Indian Naval Discussion

rajsunder · Post by **rajsunder** » 10 Jul 2009 00:47

negi wrote:diesel electrical ones are silent killers, far silent than any nuke one could ever be.
That is False.

any supporting info

hnair · Post by **hnair** » 10 Jul 2009 00:51

diesel ones are easier to live with, going by their lifecycle costs, easy to maintain and decommission/dispose. A large establishment is required to keep those reactors safe (from accidents + pakis), especially when they are (dry)docked.

For a brown-water defensive navy, the diesel's range is fine. But if you want to plop a baby boomer far from shore, it is best to have it surrounded by akulas, a vicky-sized carrier and P8s with customized gear. heavy stuff that costs too much money, but has to be done.

suryag · Post by **suryag** » 10 Jul 2009 01:02

Diesel-electric subs have their own place in the field and complement nuke subs. After all, we dont have unending supplies of nuclear fuel to may be maintain say 12-14 subs.

p_saggu · Post by **p_saggu** » 10 Jul 2009 01:13

Diesel electric subs are quiet only when the sub runs on battery power - which it has to when underwater. Not so when l'french subs turn on le MESMA, where the l'oxygen cylinder runs the diesel engine underwater.
In the nuclear sub, battery power is also an option, however because of the usually larger size, maintaining the inside environment, and propulsion is more power hungry. Add to this that the boiling hot reactor is always boiling steam in high pressure, which I'm sure generates sounds of its own.

khukri · Post by **khukri** » 10 Jul 2009 01:42

hnair wrote:diesel ones are easier to live with, going by their lifecycle costs, easy to maintain and decommission/dispose. A large establishment is required to keep those reactors safe (from accidents + pakis), especially when they are (dry)docked.

For a brown-water defensive navy, the diesel's range is fine. But if you want to plop a baby boomer far from shore, it is best to have it surrounded by akulas, a vicky-sized carrier and P8s with customized gear. heavy stuff that costs too much money, but has to be done.

Thank you armchair admiral for that enligtening discourse on naval deployment - the whole purpose of boomers as a deterrent is to keep them hidden, not highlight their presence by adding a carrier battle group around them so even Stevie Wonder wouldn't have a problem locating them.
Boomers travel alone!

negi · Post by **negi** » 10 Jul 2009 02:01

The modern nuclear subs are equipped powerplants which employ 'mixed/hybrid' circulation i.e. both forced/natural circulation so when a sub is operating in ultraquiet mode it can actually swicth off its coolant pumps and still operate the reactor at a significant high proportion of its power. The entire range of 8th Generation and above family from westinghouse and GE employ this feature (afaik Ohio and Virginia class are both powered by S8G and S9G respectively).

The turbines too instead of using 'superheated' steam are powered by 'saturated' steam which again means a more compact HE design with lesser dependence on pumps.

However nuclear subs have practically unlimited endurance and can nicely hide amongst the 'thermals' in deep ocean ; the major proportion of a subs acoustic signature is contributed by the hydrodynamic drag which is independent of propulsion technology .

hnair · Post by **hnair** » 10 Jul 2009 03:26

After flushing down the offal and filth.....

khukri wrote:the whole purpose of boomers as a deterrent is to keep them hidden, not highlight their presence by adding a carrier battle group around them so even Stevie Wonder wouldn't have a problem locating them.
Boomers travel alone!

they cant be left alone - our first generation SLBMs dont yet have the range required for boomers to be far away from enemy MPAs and coastal submarines. Nor do we know about their accuracies from a sub launch yet.

Hitesh · Post by **Hitesh** » 10 Jul 2009 03:44

NRao wrote:FT :: India set to launch nuclear submarine

The country lags behind China's naval might in the region. C. Uday Bhaskar, director of the Delhi-based National Maritime Foundation, said Beijing had a fleet of eight nuclear submarines, some with ballistic missile capability. The Chinese navy has three times the number of combat vessels (about 630) as India and five times the personnel.

Most of the chinese navy (75%) can't even venture out of China's coastland for more than 50 miles and the bulk of the navy personnel remains on the mainland, not even having any maritime experience so i wouldn't worry too much about the supposed numerical superiority that PLAN has over IN.

