INS Arihant (ATV) News and Discussion -2

srai · Post by **srai** » 15 May 2013 11:33

^^^

Karwar -> 11,000 acres

NAOB -> 7,500 acres

Singha · Post by **Singha** » 15 May 2013 11:37

iit kanpur - 1100 acres
iit kharagpur - 2100 acres

so 7500 acres is big enough for anything.

Rishirishi · Post by **Rishirishi** » 17 May 2013 22:34

Singha wrote:iit kanpur - 1100 acres
iit kharagpur - 2100 acres

so 7500 acres is big enough for anything.

Why is IIT given such huge lands.

For comparison

Mumbai arport 1500 acres and IGI airport is 5200 acres

Singha · Post by **Singha** » 17 May 2013 22:42

Mumbai airport is small...it cannot be a benchmark.

Most older iit like kanpur are actually soon going to run out of space...whatever was open rambling grassland a decade ago is now taken over for new hostels, married student quarters, new academic areas , more staff quarters to accomodate growth. Sure there will be good fields and open spaces but not the kind of fallow land that once was. Unlike a foreign campus, pretty much 100% of indian students upto post doc level , as well as faculty live on the campus....so a lot of housing is needed. Delhi iit with its tiny campus is perenially short of faculty housing i think.

An alternative is to build highrise hostels but that goes against the old heritage look of campus and needs more electricity to run lifts and such. Still, a lot of new hostels are more highrise type incl in nit warangal and a swank new hostels in iit mumbai
Compare the higher number hostels to the low ones

http://www.iitb.ac.in/students/hostels.html

SaiK · Post by **SaiK** » 18 May 2013 01:09

If we don't give the space for education, the future will s(t)ink. /OT

Sagar G · Post by **Sagar G** » 26 May 2013 01:15

What do you see in these pics ???

member_26965 · Post by **member_26965** » 26 May 2013 10:07

Another news not posted here

Indian nuclear submarine INS Arihant features environment friendly water mist fire suppressants

http://frontierindia.net/indian-nuclear ... ppressants

The DRDO technology was validated for INS Arihant submarine in real scale 590 m3 cylindrical submarine fire simulation chamber. The simulation chamber was simulated as nuclear submarine compartment having four decks.

Austin · Post by **Austin** » 26 May 2013 12:32

Water mist fire suppressants , is it better from inert gas they use on ships and subs ?

member_26965 · Post by **member_26965** » 26 May 2013 12:56

I don't know boss. I more interested in someone analyzing "real scale 590 m3 cylindrical" submarine fire simulation chamber. The simulation chamber was "simulated as nuclear submarine compartment having four decks."

NRao · Post by **NRao** » 26 May 2013 12:58

Inert gases deprive the fire of oxygen and thus extinguish it. But in the process they also could - as it happened on the K-152 Nerpa - kill people who are not prepared. The advantage with inert gases is that they do not damage anything. Lives are at great risk. (I recall our data center used to have Halon. We had 15 secs to get out once the unique siren sounded.)

While water is more people friendly, but comes at the cost of damaging electronics, etc. Prior to inert gases (actually halon) the preferred method was water sprinklers, so they have got to be fairly effective.

So, I guess the IN, in the event of a fire onboard this ship, prefers to save lives and replace the material at some cost. Must be effective for the IN to approve it.

Singha · Post by **Singha** » 26 May 2013 13:02

The stuff needed for a emergency surface are probably redundant and sealed from water. Better that than lose 20 people i think...the nerpa accident must have convinced in.

member_26965 · Post by **member_26965** » 26 May 2013 15:01

May be not for the whole submarine, only selective parts.

SNaik · Post by **SNaik** » 26 May 2013 15:04

Austin wrote:Water mist fire suppressants , is it better from inert gas they use on ships and subs ?

Reminds me of environment-friendly heat insulation for Vikra's boilers.

Sagar G · Post by **Sagar G** » 26 May 2013 16:56

pandyan wrote:Would Water mist work for electrical fires?

Yes

NRao · Post by **NRao** » 26 May 2013 20:45

Singha wrote:The stuff needed for a emergency surface are probably redundant and sealed from water. Better that than lose 20 people i think...the nerpa accident must have convinced in.

In that case they should have thought about, planned and implemented it from the very start. I am not too sure, but, I would imagine it would be a task to retrofit such things without the huge additional cost. ?????

SNaik wrote: Reminds me of environment-friendly heat insulation for Vikra's boilers.

