INS Vikrant: News and Discussion

Gurinder P · Post by **Gurinder P** » 12 Aug 2013 11:05

SaiK wrote:yup.. what prevents us to house an ASW sonar on a bow?

The usefulness of the sonar, if the ship is traveling at higher speeds. Bow Sonars degrade in scanning, with higher wakes and turbulence that is caused when ships travel at a higher speed. Corvettes, Frigates and Destroyers are the best ships for ASW, since they can sprint to the sub, and they have towed sonars, that are more effective since they are at a distance from the ships wake/turbulence.

However, I am surprised over the lack of a bulbous bow, since it usually gives bigger ship less drag, thus allowing greater speeds and fuel efficiency.

keshavchandra · Post by **keshavchandra** » 12 Aug 2013 11:25

When the ceremoney will start? DD or NDTV will do the the live telecast? Any update.

member_23455 · Post by **member_23455** » 12 Aug 2013 11:46

It's done...twitter is your best friend, for now.

vina · Post by **vina** » 12 Aug 2013 11:51

Hmm. Saw the ceremony on TV. A small pooja with two priests conducting, Elizabeth Anthony applied Tilak and broke a coconut and it was done.

Nice and very Sekoolar onlee. The ship looks good. Now they should start work on a 60,000 T class with Cats. 60K tons is about the outer limit you can have with conventionally oil powered stuff with acceptable range and endurance .

I do hope that the IN looks at cogenerated steam via waste heat recovery from from the GT exhausts (~~each~~ 4 * LM2500 puts out something like 88 120 MW, so that means roughly ~~2*88~~ 260 MW goes out via the smokestacks .. that is quite a bit of energy being let out!) to put steam into cats and also go CODLAG in the next ship.

Singha · Post by **Singha** » 12 Aug 2013 11:56

65K empty the QE2/PA2 size is definitely a sweet spot in cost x airwing x power equation IFF one can get in on CATS.
gets those CATS and hawkeye to justify the $5b price tag.
beyond that it gets into dodge durango with XL tyres category...bigger and badder just because you can afford it..khan style.

a fleet of 3 X PA2 carriers with 32knot top speed + SSNs will strike fear into the IOR rim for sure.

----

the JFK was the biggest and last conventionally powered supercarrier in the us navy. her dimensions indicate she was every bit a supercarrier
Displacement: 60,728 tons light , 82,655 tons full load
Length: 1,052 ft (321 m) overall
Beam: 252 ft (77 m) extreme => note the massive width typical of a supercarrier

she carried 80 aircraft.

power plant was a huge steam turbine setup it seems:
8 Babcock and Wilcox boilers 1200 PSI, 4 steam turbines, 4 shafts, 280,000 shp (210 MW)

I dunno about LM2500 vs steam turbine normal operating power but on paper, even the puny ADS is having more installed power than a ship 50% bigger its size with 2X its airwing.

vina · Post by **vina** » 12 Aug 2013 12:11

Singha wrote:the JFK was the biggest and last conventionally powered supercarrier in the us navy. her dimensions indicate she was every bit a supercarrier
Displacement: 60,728 tons light , 82,655 tons full load
Length: 1,052 ft (321 m) overall
Beam: 252 ft (77 m) extreme => note the massive width typical of a supercarrier

she carried 80 aircraft.

power plant was a huge steam turbine setup it seems:
8 Babcock and Wilcox boilers 1200 PSI, 4 steam turbines, 4 shafts, 280,000 shp (210 MW)

I dunno about LM2500 vs steam turbine normal operating power but on paper, even the puny ADS is having more installed power than a ship 50% bigger its size with 2X its airwing.

The trick here is that as the displacement increases the powering and hence fuel consumption per TON of displacement DECREASES for a given speed. Hence the reason why it is efficient to go for large cargo ships (think VLCC) and same for airplanes (think A380 and 747s etc) . So, yes, if you go from 30K ton displacement to say 90K ton like Unkil, you will not need 3X the power of 30K ton for a speed of say 32K but significantly less proportionally (say 2X in power).

Philip · Post by **Philip** » 12 Aug 2013 12:34

Nothing.In fact many carrier designs do have bulbous bows.There are some conditions though.The Italain Garibaldi class light carrier has a bow-mounted sonar.However,one is sure that the IN's design team have done their hydrodynamic model testing earlier and have settled for the best hull configuration.