Raveen · Post by **Raveen** » 10 Jul 2009 04:04

^^^
Love the confidence
Hate the lack of sources

khukri · Post by **khukri** » 10 Jul 2009 06:34

hnair wrote:After flushing down the offal and filth.....

khukri wrote:the whole purpose of boomers as a deterrent is to keep them hidden, not highlight their presence by adding a carrier battle group around them so even Stevie Wonder wouldn't have a problem locating them.
Boomers travel alone!
they cant be left alone - our first generation SLBMs dont yet have the range required for boomers to be far away from enemy MPAs and coastal submarines. Nor do we know about their accuracies from a sub launch yet.

That's right, so a potential enemy can take out the entire battle group with one surgical strike, including the first use of nuclear weapons, justifying that on the grounds that a boomer was part of the group.

The Chinese are already arming themselves with such weapons in anticipation of neutralising US carrier battle groups in a potential confrontation over Taiwan.

The whole purpose of having submarines, not just boomers, is to hide your assets, not to advertise their presence by adding bells and whistles and a neon sign indicating their approximate location!

(Look ma - no filth and offal!)

Raj Malhotra · Post by **Raj Malhotra** » 10 Jul 2009 08:39

I am ready to bet that ATV would be modernized Akula i.e. Akula-III=Sverdinsk MKIsed.

Austin · Post by **Austin** » 10 Jul 2009 09:43

Between a conventional submarine and a nuclear submarine of same generation , a conventional submarine will always be more silent specially when its running on battery compared to a nuclear submarine operating in ultra quite.

But silence is just one part of matrix , for speed , range , capability of sensor suite and weapons a nuclear submarine far outclasses any conventional submarine even when AIP equipped.

negi · Post by **negi** » 10 Jul 2009 09:44

^ Would you say this for the modern Kilo and the Akula too..... Austin ?

Austin · Post by **Austin** » 10 Jul 2009 10:10

negi wrote:^ Would you say this for the modern Kilo and the Akula too..... Austin ?

Yes why not , a 636 Kilo is a very difficult target to detect as put across by western literature and US Congress topic on the subject , An Akula-2 may be slightly noisier but its Huge Passive Sonar Suite and Non Acoustic Sensor suite will probably detect a Kilo much earlier than a Kilo would for an Akula , all conditions being equal.

I remember looking at Graph by US Congress which rated the Lada acoustic quietening at ~ 80- 90 db which was rated similar to Seawolf quietening , but I am certain all conditions being equal a SeaWolf sensor suite would have a good chance to detect a Lada first and execute a firing solution at it. Silence is critical but one part of the matrix.

Vinito · Post by **Vinito** » 10 Jul 2009 10:17

rajsunder wrote:
Nihat wrote:Why bother with diesel subs anymore or is there a distinct advantage which diesel electric propulsion subs hold over nuke subs.
diesel electrical ones are silent killers, far silent than any nuke one could ever be.

BTW Russian kilos are nicknamed black holes for their silence.

I believe that the Russian Kilos were called black holes for their silence at the time when the competition was quite low and the only competitors were the HDW 209 type of submarines. They no longer hold the edge when they are pitched against the new AIP equipped generation of submarines e.g. Scorpene, U212 & U214 subs which has also led the Russian to adopt the same methods leading to the new generation of Amur class subs. However they are still not that silent anymore given the new types of electronics being loaded on the competition.

negi · Post by **negi** » 10 Jul 2009 10:42

Kilo's were never known for their low acoustic signatures afaik it is only the new models which are equipped with the latest 7 bladed skewed propeller have improved performance the old one's had a 4/6 blade propeller which was pretty noisy .

The way the sonar operator or even Sonar tries to distinguish between a Sub or any other moving body in water is by analysing the low frequency component of the received signal in case of Subs the RPM of the propellers generates a LF noise which is audible to a modern sonar for miles infact one can make out the number of blades of the sub by analysing the signal.

Machining and balancing Sub props is a closely guarded secret and obviously a costly process the sheer numbers in which Kilos are made and exported and given the RU's reputation for producing goods which demand 'precision' and 'tolerance' I don't think Kilo's have much to brag about their acoustic performance. The anechoic tiles and other stuff is pretty much a global std these days .