IIRC Hallon has been banned - it depletes the ozone layer. Outside of old units which have been in place for decades no new systems use Hallon. They have replaced it with inert gases, such as Freon - the one used on the Nerpa.

But all of them are very dangerous.

Sagar G wrote:
pandyan wrote:Would Water mist work for electrical fires?
Yes

They use foam for oil related fires?

Sagar G · Post by **Sagar G** » 26 May 2013 22:15

NRao wrote:They use foam for oil related fires?

The water mist system is qualified for both A and B class of fire as well as can be safely used against live electrical equipment as can be read here and here. The latter one had a ToT for the same from CFEES.

Kersi D · Post by **Kersi D** » 29 May 2013 12:53

NRao wrote:
IIRC Hallon has been banned - it depletes the ozone layer. Outside of old units which have been in place for decades no new systems use Hallon. They have replaced it with inert gases, such as Freon - the one used on the Nerpa.

But all of them are very dangerous.

They use foam for oil related fires?

Mr Rao. Freon IS one of the halons.

I believe that high pressure water mist can be used against electrical fires e.g. transformer. I think CO2, carbon dioxide, is also used against electrical fires.

K

vina · Post by **vina** » 30 May 2013 06:21

Today's Al-Hundi says in the front page that Arihant's reactor to go critical next week. So all the trials (except for the nuke propulsion) are done and satisfactory and all systems should be fine.

Brando · Post by **Brando** » 04 Jun 2013 02:34

It's "NEXT WEEK" - are we there yet ??

Katare · Post by **Katare** » 04 Jun 2013 02:42

Will it be critical in one go or Navy's going to say this is only Critical -1 and DRDO will say we'll get Critical-II done by end of the year followed by fonal critical next year?

Philip · Post by **Philip** » 04 Jun 2013 03:48

Reg. the VLS silos and capacity.The USN is adopting a new system of large silos in single file along the sub's centreline fore and aft of the sail.Each silo can house 7 Tomahawk type missiles and is meant to give the USN approx. the same capability on its modified Virginia class SSNs when its converted Ohio class (SSBNs into SSGNs) are retired.During the Libyan campaign,just one US sub fired 90+ Tomahawk missiles! This concept differs from the current practice of having two rows of silos as in SSBNs.

Now in an above post we have been given info that the ATV has "four decks".This means that the hull diameter is approx 40 ft./12m.Therefore,an Indian SSGN can have missile silos of 12m length,with a single hatch cover from 2.5 dia. upwards to house 7 missiles. The specs of Brahmos are 2.8m X 0.6.Thus we can easily fit 7 of this type and also 7 Nirbhays.In fact,Nirbhay's given dia. is less than that of Brahmos and so is its length at 6mX 0.52m. If we take the K-15,we have specs of 10m X 0.74m (2.4ft).Now this would easily accommodate the K-15,where we already have 4 silos housing 6 missiles each. But if the centreline concept is used,the missile diameter could be substantially increased giving us a larger missile with a greater range and payload if required.Since the missile compartment is a module,our ATVs could have either the current silo system or in the future also have a centreline silo system if required.

The only Qs one has are the quieting factor of opening a larger hatch prior to launch,take a dekko at the size of Soviet Typhoon class SSBN sub's hatches in this link (http://rwhiston.wordpress.com/2011/10/17/10/) and that centreline silos require a longer sub,which the USN favours. Russian designs seem to prefer less lengthy fatter subs,perhaps because they have double hulls.We've seen recently the problems the Spanish are having with their S-80 version of the Scorpene which needs a longer hull if it is not going to vist Davy Jone's Locker on a one way trip!

Singha · Post by **Singha** » 04 Jun 2013 11:33

afaik for any sub launched missile or torpedo the tube is first filled quietly with water to equalize pressure and then only hatch will open. if the system is smooth should not create a big noise signature.

merlin · Post by **merlin** » 04 Jun 2013 11:36

I always wondered what would happen to the other missiles in a multi missile silo when they are not fired. The silo will flood and then pumping out the water after closing the silo hatch would make noise wouldn't it?

Austin · Post by **Austin** » 04 Jun 2013 12:22

The noise part is a lot exaggerated stuff and comes from Hollywood movies where even the opening of hatch is heard and legendary stuff like that .....the reality is in a submarine there are other things that makes more noise that can be heard long distant.