Wik.

The bulb modifies the way the water flows around the hull, reducing drag and thus increasing speed, range, fuel efficiency, and stability. Large ships with bulbous bows generally have a twelve to fifteen percent better fuel efficiency than similar vessels without them.[1] A bulbous bow also increases the buoyancy of the forward part and hence reduces the pitching of the ship to some small degree.

Bulbous bows have been found to be most effective when used on vessels that meet the following conditions:

the waterline length is longer than about 15 metres (49 ft)
the vessel will operate most of the time at or near its maximum speed [2]

PS:Reg AEW,the emergence of carrier UCAV/UAVs has sparked interest in developing long endurance multi-mission versions for carrier ops.As many as 5 to be in ops at one time are being examined.They will perhaps replace manned AEW systems like Hawkeye as they can stay aloft far longer.We are on the cusp of an RMA with the advent of carrier unmanned aircraft.Within a decade we will see carriers having part of their air group consisting of multi-mission UCAVs.If made large enough to carry Harpoon/Exocet air-launched anti-ship missiles within an internal weapons bay,or underwing,an immediate prosecution of an enemy contact may be carrried out,instead of the AEW aircraft/helos transmitting the contact details to the carrier task force or airborne aircraft using NCW,for other naval assets to attack,saving time.

Singha · Post by **Singha** » 12 Aug 2013 13:20

one adv of 90K behemoth is likely ability to mount 4 cats, which provides more redundancy and a higher sorties rate as a/c are fetched from below and fed into them.
the CDG only has a paltry 2 catapults http://www.navair.navy.mil/lakehurst/nl ... /1213g.gif

khan, always wise in these matters I think has had 4 on every carrier since they crossed the 60k mark and moved into nuclear propulsion. khan carriers are meant to survive "a few hard blows" and not break and run like cowardly yindu and french carriers attacked by TSPAF.

Philip · Post by **Philip** » 12 Aug 2013 14:03

That's a very good point Singha,the number of cats.If the cats are damaged in an attack,or suffer from a tech problem,and the carrier cannot launch aircraft,she is a floating duck in the water.The second point is that with more cats,one can launch aircraft faster to deal with a crisis/contact before the enemy can attack you.With STOBAR,as long as the flight deck is undamaged,launches can take place.Carriers also have to launch into the wind with cats.

SaiK · Post by **SaiK** » 12 Aug 2013 18:23

Gurinder P wrote:
SaiK wrote:yup.. what prevents us to house an ASW sonar on a bow?
The usefulness of the sonar, if the ship is traveling at higher speeds. Bow Sonars degrade in scanning, with higher wakes and turbulence that is caused when ships travel at a higher speed. Corvettes, Frigates and Destroyers are the best ships for ASW, since they can sprint to the sub, and they have towed sonars, that are more effective since they are at a distance from the ships wake/turbulence.

However, I am surprised over the lack of a bulbous bow, since it usually gives bigger ship less drag, thus allowing greater speeds and fuel efficiency.

good points.. may be the bulbous might appear later.. is that a possibility? is that a normal process to fit it later on?

btw, for jsf-vtols, a dual cat should be more than enough right?

chaanakya · Post by **chaanakya** » 12 Aug 2013 18:36

JTull wrote:chanaaka, it is unlikely that satellite image is from march as I think IAC moved back into dry dock around dec-12.

Bade, that's a great picture. I was wondering how can they "launch" such a massive ship when last time they floated it out to make way for INS Viraat.

JTall , that image is taken by DigitalGlobe and datemarked 11.2.2013 in Google Earth. The one in Dock is INS Viraat undergoing retrofit at CSL while INS Vikrant was being moved to Dry Dock. I checked up with timeline images in google earth. It checks out. Viraat was due to rejoin Navy by July End.

member_23455 · Post by **member_23455** » 12 Aug 2013 18:47

SaiK wrote:btw, for jsf-vtols, a dual cat should be more than enough right?

While vertical landings are par for the course for V/STOL "non-tailhook" aircraft, you really don't want to be doing vertical take-offs because of the massive range/payload penalties it puts on the aircraft.

There's a lot more we can do to improve our capability beyond the number of cats. Develop a true blue water CBG doctrine and train for it, and make all pilots in a squadron night capable - something only the US does as a gold standard.