Austin · Post by **Austin** » 10 Jul 2009 11:02

That is right negi , it required a lot of effort and learning and quality control in every aspect even for the US Industry and Yards to build machine of fine tolerence and precision which helped in drastic reduction of narrow band tonal , the nemesis of Soviet submarine build until late 70's , similarly when the Soviets came to know about this it took a similar herculian effort to reduce its narrow band tonals , hence improvement and scientific achievement was always added on the way when similar class of submarine were built like the first kilo to the last Kilo 636 or from Akula-1 to Akula-3

One invention and perfection done by Soviet was in the field of active noise reduction , according to norman polmar when implemented properly it would achieve a noise reduction of 30 to 40 dB compared to similar subs which does not have it. Akula subs do have these active noise reduction systems in them.How to implement such active noise reduction is ofcourse a trade secret.

Kersi D · Post by **Kersi D** » 10 Jul 2009 11:06

p_saggu wrote:Diesel electric subs are quiet only when the sub runs on battery power - which it has to when underwater. Not so when l'french subs turn on le MESMA, where the l'oxygen cylinder runs the diesel engine underwater.
In the nuclear sub, battery power is also an option, however because of the usually larger size, maintaining the inside environment, and propulsion is more power hungry. Add to this that the boiling hot reactor is always boiling steam in high pressure, which I'm sure generates sounds of its own.

Boiling high pressure steam does not produce any noise. In a N sub the maximum noise is produced by the coolant pumps. The USN subs can operate without running the coolant pump at very low speeds, and hence are very silent. I do not know if this feature exists with all subs.

A D-E subs can simply shut off all machinery and lie at the sea bottom and can be extremely difficult to detect. But most N subs have to have some machinery in operation and hence radiate some noise

K

Singha · Post by **Singha** » 10 Jul 2009 11:29

if the livefist ppt is a true side view, its based on the Victor-III/Akula general design including the big towed array housing and blended sail.

also note no humpback section, which means its a fairly big submarine.

but it could be just a placeholder ppt icon.

Vinito · Post by **Vinito** » 10 Jul 2009 11:38

negi wrote:Kilo's were never known for their low acoustic signatures afaik it is only the new models which are equipped with the latest 7 bladed skewed propeller have improved performance the old one's had a 4/6 blade propeller which was pretty noisy .

The way the sonar operator or even Sonar tries to distinguish between a Sub or any other moving body in water is by analysing the low frequency component of the received signal in case of Subs the RPM of the propellers generates a LF noise which is audible to a modern sonar for miles infact one can make out the number of blades of the sub by analysing the signal.

Machining and balancing Sub props is a closely guarded secret and obviously a costly process the sheer numbers in which Kilos are made and exported and given the RU's reputation for producing goods which demand 'precision' and 'tolerance' I don't think Kilo's have much to brag about their acoustic performance. The anechoic tiles and other stuff is pretty much a global std these days .

Is there any reason why the Russians dont use pumpjet propulsion instead of skewed propellors on their attack submarines? Most of the newer class of British & American attack subs use the pumpjet propulsion. Even the Russian Borei class SSBN has been listed as having this.

Singha · Post by **Singha** » 10 Jul 2009 11:48

they must have lagged behind in 90s due to lack of funding. a prototype
was tested on a kilo - photo is on web somewhere.

negi · Post by **negi** » 10 Jul 2009 12:07

Afaik the pump jet needs high power as compared to a conventional propeller ; as it is the usp of the pump jet is a comparable hydrodynamic noise to a propeller driven sub albit at higher speeds .This obviously rules out Diesel-electric subs out ; there are schematic/artist's impressions of Borei with a pump jet propulsor however the official site of RUBIN Engg has this pic

I guess since this is a SSBN it must be using a single 7 bladed propeller onlee.

--removed the obvious

--

kittoo · Post by **kittoo** » 10 Jul 2009 12:10

Raveen wrote:^^^
Love the confidence
Hate the lack of sources

Exactly.

Shankar · Post by **Shankar** » 10 Jul 2009 12:26

Boiling high pressure steam does not produce any noise. In a N sub the maximum noise is produced by the coolant pumps. The USN subs can operate without running the coolant pump at very low speeds, and hence are very silent. I do not know if this feature exists with all subs.

a technically incorrect statement -how can you boil steam you can only boil water -right

in a pressurized water reactor of a nuclear sub water is not allowed to boil plain and simple just like a pressure cooker - elevation of boiling point of water as it is kept under pressure as much as 17o-210 times atmospheric allows the circulating water to extract heat from fission reactor core to a separate steam generator where steam is produced to run the turbine and drive the screw/screws or generate power to drive motors .