Launching an SLBM is a very complex exercise and the sub suddenly looses couple of tons even from single launch and it has to be controlled via ballasting and de-ballasting to avoid stability issues and subs need to be trimmed and kept on course , launch in salvo mode of 2-3 SLBM gets even more nerve racking. you also have to follow certain pattern during mass salvo launch which is circular read to keep the error at minimal

The only time a SSBN ever launched its full salvo of SLBM was Delta 4 in 91 with 16 SLBM launches in under few minutes "During this 3.7 minutes the submarine expelled more than 650 tons of weight. Its been well documented in this video

operation begemot http://youtu.be/ath0oT-4bns

Philip · Post by **Philip** » 04 Jun 2013 14:43

There are both hot and cold launch options.It would be perhaps minimal when in safe waters,but in an environment where there are enemy subs around,especially in confined waters,stealth is the priority.The moment a missile is launched,a reference point as to the sub's location can be found,esp. if there are maritime sats available.

A US view of cold launch by its subs .

http://xbradtc.com/2013/05/07/cold-launch/

here are two ways to get a silo stored missile out of the silo (though in the case of subs, they’re called tubes, not silos), hot launch and cold launch.

Hot launch means the missiles own rocket motor is fired in the silo to move the missile out. The US has used hot launch for the majority of its ICBMs. Typically, the rocket exhaust enters a plenum chamber, and then the slightly cooler and lower pressure exhaust vents back up along the gap between the missile and the silo walls.

But a hot launch on a sub just won’t work. First, there’s no room for a plenum chamber. Second, if for some reason, the missile didn’t leave the tube, the rocket exhaust would very quickly melt through the steel of the tube, then the hull. And pretty soon, your sub would be a catastrophic loss.

So subs pretty much must use a cold launch. At the bottom of each missile tube is a large gas generator. This gas generator is like the industrial version of diet Coke and Mentos. A chemical reaction generates a large slug of highly pressurized gas almost instantly, much as a gas generator deploys the airbags in your car. This slug of gas pops the missile not only out of the tube, but also completely out of the water. Subs fire their missiles from periscope depth, which is about 32 feet. The missile gets about one missile length (44 feet) in the air before its rocket motor fires. And a D5 weighs about 65 tons. So it takes a fair amount of pressure to squirt on out of the tube. That’s a lot of diet Coke and Mentos.

Subs use high pressure air to launch from their torpedo tubes, as it takes a fair bit less pressure to simply push a torpedo out of the tube.

Our surface ships with the Mk41 Vertical Launch System use hot launch. That’s feasible because the rocket motors are much, much less energetic than a Trident missile. Each 8-cell section of a Mk41 shares a common plenum chamber and vents about the sides of the section. Several Russian surface ship missile systems use cold launch. One big reason why our surface ships use hot launch is because of the risk of a rocket motor not firing. Popping a 4ooo missile that consists mostly of rocket propellant and high explosives up into the air, only to have it fall back down on the deck would tend to give Safety Officers indigestion.

member_25400 · Post by **member_25400** » 10 Jun 2013 05:27

[quote="Austin"]
Launching an SLBM is a very complex exercise and the sub suddenly looses couple of tons even from single launch
...
The only time a SSBN ever launched its full salvo of SLBM was Delta 4 in 91 with 16 SLBM launches in under few minutes ...
[/quote="Austin"]

Good link. But I will posit that the mass launch of cruise missiles offers a similar challenge.
(href="http://en.wikipedia.org/wiki/BGM-109_Tomahawk#Operators")

member_23370 · Post by **member_23370** » 10 Jun 2013 21:58

Here is Indian Launch.courtesy Saya and DFI.

http://defenceforumindia.com/forum/stra ... post744953

ramana · Post by **ramana** » 25 Jun 2013 04:03

Any updates on the Arihant?

Must be quite complex fo it to take so long.

svinayak · Post by **svinayak** » 25 Jun 2013 08:52

Is it due to stealth features in Arihant?

Singha · Post by **Singha** » 25 Jun 2013 09:24

well we cannot expect tarmak type hourly updates on progress of reactor bringup.
when it sails out, I expect they will release a one liner.

wig · Post by **wig** » 29 Jul 2013 09:34

http://www.tribuneindia.com/2013/20130729/main5.htm

Nuclear-powered submarine Arihant all set to sail out from Vishakhapatnam

Indigenously built nuclear-powered submarine, INS Arihant, is finally set to sail out from its base at Vishakhapatnam. The 6,000-tonne submarine, armed with nuclear missiles, is ready after years of efforts interspersed with sanctions in 1998 and impediments due to non-availability of cutting-edge technology.