SaiK · Post by **SaiK** » 12 Aug 2013 19:01

well, a ski-jump ramp may not be needed for jsf - short take off.. they can get the assisted lift with their vectored engine.

Mihir · Post by **Mihir** » 12 Aug 2013 19:14

The CdG has just two cats because she doesn't carry too many aircraft, and has just two deck elevators. Say you add four cats to a ship the size of the CdG/Vikrant. Will you be able to bring aircraft up to the deck fast enough to put them to good use? American supercarriers have more cats, but the also have four elevators and plenty of deck space to store the aircraft, unlike smaller carriers.

As far as damage in an attack goes, the catapults aren't the main concern. The first thing to go will be your deck elevators. Note how Khan's carriers have elevators on both sides of the ship; that's great from a damage mitigation standpoint. The CdG/Vikrant/Vikramaditya, with their narrow decks, have do make to with elevators on the same side. One missile hit, and they're both likely to be put out of action.

Another concern is deck strength. On a modern carrier, the deck is a part of the structure. Every slot and cut-out severely weakens it. That too limits the number of cats and elevators one can install.

SaiK · Post by **SaiK** » 12 Aug 2013 19:21

yes.. USN gold standards and capabilities driven model is something most nations will chase after.. it an expensive affair as well, but it takes you faster to the blue water... with some initial hiccups like in most capable platforms that matured.

member_23455 · Post by **member_23455** » 12 Aug 2013 19:27

http://photogallery.indiatimes.com/news ... 775650.cms

SaiK · Post by **SaiK** » 12 Aug 2013 19:40

^^ from the source:

what are those stains on the ski-jump?

member_23455 · Post by **member_23455** » 12 Aug 2013 19:50

http://www.livefistdefence.com/2013/08/ ... rrier.html

Over 80% of the structure, containing about 2300 compartments has been fabricated, over 75% has been erected, all the major machinery, such as the two LM2500 Gas Turbines developing a total power of 80 MW, the diesel alternators capable of producing about 24 MW and the main gear box have been fitted.

Seems the MoD can't get any press release right these days...

member_20067 · Post by **member_20067** » 12 Aug 2013 20:05

Why does press always mention that only US, Britain, France and Russia can build Aircraft Carriers..? Japan can build a world class carrier any day ... they just don't do it based on treaties post WW2. South Korea, Denmark and Sweden also have great ship building capabilities and can easily build the hull. The integration, electronics etc. are different matter though

Singha · Post by **Singha** » 12 Aug 2013 20:24

Italy and spain too. So can germany if they really need to.

SaiK · Post by **SaiK** » 12 Aug 2013 20:34

when has press spoken correct?

member_20067 · Post by **member_20067** » 12 Aug 2013 20:50

Will the island be constructed separately like below?

Katare · Post by **Katare** » 12 Aug 2013 20:56

No one's bitching about it means we have got excellent built quality! Smooth with sharp and stealthy lines! Great job!

The shipyard looks clean and well organized as compared to slumish look of Mumbai/Kolkata yards!

member_20067 · Post by **member_20067** » 12 Aug 2013 21:11

Alternate view

Suraj · Post by **Suraj** » 12 Aug 2013 21:29

Another image that I haven't seen posted here yet:

Both the section that mounts the island + twin elevators (slots visible) on the visible side, and the angled deck on the other side, remain to be attached.

Elsewhere, I've seen pictures of the bridge section lying on the ground at CSL, so it looks like the fabrication of these two sections is at least partially done too.

I can't speak for why they didn't install those before the launch. Perhaps design choices warranted launch readiness now, or GoI leaned on them to launch in time for I-day, since there'll probably be elections before the next one.

The build quality does look quite good, as Katare said.

John · Post by **John** » 12 Aug 2013 21:32

Prithwiraj wrote:Why does press always mention that only US, Britain, France and Russia can build Aircraft Carriers..? Japan can build a world class carrier any day ... they just don't do it based on treaties post WW2. South Korea, Denmark and Sweden also have great ship building capabilities and can easily build the hull. The integration, electronics etc. are different matter though

Because those are only countries that have currently built carriers in modern era by your logic almost any developed or developing nation can build carrier if they infinite amount of funds to update their Shipyards. Only country i would add to that list is China, Italy, Spain, Korea and Japan.

