INS Arihant (ATV) News and Discussion -2

Gagan
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Re: INS Arihant (ATV) News and Discussion -2

Postby Gagan » 03 Jun 2010 21:17

SNaik, chackojoseph,
working on it. 10 mins

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Re: INS Arihant (ATV) News and Discussion -2

Postby ramana » 03 Jun 2010 21:20

Gagan,
A request. Chatterati have always said the Arihant is based on Charlie class. So can you do a comparison to that and let us know? Also can you identify the number of tubes 4? If its four can you layout triple launchers in each tube for k15 dia making allowance for its launcher say 4 inches all around?

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Re: INS Arihant (ATV) News and Discussion -2

Postby Rahul M » 03 Jun 2010 21:24

ramana, the report that quoted the good V Adm mentioned 12 K-15 missiles. it was mentioned/surmised that for the larger dia K-X it will be only 4.

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Re: INS Arihant (ATV) News and Discussion -2

Postby Gagan » 03 Jun 2010 21:31

Wouldn't there be at least 2 side looking sonars along the body?

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Re: INS Arihant (ATV) News and Discussion -2

Postby Austin » 03 Jun 2010 21:46

Gagan wrote:Wouldn't there be at least 2 side looking sonars along the body?


Yes that should be there Passive Flank Arrays just being the bow.

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Re: INS Arihant (ATV) News and Discussion -2

Postby chackojoseph » 03 Jun 2010 21:50

Gagan,

I don't think there is a hump. The impression of hump came because of the concave surface behind the conning. Are you sure that the rear end of the portion is what they might have seen?

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Re: INS Arihant (ATV) News and Discussion -2

Postby Gagan » 03 Jun 2010 21:54

Yes Sandeep unnithan's drawing shows that kind of a rear end. The hump is visible in his drawing.
He was looking at it from a little behind the sail in his 1st drawing. then he went forward to do the 2nd one, and then on the port side for the final front drawing.

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Re: INS Arihant (ATV) News and Discussion -2

Postby Gagan » 03 Jun 2010 21:55

Ok here it is: click for larger image
Image

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Re: INS Arihant (ATV) News and Discussion -2

Postby Singha » 03 Jun 2010 21:58

UK is using a Thales sonar system in its latest subs. mainly a french co but with facilities in UK too probably. all of NATO could presumably buy and install that same system in their subs if they paid the price.

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Re: INS Arihant (ATV) News and Discussion -2

Postby ramana » 03 Jun 2010 22:02

So Gagan how long is the hump for that the payload container section? Can it fit the four tubes of say - AIII size? Or do you need to stagger them in plan view?

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Re: INS Arihant (ATV) News and Discussion -2

Postby chackojoseph » 03 Jun 2010 22:05

:D Gagan we are looking at a baby akula

Image

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Re: INS Arihant (ATV) News and Discussion -2

Postby chackojoseph » 03 Jun 2010 22:10

ramana wrote:So Gagan how long is the hump for that the payload container section? Can it fit the four tubes of say - AIII size? Or do you need to stagger them in plan view?


Ramana,

we can fit in Shaurya's (read K-15).

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Re: INS Arihant (ATV) News and Discussion -2

Postby KrishG » 03 Jun 2010 22:12

^^^ Isn't the missile bay in front of the sail in Akula class subs ? In contrast ATV has it behind the sail.

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Re: INS Arihant (ATV) News and Discussion -2

Postby Gagan » 03 Jun 2010 22:13

If the A3SL dia is 2m, The max that the tube will be will be 2.5-2.8m in dia.
4 tubes arranged linearly with say 1.5m space between each tube = 0.75+2.8+1.5+2.8 ...+2.8+0.75 = 17.2m

The hump should be ~ 18-20 m long at the minimum.

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Re: INS Arihant (ATV) News and Discussion -2

Postby chackojoseph » 03 Jun 2010 22:16

KrishG wrote:^^^ Isn't the missile bay in front of the sail in Akula class subs ? In contrast ATV has it behind the sail.


KrishG,

We am only trying to arrive at a possible likely design. IMHO, the design is most close to an Akula. One schematic of interior was done by India Today I guess.

