[raghubhaskar]

Faboulous read, excellent narration. Thank a lot for this..!! I've seen a few movies (Down Periscope, U571, Crimson Tide, Hunt for the Red October) that are submarine based and has always wondered what life would be abroad one.

Some of your articles on sound refraction is really good. Knowing that a navy officer would need knowledge on geography, physics, ocean currents and what-not to be a good submariner is absolutely amazing.

Thanks once again for this excellent write up!

[peterjim13]

Originally Posted by V.Narayan

And finally lest we forget...

Here is what I have prepared myself with, though I have read multiple newspapers and articles on the same. I would request you to add a few things to help us understand a bit better on the submarine tech.

1. Could you tell us what exactly happened with INS Sindhurakshak. Isnt a ship berth - probably the safest place for a submarine to be.

2. Added to the above, could you tell me the usual pain and maintenance routines that are executed on the submarines. I am sure this would land upon the captain though. (to avoid disaster and calamities, I have heard the defence minister requesting the officers to be a bit careful in handling such assets, are our officers careless ? )

3. I have learned that Sindhurakshak was rescued with the help of an American Submarine rescue organization. Doesn't Indian Navy have any tech here. Why is the process so expensive. On top of all, why do we salvage such a ship ? Can we refurbish and use them, or is it going to be scrapped.

(* Thanks for your hint sir, owe those questions to you).

I know I am free to be stupid here, but let me ask this question too.

4. If we abandon a ship, it will float on the water and might bank on some shores; or may eventually sink.
What if we abandon a submarine in the middle of the ocean ?
Sinking is natural to it. Will it stay afloat?
Or what if the crew abandon it underwater while it is on the free flow ?

Thanks in advance sir. Please drop in an inbox message if my questions are not worth for a discussion amidst this forum !

[V.Narayan]

Originally Posted by peterjim13

1. Could you tell us what exactly happened with INS Sindhurakshak.

2. Added to the above, could you tell me the usual pain and maintenance routines that are executed on the submarines.

3. I have learned that Sindhurakshak was rescued with the help of an American Submarine rescue organization. Doesn't Indian Navy have any tech here.

...... but let me ask this question too.

4. If we abandon a ship, it will float on the water and might bank on some shores; or may eventually sink.
What if we abandon a submarine in the middle of the ocean ?
Sinking is natural to it. Will it stay afloat?
Or what if the crew abandon it underwater while it is on the free flow ?

Peterjim, thank you for your questions. I will try and answer them as best as I can as an amateur enthusiast. All questions are always welcome; no question is ever stupid. It keeps me occupied!

(1) On the basis of reports on the investigation that have been made public in the press the eventual cause of the explosion was one or more of the torpedoes exploding due to a fire. What the pieces made public do not cover is the cause of the fire. In my personal opinion one possible cause could be hydrogen gas building up due to old and worn out batteries that the bureaucracy was allegedly not permitting replacements off. At the time there were reports of old batteries which had not been replaced because the mandarins of the Ministry of Defence had been sitting on the files for years. For 45 years the Navy has been sourcing batteries from locally manufactured Standard Batteries (now Exide) and it has worked perfectly. A new manufacturer sued the Navy for not buying batteries from them. So instead of taking a stand the MoD decided to stop all battery purchases till this was sorted out -the typical bureaucrat approach of take no decision and don't let anyone take one either. So while the commanding officer was court martialed and the Naval Chief resigned out of a sense of honour nothing happened to the worthies who sat on files. Some error of inadequate precaution by the crew on board could also have been a cause but we will never know as no one inside survived.

(2) Submarines require periodic maintenance like ships. Key difference is that once in 5 to 6 years or thereabouts the pressure hull is checked by x-rays for microscopic cracks which could later rupture under intense water pressure.