SaiK · Post by **SaiK** » 12 Aug 2013 21:32

fantastic!

Sagar G · Post by **Sagar G** » 12 Aug 2013 21:37

Having the capability to do it and doing it are two different things. Japan possesses 5th gen sc alloys, where are their jet engines ??? Let's keep the self loathing for some other day.

member_20067 · Post by **member_20067** » 12 Aug 2013 21:41

Sagar G wrote:Having the capability to do it and doing it are two different things. Japan possesses 5th gen sc alloys, where are their jet engines ??? Let's keep the self loathing for some other day.

Japan is a special case --- their defense investment and political will was severely hampered by WW2 outcome

Sagar G · Post by **Sagar G** » 12 Aug 2013 21:48

Prithwiraj wrote:Japan is a special case --- their defense investment and political will was severely hampered by WW2 outcome

Whatever it's there choice, no need to bring in name of country's who can allegedly do the same feat as done by India. Sing songs for them when they do it no need to pooh pooh down INS Vikrant as if it is a small feat.

Aditya G · Post by **Aditya G** » 12 Aug 2013 21:55

What are the sponsons at either side front for? Ak-630?

http://4.bp.blogspot.com/-2l9cyl8vH_c/U ... 779942.jpg

The launch "t402" looks like navy/sagar prahari ball ... any idea of the model?

NRao · Post by **NRao** » 12 Aug 2013 22:03

SaiK · Post by **SaiK** » 12 Aug 2013 22:15

models here:
http://idp.justthe80.com/naval-projects ... project-71

Eric Leiderman · Post by **Eric Leiderman** » 12 Aug 2013 22:51

Suraj there are at least a couple of reasons that the island and other appendeges have not been welded on before she is floated out of the graving dock

1) you will see spoonsoons attached to the hull, that means that there is a restriction on the vessels draft which the sponsoon s counteract with their extra buoyancy, so less the superstructure less the requirement for buoyancy.
2) from a shipeyard real estate point of view , it is much more costly to keep a vessel in a dry dock than alongside a quay.
vessel's hull is now water tight and the remaining work can be done with her afloat at a cheaper berth.
3) the dry dock can be used for other ships.

titash · Post by **titash** » 12 Aug 2013 23:06

Prithwiraj wrote:Japan is a special case --- their defense investment and political will was severely hampered by WW2 outcome

Prithwiraj-ji, everyone has their reasons why they couldn't do it.

The British could, but wouldn't because they would rather fund the arts and the royal weddings instead
The Japanese and Germans could, but wouldn't because they were beaten to a pulp in WWII, and have pacifist (sic) leanings now
The Aussies could, but wouldn't because they can't find enough trained crews to run those ships
The Italians and Spanish could too, but until quite recently I heard talk about their economies running down and unemployment rate being super high

The Indians today have the technical ability, financial resources, and political will to do it. Enough said.

SagarAg · Post by **SagarAg** » 12 Aug 2013 23:09

This angle gives a view of its mammoth size

Bade · Post by **Bade** » 12 Aug 2013 23:24

double post

Bade · Post by **Bade** » 12 Aug 2013 23:25

ABP news link posted above gives a good idea of the size as it pans the IAC's entire length.

One of the Navy personnel was quoted as saying it is like 4 acres on deck, and there are 10 stories in total.

Kersi D · Post by **Kersi D** » 12 Aug 2013 23:26

titash wrote:
Prithwiraj wrote:Japan is a special case --- their defense investment and political will was severely hampered by WW2 outcome
Prithwiraj-ji, everyone has their reasons why they couldn't do it.

The British could, but wouldn't because they would rather fund the arts and the royal weddings instead
The Japanese and Germans could, but wouldn't because they were beaten to a pulp in WWII, and have pacifist (sic) leanings now
The Aussies could, but wouldn't because they can't find enough trained crews to run those ships
The Italians and Spanish could too, but until quite recently I heard talk about their economies running down and unemployment rate being super high

The Indians today have the technical ability, financial resources, and political will to do it. Enough said.

Well said.

srin · Post by **srin** » 12 Aug 2013 23:27

SaiK wrote:models here:
http://idp.justthe80.com/naval-projects ... project-71

Interesting ... the take-off guide lines intersect with the angled-deck. Does that mean that concurrent take-offs and landings aren't possible ?