Coolant pump is unavoidable in a nuclear sub - natural circulation is just not enough - it for emergency purpose only to take out the decay heat when the reactor is shut down and even then not always enough so diesel generators are provided in all nuke subs to keep the coolant pumps running when the ractor is under shut down

ovein · Post by **ovein** » 10 Jul 2009 12:28

Nerpa is in the water again.

http://en.rian.ru/mlitary_news/20090710/155488668.html
http://www.itar-tass.com/eng/level2.htm ... &PageNum=0

The nuclear-powered submarine Nerpa left the Vostok plant, the city of Bolshoi Kamen (the branch of the Amur ship repair plant in the Primorsky Territory) for the Sea of Japan on Friday for the second-time testing, an Amur plant source told Itar-Tass

Shankar · Post by **Shankar** » 10 Jul 2009 12:38

The energy extraction from fission reaction in any pressurized water or even molten metal (mixture of lead bismuth) type reactor takes place in stages .The primary heat extraction circuit say uses high pressure water at 170 bar or more extracts heat from the reactor core by circulating through the fuel and control rods and the neutron reflectors as water (not as steam ). This water then goes to a steam generator which is essentially a shell and tube type heat exchanger where the tubes carry the high pressure water and the shell is filled with low pressure water but having a much higher volumetric flow . The low pressure water exits into a flash drum where steam is released and taken to the turbine linked to the screw through a gear box and also to a generator to provide power for all needs from weapons to water desalination to carbon di oxide scrubbing and heating coffee . The exhaust from the turbine contains a mixture of steam and water is condensed in a sea water cooler and fed back as feed to steam generating heat exchanger .Obviously some water is lost in the process which is made up from the desalinated water tank in the sub.

Shankar · Post by **Shankar** » 10 Jul 2009 12:47

Afaik the pump jet needs high power as compared to a conventional propeller ; as it is the usp of the pump jet is a comparable hydrodynamic noise to a propeller driven sub albit at higher speeds .This obviously rules out Diesel-electric subs out ; there are schematic/artist's impressions of Borei with a pump jet propulsor however the official site of RUBIN Engg has this pic

pump jet is effective only at high chase speed when the lamp shade type ducting delays the onset of cavitation noises and also suppresses the lateral transmission of acoustic signature

at slow speed a ducted prop is not energy efficient and no significant reduction in noise at low speed -thats why not much favored today

vina · Post by **vina** » 10 Jul 2009 13:17

pump jet is effective only at high chase speed when the lamp shade type ducting delays the onset of cavitation noises and also suppresses the lateral transmission of acoustic signature

Pump jet is just a multi stage pump. What it does is, it lowers the power absorbed per screw and hence has much better cavitation performance.

A close approximation is a ducted propeller (like on tugs), albeit with multiple screws. The duct cross section has an airfoil shape and the lift generated increases thrust for a given RPM , over a non ducted screw.

The additional advantage is that the duct can be a shield against nets, cables and other stuff that can foul the screws and bring the sub to a dead halt.

at slow speed a ducted prop is not energy efficient and no significant reduction in noise at low speed -thats why not much favored today

Ducted props are less efficient PERIOD. The ducts increase friction resistance and the overall efficiency will be less (a few points less) than an open prop.

Singha · Post by **Singha** » 10 Jul 2009 13:35

>> not much favoured

every new western sub class seems to have it?

Shankar · Post by **Shankar** » 10 Jul 2009 14:50

correct and even latest russian boomers are pump jet type which will be firing topol naval version - but all of them have very advanced reactor design and compact so can take on incremental shaft hp requirement easily - but pump jet has its own set of problems too

Philip · Post by **Philip** » 10 Jul 2009 17:33

There are different sub design philosophies between east and west.There are some books on the subject for detailed research if need be,but the designs also come with differing strategies and tactics for each side.Russian boomers were designed to operate within sanitised bastions,thanks to their geographical limitations,where their subs could not venture out into open oceans directly but had to transit through smaller seas and choke points.The Typhoon design is a singular example.It is only in the Pacific,Vladivostok, and parts of the Artic Sea that allows Russian subs to depart from their bases without detction.Even in the Pacific,thanks to the Japanese islands,the US has installed a large network of udnerwater hydrophones to detect Russian subs leaving and entering their bases,before they break out.How successful either side has been at avoding detection is debatable,as Russia had huge information about these networks thanks to the various intel ops they had running during the Cold war.