(3) To salvage a sunken vessel is a very specialized and skilled task. There are a few companies across the world that do this and it is usual to bring one of them in to do the job. Even the Russians had to invite a consortium of Dutch and American companies to raise the Kursk. The raising of a sunken vessel, in this case ~2500 to 3000 tonnes, is done with giant floating cranes and pontoons attached to the sunken sub and then filled with air giving the whole piece buoyancy. The primary reason to salvage is to examine what happened and learn what we can of how to avoid future mishaps. The sub is too far gone to be re-used. It will probably be laid on the sea bed to use for diver training or become a target for torpedo practise.

(4) If we abandon a sub in the middle of the ocean on the surface with all hatches sealed it will float for a long time like a ship. It we abandon it underwater (assuming this can be done while keeping the interiors dry - suggest you don't try it!) with neutral buoyancy it will stay hanging underwater till it reaches a patch of water with lower density (due to variation in salinity or temperature) and will then start to gradually sink.

[Sutripta]

Originally Posted by V.Narayan

(4) If we abandon a sub in the middle of the ocean on the surface with all hatches sealed it will float for a long time like a ship. It we abandon it underwater (assuming this can be done while keeping the interiors dry - suggest you don't try it!) with neutral buoyancy it will stay hanging underwater till it reaches a patch of water with lower density (due to variation in salinity or temperature) and will then start to gradually sink.

Equally likely to float up, isn't it?

with neutral buoyancy it will stay hanging underwater

is what I have a problem with. A timeline needs to be established!

Regards
Sutripta

[Jeroen]

Originally Posted by Sutripta

Equally likely to float up, isn't it?





is what I have a problem with. A timeline needs to be established!



Regards

Sutripta

Its all down or up, pardon the pun, to Archimedes

[Sandman689]

Originally Posted by V.Narayan

Sandman, what goes up comes down. But unfortunately for submariners what goes down does not automatically come up! The math is in the buoyancy ratio. Russian subs typically have a buoyancy ratio of 25% to 33%. Which is to say if the pressure hull (in which the crew lives and works) displaces 1000 tonnes of water then the ballast tanks attached to it will displace 250 to 330 tonnes of water. Further in Russian subs the ballast tanks are placed centre, fore and aft adding to the safety. Western subs in a quest to reduce weight (amongst other reasons) have a buoyancy ratio of typically 15% with ballast tanks only fore and aft. This leaves less room from for an emergency.

Could you please clarify in this Math? Does buoyancy ratio of 25% mean that 25% of the sub's mass will be above water?And in this example, what is the net mass of the sub?

Also, on what parameters/factors does a sub's maximum safe diving depth depend on?

[V.Narayan]

Originally Posted by Sandman689

Could you please clarify in this Math? Does buoyancy ratio of 25% mean that 25% of the sub's mass will be above water?And in this example, what is the net mass of the sub?

Also, on what parameters/factors does a sub's maximum safe diving depth depend on?

(1) To best of my knowledge if a sub has a pressure hull that displaces 1000 cubic metres and ballast tanks that displace 250 cubic metres it is said to have a buoyancy reserve of 25%. When submerged its displacement will be 1250 cubic metres and when surfaced 1000 cubic metres. So, yes, on the surface 25% of the pressure hull is above the water. The fin or conning tower is never a part of the pressure hull. So the volume of the conning tower is an added visual piece above the 25%. Not sure what the question on net mass is. Hope this helps.

(2) Maximum safe depth is largely a function of the composition and thickness of the steel alloy from which the pressure hull is built, the quality and accuracy of the welding and its ' perfect roundness'. It is not as if you can just make the steel thicker - the thickness and pressure bearing quality of the alloy need to go hand in hand. However once you get below 600 metres in depth the water pressure is so great that a lot of the equipment that otherwise functions in the open water (sonars, compressed air bottles, anchor equipment, waste discharge systems etc) start facing difficulties in functioning. At 600 metres down the pressure is 600 tonnes per square metre. The Russians built a few semi-experimental hulls out of titanium which is immensely difficult to weld. One of them named 'Mike' class by NATO was said to have a normal operational depth of 1000 metres and a design depth of 1250 metres.