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Re: INS Arihant (ATV) News and Discussion -2

Postby Gagan » 03 Jun 2010 22:16

chackojoseph wrote::D Gagan we are looking at a baby akula

Are you suggesting that the ATV seems to be a lot like an MKIsed Akula? :)

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Re: INS Arihant (ATV) News and Discussion -2

Postby Gagan » 03 Jun 2010 22:18

That India today interior might not be accurate. It seemed to be a taken from a US / British sub.
Didn't it show 4 trident C4 missiles?

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Re: INS Arihant (ATV) News and Discussion -2

Postby chackojoseph » 03 Jun 2010 22:24

Gagan wrote:
chackojoseph wrote::D Gagan we are looking at a baby akula

Are you suggesting that the ATV seems to be a lot like an MKIsed Akula? :)


IMHO. I was searching various Russian boats including Akula. That concave bend in the new photo and the India Todays pic gave me the idea. The explicit hump they saw was an impression, probably because it could have been submerged or less visible. As, I said IMHO.

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Re: INS Arihant (ATV) News and Discussion -2

Postby chackojoseph » 03 Jun 2010 22:27

Gagan wrote:That India today interior might not be accurate. It seemed to be a taken from a US / British sub.
Didn't it show 4 trident C4 missiles?


That's very indicative, IMHO. The arrangement of torp tubes, the conning, the silos, the reactors and the propulsion in that order. There might be variations for Indian requirements, but, the overall layout may not change.

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Re: INS Arihant (ATV) News and Discussion -2

Postby vasu_ray » 04 Jun 2010 00:03

do you guys think the missile tubes are placed single file or to be exact like a koko player arrangement? allowing for larger dia missiles in future

12 missiles need 3 times current length of the missile section

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Re: INS Arihant (ATV) News and Discussion -2

Postby Gagan » 04 Jun 2010 01:33

Consider this picture of the reactor.
This is the inner pressure hull. Notice the concentric rings around the hull. These are typical of a pressure hull.
Image

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Re: INS Arihant (ATV) News and Discussion -2

Postby Misraji » 04 Jun 2010 02:43

chackojoseph wrote:
Gagan wrote:That India today interior might not be accurate. It seemed to be a taken from a US / British sub.
Didn't it show 4 trident C4 missiles?


That's very indicative, IMHO. The arrangement of torp tubes, the conning, the silos, the reactors and the propulsion in that order. There might be variations for Indian requirements, but, the overall layout may not change.


Not really. As Gagan saar, had explained earlier, the sonar arrangement is different for US/Western submarines
vs Russian subs on the account of better signal processing available to the west.
That dictates the placement of torp tubes. Furthermore the types of torp-tubes, ram discharge vs
free-swimming (??) could effect the arrangement.
In the new Virginia class they have "photonic" masts instead of conventional periscopes.
Then there is the case of single hulled western subs versus the traditionally double-hulled russian subs.
All in all, imho, arrangement can be drastically be different between an existing western sub and Arihant.

~Ashish.

PS: Gagan saar, know that you haven't seen Arihant. Appreciate the effort you spent on the Arihant drawing .. :)

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Re: INS Arihant (ATV) News and Discussion -2

Postby Singha » 04 Jun 2010 08:19

akula has no VL tubes. the first Ru SSN with VL tubes is Graney. only other subs with vl tubes is 688i/nssn/seawolf.
optronic mast gives flexibility in internal layout because the periscope no longer is a physical tube and the control room
center need not be directly underneath the sail for the commander to use. he could get the periscope vision "piped" anywhere. the other masts like thermal camera, radar, rwr, radio anyways do not need physical connection to C3I room.

the absense of akula sail and the towed sonar on top of tail fin suggest its not akula derivative.

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Re: INS Arihant (ATV) News and Discussion -2

Postby geeth » 04 Jun 2010 10:49

Gagan,

Few observations on your drawing...

From the photo, I 'Judge' the outer hull dia (without the hump) to be about 14-15 metres. This is assuming that the person standing under the sail is about 6 ft tall. From published info, the length is about 110 metres, which gives a L/D ratio of 7.8.

Your drawing shows a L/D ratio of 10. If you make it 7.8, then the sub may look closer to actual size and shape.