Arihant stats
• Cost: Rs 15,000 crore
• N-tipped missiles: 12
• Length: 110 m
• Breadth: 11 m
• Crew: 95
• Underwater speed: 24 knots (44 kmph)

“The nuclear reactor that will power the submarine can be formally declared ‘critical’ anytime now, while the nuclear-tipped missiles to be launched from underwater are in place,” sources said.

“Everything is ready,” a functionary said. “The wait is for the monsoon to subside before Arihant (slayer of enemies) dives into sea. A certain amount of calm is needed at sea when the vessel goes out the first time. The monsoon on the East Coast starts weakening by the middle of August, meaning the submarine will slither out in a couple of weeks from now,” he added.

“Around 95 per cent of harbour trials are over,” sources said. Once the submarine is out at sea, it will run on nuclear-powered 80MW pressurised water reactor (PWR). The PWR was developed by the Bhabha Atomic Research Centre (BARC) with assistance from a Russian designing team. It uses enriched uranium as fuel and light water as coolant and moderator.

Once at sea, the vessel will be gradually loaded with weapons and missiles. All parameters will be tested after each addition. “Each test will be conducted underwater for two months or more. This will include the Submarine Launched Ballistic Missile (SLBM)”, sources said.

New Delhi has done 10 underwater launches of SLBMs code named ‘B05’ using a submerged pontoon to mimic a submarine. It can travel 700 km, while the bigger variant, so far know as the ‘K-4’, can hit targets 3,500 km away and will finally be installed on Arihant and also the next two follow-on submarines of the same class.

The submarine will provide second-strike capability in case of a nuclear attack. It is the easiest to launch a nuclear strike from a submarine as it remains submerged, hence the enemy cannot detect it.

In December 2010, the then Navy Chief Admiral Nirmal Verma had announced: “When Arihant goes to sea, it will be on a deterrent patrol (armed with nuclear-tipped missiles).” Being nuclear-powered, the submarine will not have to surface for two months to breath, like the conventional vessels have to.

India will join the US, the UK, France, and China by having such technology and prowess.

Arihant has cost Rs 15,000 crore. It has been jointly developed by the Navy, BARC and the Defence Research and Development Organisation (DRDO) at the Visakhapatnam naval dockyard. Russian designers assisted in building the vessel. Other companies involved in the development of the submarine are Tata Power and Larsen & Toubro (L&T). The project, earlier known as the advanced technology vessel (ATV), has been under development since 1998.

tushar_m · Post by **tushar_m** » 29 Jul 2013 11:05

INS Arihant

Suraj · Post by **Suraj** » 29 Jul 2013 11:09

AoA! Finally for some pics of the thing beyond Gagan's best-effort drawings and assorted much more misleading article renders, MMS's wife breaking a coconut, and that solitary pic of the conning tower in the India Today article.

sum · Post by **sum** » 29 Jul 2013 12:23

^^ Wasn't this a really old S.Unnithan article from the time when Smt.Kaur was breaking a coconut on a black covered thingie in SBC?

nits · Post by **nits** » 29 Jul 2013 12:43

wig wrote:http://www.tribuneindia.com/2013/20130729/main5.htm

Nuclear-powered submarine Arihant all set to sail out from Vishakhapatnam

Indigenously built nuclear-powered submarine, INS Arihant, is finally set to sail out from its base at Vishakhapatnam. The 6,000-tonne submarine, armed with nuclear missiles, is ready after years of efforts interspersed with sanctions in 1998 and impediments due to non-availability of cutting-edge technology.

Busy Day for Satelites

Kartik · Post by **Kartik** » 29 Jul 2013 13:32

is that really what the Arihant will look like?

Singha · Post by **Singha** » 29 Jul 2013 14:09

per the single backlighted photo in public, the sail is conventional shape and has fins like in LA class subs.

abhik · Post by **abhik** » 29 Jul 2013 18:14

^^^
Also IIRC NDTVs Pallav Bagla show post launch has some official cutouts in the background.

member_20317 · Post by **member_20317** » 29 Jul 2013 18:53

sum wrote:^^ Wasn't this a really old S.Unnithan article from the time when Smt.Kaur was breaking a coconut on a black covered thingie in SBC?

Haan lekin khushi ka izhaar pehli baar hai.

When a nuke sub goes out is there any way to disrupt its signature using some decoy sound signatures?

member_23370 · Post by **member_23370** » 29 Jul 2013 22:35

Why would anyone announce with big fan fare when a nuke sub is going to go into ocean. It means it long gone on patrol.