World Submarine Fleets

For interest of all readers this is a compilation of today's major submarine fleets by quality and size. I have ignored North Korea due to the bulk of their fleet being of 1950s vintage design albeit of recent construction.

USA

14 SSBN ballistic missile nuclear powered submarines
4 SSGN guided missile submarines
57 SSN attack submarines, nuclear powered

China - People's Liberation Army, Navy

5 SSBN ballistic missile nuclear powered submarines
5 SSN attack submarines, nuclear powered
40 SSK diesel electric powered attack submarines (also referred to as hunter killers)
17 SS diesel electric powered patrol submarines ie without submarine to submarine attack capability

In size China is now rapidly getting to be the equal of Russia. I have placed them above Russia as it is difficult to judge the maintenance and availability of the fleet in Russia now

Russia

13 SSBN ballistic missile nuclear powered submarines
7 SSGN guided missile submarines
18 SSN attack submarines, nuclear powered
21 SSK diesel electric powered attack submarines (also referred to as hunter killers)

UK

4 SSBN ballistic missile nuclear powered submarines
7 SSN attack submarines, nuclear powered

France

4 SSBN ballistic missile nuclear powered submarines
6 SSN attack submarines, nuclear powered

UK and France maintain small fleets of very modern nuclear powered boats only including 4 ballistic missile armed ones. This helps them stay in the league tables and count in the UN Security Council

Japan

17 SSK diesel electric powered attack submarines (also referred to as hunter killers)

Japan's fleet of diesel electric hunter killers are the best of their kind in the world as would be expected from such a technologically advanced nation

India

1 SSBN ballistic missile nuclear powered submarines under trials
1 SSN attack submarines, nuclear powered
13 SSK diesel electric powered attack submarines (also referred to as hunter killers)

If our myopic thinking had not stopped the Type 1500 programme in the mid-1990s we would have been far better placed today. INS Kalvari, built to the French Scorpene design, is expected to join the fleet later in 2016. Photo below shows the boat being moved out for trials.

South Korea

13 or 14 SSK diesel electric powered attack submarines (also referred to as hunter killers)

Turkey

13 SSK diesel electric powered attack submarines (also referred to as hunter killers)

Turkey and South Korea entered the club of submarine builders at the same time as us ie in the 1980s and with the same designer-manufacturer combination ie IKL-HDW of Germany. But they stayed the path with long term strategic thinking and have in these 30 years built 13 subs each with gradual improvements. It is a reflection of what could have been with us. We are effectively re-starting all over again with the Scorpene project now underway.

[V.Narayan]

India successfully tested a submerged launch of K-4 missile from INS Arihant on 30th March 2016 according to press reports. INS Arihant which is under trials is India's first ballistic missile armed, nuclear powered submarine. It has been designed and built in India. The K-4 missile is a part of the 'K' series being developed. The K standing for Kalam as a mark of respect to the late President APJ Kalam. Arihant is said to be capable of carrying 4 of the 3500 kms range K-4 or 12 of the smaller shorter range K-5 (range 700 kms). These tests bring India one more step closer to commissioning her own nuclear triad. To be successful INS Arihant needs to marry three areas of technology - the submarine hull with the nuclear propulsion and both together with the missile that needs to be launched from underwater. Of course the missile has to then find its way to the target. There will be a fourth leg and that will be command and communication by the political and military leadership of when to use and how to give a clear and concise instruction.

All in all the successful firing of a ballistic missile from a submerged submarine is a proud moment for India's scientists and Navy.

http://www.firstpost.com/india/nucle...AT_LATEST_NEWS
http://www.ibtimes.co.in/drdos-nucle...-report-673978

Photo shows the K-4 being launched from a submerged pontoon.