The top surface of the hull aft of the conning tower appears to be horizontal for a length of about 5~7 metres, and then rises gradually to the hump. Make the hump length about 10 metres to accommodate 4 vertical tubes in two rows..(this is my speculation after reading published data, so you can correct accordingly)

See how it looks

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Re: INS Arihant (ATV) News and Discussion -2

Postby Gagan » 04 Jun 2010 12:24

Hump will be more than 10 m for sure. I estimated 18-20 m.
My current drawing in not to scale in any way. It is just based on very rough calculation using MS paint and a scale across my monitor.
I am trying to do this in photoshop.
Last edited by Gagan on 04 Jun 2010 12:37, edited 1 time in total.

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Re: INS Arihant (ATV) News and Discussion -2

Postby tsarkar » 04 Jun 2010 12:34

Gagan,

Your image posted 3rd June 21:55 comes closest, though I would suggest having a single incline from the forward missile turtleback all the way to the bow.

There is no reason for a prominent raised hump, because IN has ensure the missile fit the submarine, rather than the Russian practice of going the other way by adding a boxy turtleback to fit the submarine to the missile.

There is an appearance of a gentle turtleback because of the flattened casing to make handling easier.

Geeth,

My understanding is there are four 2 meter diameter tubes in a single row.

Reasons being the three submarines are essentially technology demonstrators with each successive submarine incorporating lessons learnt.

The design and constituent subsystems isn’t operationally proven and single row offers better ship handling and easier to design, rather than two rows with consequent handling and ballasting issues when larger 2 meter diameter missiles are fired.

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Re: INS Arihant (ATV) News and Discussion -2

Postby Philip » 04 Jun 2010 14:43

Some reports have suggested that there are 4 silos each carrying three missiles.Assuming that each missile is about 2-3ft (1m max) in diameter,it would require a silo of 2.4m (8'),with a passage of 1.2m (4') between them,placed side by side the two silos would then need just 6m width.In a sub whose hull is supposed to be nearer 12m (40'),the side by side location would be preferable particularly because later versions would require at least 8-12 silos for ICBMs with MIRVs,as each silo would carry only a single missile.The forward part of the sub resembles a stretched,larger Kilo,which indicates that the arrangement of the torpedo/sonar sections though larger are similar to the Kilo.The sub will definitely have at least 6 TTs,with perhaps two being larger diameter than std. 533mm,for Shkvals.Take a good look at a typical; Delta-4 class SSBN.One can see similarities with our ATV,especially with regard to the sail.(http://en.wikipedia.org/wiki/File:Delta ... s_SSBN.svg)
Remember Sandeep's first comments that the sub reminded him of a Cold War '70/'80s design.

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Re: INS Arihant (ATV) News and Discussion -2

Postby shiv » 04 Jun 2010 16:36

Gagan wrote:Hump will be more than 10 m for sure.


Can't resist
http://www.youtube.com/watch?v=iEe_eraFWWs

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Re: INS Arihant (ATV) News and Discussion -2

Postby chackojoseph » 04 Jun 2010 17:45

Misraji wrote:Not really. As Gagan saar, had explained earlier, the sonar arrangement is different for US/Western submarines vs Russian subs on the account of better signal processing available to the west.
That dictates the placement of torp tubes. Furthermore the types of torp-tubes, ram discharge vs
free-swimming (??) could effect the arrangement.
In the new Virginia class they have "photonic" masts instead of conventional periscopes.
Then there is the case of single hulled western subs versus the traditionally double-hulled russian subs.
All in all, imho, arrangement can be drastically be different between an existing western sub and Arihant.

~Ashish.

PS: Gagan saar, know that you haven't seen Arihant. Appreciate the effort you spent on the Arihant drawing .. :)


Could you please tell me how drastically different it will be?

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Re: INS Arihant (ATV) News and Discussion -2

Postby chackojoseph » 04 Jun 2010 18:00

If you don't consider the conning and adjust the fat front to finess, the sub should look like this

Image

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Re: INS Arihant (ATV) News and Discussion -2

Postby negi » 04 Jun 2010 18:04

^ Boss in case of RU subs the torpedo tubes are right on the frontal hemisphere (anywhere from 6 or even more) in case of Akulas even the countermeasure dispensers are located in the same region (above the torpedo tubes) which means the section of the hull right after the frontal region might house the torpedo room and stowage for the countermeasures. Unkil's subs have the torpedo tubes located on either flanks so the fore section of the hull is freed up (LA class and Virginia have 12 VL tubes in that region for Tomahawk LACMs) the frontal hemisphere itself houses the spherical sonar transducer array.