India is in a similar situation as the US,where both on the eastern and western seaboards,our subs can exit without transiting any choke points into the IOR.We have few areas where sub bastions can also be created,which can be well protected by air and naval forces.Thus our SSBNs will have to be designed in manner that they can also fight back if threatened by any other naval force,surface or subsurface.With our decades of extensive hydrographic research in the IOR especially in our EEZ,there would be underwater formations,ridges and mountains where our SSBNs can hide undetected.The presence of US nuclear subs and LRMP aircraft at Diego Garcia is one area of concern regarding detction of our SSBNs.We can expect more regular patrols of the Indian seaboard,and our naval bases from both east and west in the future.

pkudva · Post by **pkudva** » 10 Jul 2009 18:06

Guys, i am very happy to see the interest guys are showing in this form regarding the launching of the ATV and being a part of this programme i can only say that you will finally get to hear good news soon.

Nothing much.Enjoy and continue the discussion.

bala · Post by **bala** » 10 Jul 2009 21:33

This report says that Nerpa is under Gorshkov package deal..

Russia resumes pre-delivery trials of nuclear sub for India

Moscow (PTI) Russia on Friday resumed sea trials of its Akula class nuclear attack submarine to be leased to the Indian Navy, months after they were halted following an accident that killed 20 crew and staff members.

The Akula II class submarine was cleared for final sea trials before being commissioned with the Russian Navy and leased to the Indian Navy by end of 2009.

The submarine is to be leased to India for 10 years under a secret clause of the larger Gorshkov package signed in 2004.

"The sea trials of the Nerpa nuclear submarine will continue for two weeks. All damage on the vessel found during the investigation of the accident has been repaired," a defence official was quoted as saying by RIA Novosti.

The trials were halted after 20 crew members and technical staff of the shipyard were killed and 17 injured in the accidental triggering of fire suppression system filled with highly toxic Freon gas in the sleeping quarters on November 8, while the submarine was in the Sea of Japan.

India reportedly paid USD 650 million for a 10-year lease of the 12,000-ton K-152 Nerpa, considered the quietest and deadliest of all Russian nuclear-powered attack submarines.

'Human error' was identified as the cause of the worst accident on Russian submarines since the sinking of the Kursk in August 2000, in which 118 crew members were killed after a blast in the torpedo room.

KrishG · Post by **KrishG** » 10 Jul 2009 21:37

pkudva wrote:Guys, i am very happy to see the interest guys are showing in this form regarding the launching of the ATV and being a part of this programme i can only say that you will finally get to hear good news soon.

Nothing much.Enjoy and continue the discussion.

Prasad, Can't you give us some exclusive sneek-peeks ?? Please!

k prasad · Post by **k prasad** » 10 Jul 2009 22:06

<-- Edited after clarification -->

Look at Hazira on Wikimapia or Google Earth... there is some interesting stuff there (which is cross referenced from news sources).

Rahul M · Post by **Rahul M** » 10 Jul 2009 22:08

edited.

k prasad · Post by **k prasad** » 10 Jul 2009 22:19

Rahul M wrote:KP, read the quoted part in krish' post.

Aah... thanks... I confused pkudva with Prem Kudva from wiki...

pkudva · Post by **pkudva** » 10 Jul 2009 23:29

As of now i dont think it will be proper on my part to talk about it publicly.
But when i am a part of this forum,i wanted to share this news with u guys otherwise all these days i wanted to keep this info with me.This carries lots of importance.

Katare · Post by **Katare** » 10 Jul 2009 23:47

So the launch rumors are for real?

Vinito · Post by **Vinito** » 10 Jul 2009 23:54

Singha wrote:>> not much favoured

every new western sub class seems to have it?

Practically all new western class nuclear attack subs e.g. Astute, Seawolf, Virginia, Triomphant and I guess more