
Type 093 - 110 decibels
Type 094 - 120 decibels

Austin wrote:http://manglermuldoon.blogspot.in/2013/12/chinas-anti-access-strategy-submarine.html

To provide a point of reference, the following acoustic signatures are from "Chinese Evaluations of the U.S. Navy Submarine Force" and "CHINA’S FUTURE NUCLEAR SUBMARINE FORCE"

Ocean background noise - 90 decibels
Seawolf-class - 95 decibels
Virginia-class - 95 decibels
636 Kilo class - 105 decibels
Akula-class - 110 decibels
Type 093 - 110 decibels
Type 094 - 120 decibels

Could be interesting to know the speed/deep and propulsion mode (diesel or electrics) for these numbers.

Austin wrote:http://manglermuldoon.blogspot.in/2013/12/chinas-anti-access-strategy-submarine.html

To provide a point of reference, the following acoustic signatures are from "Chinese Evaluations of the U.S. Navy Submarine Force" and "CHINA’S FUTURE NUCLEAR SUBMARINE FORCE"

Ocean background noise - 90 decibels
Seawolf-class - 95 decibels
Virginia-class - 95 decibels
636 Kilo class - 105 decibels
Akula-class - 110 decibels
Type 093 - 110 decibels
Type 094 - 120 decibels

interesting how Chinese measured Seawolf/Virginia noise? no source provided or I am missing omething? all other sources are either US intel or authors nothing from China or Russia. Funny is that 677 is noisier than 636.6 built for China accorduing tho those sources

Which Akula they're talking about ? Because Los Angeles class SSN faces difficulties in finding 971-Akula SSN ( 90 db )

I think thats the only time I've seen actual numbers instead of scale-free graphs

I wonder which 636 they are supposed to be & how much difference there is between the versions?

Austin wrote:http://manglermuldoon.blogspot.in/2013/12/chinas-anti-access-strategy-submarine.html

To provide a point of reference, the following acoustic signatures are from "Chinese Evaluations of the U.S. Navy Submarine Force" and "CHINA’S FUTURE NUCLEAR SUBMARINE FORCE"

Ocean background noise - 90 decibels
Seawolf-class - 95 decibels
Virginia-class - 95 decibels
636 Kilo class - 105 decibels
Akula-class - 110 decibels
Type 093 - 110 decibels
Type 094 - 120 decibels

Nicely rounded numbers.
Submarine noise levels are closely guarded secrets by the military.
These figures have zero credibility. At least they should have not rounded numbers. Hey, if they had put decimals, it would have looked more credible.


Fools.

GunshipDemocracy wrote:

Austin wrote:http://manglermuldoon.blogspot.in/2013/12/chinas-anti-access-strategy-submarine.html

To provide a point of reference, the following acoustic signatures are from "Chinese Evaluations of the U.S. Navy Submarine Force" and "CHINA’S FUTURE NUCLEAR SUBMARINE FORCE"

Ocean background noise - 90 decibels
Seawolf-class - 95 decibels
Virginia-class - 95 decibels
636 Kilo class - 105 decibels
Akula-class - 110 decibels
Type 093 - 110 decibels
Type 094 - 120 decibels

interesting how Chinese measured Seawolf/Virginia noise? no source provided or I am missing omething? all other sources are either US intel or authors nothing from China or Russia. Funny is that 677 is noisier than 636.6 built for China accorduing tho those sources

It is more than that.

An electric submarine must generate less noise than a nuclear in electric mode.
It hasn't got cooling pumps, boiling water in the reactor and control roads in it.

Additionaly the cruisinf speed of the nuclear submarine higher than for the diesel/electric, means more noise at the same speed.


If the diesel works in diesel mode then OK, it is noisy ,but not in electric mode.

971 is Akula only ( talking about nato naming . )

Austin wrote:http://manglermuldoon.blogspot.in/2013/12/chinas-anti-access-strategy-submarine.html

To provide a point of reference, the following acoustic signatures are from "Chinese Evaluations of the U.S. Navy Submarine Force" and "CHINA’S FUTURE NUCLEAR SUBMARINE FORCE"

Ocean background noise - 90 decibels
Seawolf-class - 95 decibels
Virginia-class - 95 decibels
636 Kilo class - 105 decibels
Akula-class - 110 decibels
Type 093 - 110 decibels
Type 094 - 120 decibels

Ocean background sound is in the 55 to 85 dB range.   The rest of these number are similar trash.  The noise level is not
a constant but a function of submarine speed, local currents and turbulence if in the mixed layer, screw speed and power
plant operation regime.   A submarine that is "off" will not make any noise relative to the background.    Then we have
the peculiar properties of the thermocline at the base of the mixed layer where acoustic modes are refracted and ducted
horizontally.   It is layer where the background noise maximizes so a submarine sitting in this layer will be very hard to detect.
The 636 is specifically designed to cruise in this layer and when it operates in electric mode it really is a "black hole".   The
"105 dB" figure is retarded fantasy masturbation.

Austin wrote:http://manglermuldoon.blogspot.in/2013/12/chinas-anti-access-strategy-submarine.html

To provide a point of reference, the following acoustic signatures are from "Chinese Evaluations of the U.S. Navy Submarine Force" and "CHINA’S FUTURE NUCLEAR SUBMARINE FORCE"

Ocean background noise - 90 decibels
Seawolf-class - 95 decibels
Virginia-class - 95 decibels
636 Kilo class - 105 decibels
Akula-class - 110 decibels
Type 093 - 110 decibels
Type 094 - 120 decibels

To be fair the 110 is for the old Akula's.

The modernized ones are supposed to be quieter by how much well remains to be seen