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Re: INS Arihant (ATV) News and Discussion -2

Postby chackojoseph » 04 Jun 2010 18:11

negi wrote:^ Boss in case of RU subs the torpedo tubes are right on the frontal hemisphere (anywhere from 6 or even more) in case of Akulas even the countermeasure dispensers are located in the same region (above the torpedo tubes) which means the section of the hull right after the frontal region might house the torpedo room and stowage for the countermeasures. Unkil's subs have the torpedo tubes located on either flanks so the fore section of the hull is freed up (LA class and Virginia have 12 VL tubes in that region for Tomahawk LACMs) the frontal hemisphere itself houses the spherical sonar transducer array.


What about Brit and french?

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Re: INS Arihant (ATV) News and Discussion -2

Postby Singha » 04 Jun 2010 19:26

anypme who uses the american style giant sphere sonar has the nose locked up and needs angled torpedo tubes behind it.
british have used their usual chankian tactics and tallboy santro design to put the thales sonar on top and torpedo tubes at the
bottom of the nose a bit behind the sonar
http://3.bp.blogspot.com/_J0gDkDskVlA/S ... 23376c.jpg
http://www.royalnavy.mod.uk/upload/pdf/ ... _image.pdf
the french as is the norm, have done the exact opposite of the british for their barracuda SSN - torps on top, sonar on bottom!
http://www.naval-technology.com/project ... cuda2.html

methinks Sher khan can afford it because they really have no limit on how big their subs can be - costwise or reactor power wise. so stick a humongous sonar in front and add 10m length to get the torpedo room behind it. the poorer Munna's have to watch the overall size also.

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Re: INS Arihant (ATV) News and Discussion -2

Postby Patrick Cusack » 04 Jun 2010 20:17

It is possible that INS Arihant was already in trials 1/2 years ago and top brass did was attend commissioning ceremony-
How else can they justify replicating 2 or 3 more already!!!!!!!!! :D

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Re: INS Arihant (ATV) News and Discussion -2

Postby Gagan » 04 Jun 2010 20:41

Two versions of the 'hump' and the forward slope.
Ver 14
Image

Ver 15
Image

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Re: INS Arihant (ATV) News and Discussion -2

Postby sgopal » 04 Jun 2010 20:46

Is'nt Arihant's sonar spherical?

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Re: INS Arihant (ATV) News and Discussion -2

Postby shiv » 04 Jun 2010 21:05

Gagan wrote:Two versions of the 'hump' and the forward slope.


Gagan - to my eyes this one looks right

http://img163.imageshack.us/img163/5818/atv6.jpg

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Re: INS Arihant (ATV) News and Discussion -2

Postby Craig Alpert » 04 Jun 2010 21:11

Question - In all the renderings by Gagan there are antennas and persicopes shown, how come (to me) it wasn't visible when the pic was released in the Report Card?? Am I not seeing what i'm suppose to be seeing or is it just the lightinig effect in the pic, or do all these antennas actually retract down when Arihant is powered down???

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Re: INS Arihant (ATV) News and Discussion -2

Postby Kanson » 04 Jun 2010 21:12

Gagan wrote:Two versions of the 'hump' and the forward slope.
Ver 14
http://img101.imageshack.us/img101/2772/atv14bsmall.jpg

Ver 15
http://img706.imageshack.us/img706/4135/atv15small.jpg


Going by the contours of the L&T published Arihant image published in major dailies, Ver 14 looks close. From Nose cose to the conn. tower the slope gradient is sharp, as i see it, and similar to the Sea wolf. Nose section of Sea wolf from similar angle, http://www.ssbn611.org/images/USS%20Jim ... ter-47.jpg.

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Re: INS Arihant (ATV) News and Discussion -2

Postby Kanson » 04 Jun 2010 21:15

sgopal wrote:Is'nt Arihant's sonar spherical?


I guess, the current Arihant nose cone is based on Akula, so whatever Sonar Akula supports can be expected in Arihant. This is for current Arihant only.


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