[Dieselritzer]

Narayan Sir, I cannot thank you enough for the depth of information that you have painstakingly compiled. I have a few questions, it might sound silly but with a non technical background, I am just curious to know more.

1. You mentioned that the the Diesel-Electric subs will be more quite than the Nuclear powered ones. So in a nuclear powered sub, it is the steam power that turns the prop, and this mechanism is more noisy compared to the pure electric motors that turn the prop in a DE sub, is my understanding correct?

2. Not related to subs, but the Brahmos has a range of 290 Kms, isn't this range to small? In this case we would have to keep these missiles ready to launch very close to our borders with our neighbors, right?

3. The submarines have a mother ship, are these mother ships specially modified to be able to work in syn with the Subs? Like a special hull design to let the sub stay very close to the ship? Or any warship can be used as a Submarines mother ship?

4. Does it ever happen that a submarine turns sides way when submerged? Like in the movie K-19 they show a scene where the Submarine is doing a rapid ascend and she starts to roll. Does it ever happen in real?

5. Not sure if you have answered this or written about this, but just curious, why is the a Submarine referred to as "She", "her" ? Just curious here.

Well, these are the questions as of now :-) The very first Submarine movie i saw was K-19 and it is still my favorite Submarine movie. What a story it is, the way it is filmed is just amazing and gives us a glimpse of how difficult those days of Cold War were for those young men and women.

It is my dream to see a submarine in water, i was once on a ferry boat in Mumbai and at a very far distant i saw a submarine, but it was too far, nevertheless i was thrilled. I'll go crazy if i ever see one very close. Are civilians ever given an opportunity to see a submarine? If yes, what is the process?

From this article, it was interesting to know about Germany who helped us so much, the help from Russia is in general known but Germany was a new information to me. Also, the double standards by the Yanks is yet again eminent.

When you wrote about the PNS Ghazi, that had to be one of the most interesting reads of my life and our armed forces are filled with so many unsung heroes. i feel that yes, giving your life for your country is the greatest sacrifice of all and it should be honored at the highest level, but at the same time, equal recognition should be given to people who took brave smart decisions and helped us retain a stronghold in those conditions.

Thank you once again Sir for all this information, it is indeed a proud feeling to go through our history and achievements.

Jai Hind

[V.Narayan]

Originally Posted by Dieselritzer

1. You mentioned that the the Diesel-Electric subs will be more quite than the Nuclear powered ones. So in a nuclear powered sub, it is the steam power that turns the prop, and this mechanism is more noisy compared to the pure electric motors that turn the prop in a DE sub, is my understanding correct?

2. Not related to subs, but the Brahmos has a range of 290 Kms, isn't this range to small? In this case we would have to keep these missiles ready to launch very close to our borders with our neighbors, right?

3. The submarines have a mother ship, are these mother ships specially modified to be able to work in syn with the Subs? Like a special hull design to let the sub stay very close to the ship? Or any warship can be used as a Submarines mother ship?

4. Does it ever happen that a submarine turns sides way when submerged? Like in the movie K-19 they show a scene where the Submarine is doing a rapid ascend and she starts to roll. Does it ever happen in real?

5. Not sure if you have answered this or written about this, but just curious, why is the a Submarine referred to as "She", "her" ? Just curious here.

Dear Dieselritzer, Thank you for reading and appreciating the photo essay. I am glad you enjoyed it. I am not an expert but I will attempt to answer your questions.

(1) Your understanding of nuclear subs' propulsion is right. The nuclear plant creates the heat that generates the steam that drives the turbines which in turn rotate the propeller through a multi-stage transmission unit. All these pieces require a lot of pumps, motors and ancillary equipment to run them which creates a lot of noise and the transmission unit putting through say 15,000 to 30,000 kilowatts is also noisy as hell. In contrast when running on its motor the diesel electric boat has just that one motor humming quietly. Further in patrol mode the diesel-electric would be loitering at say 4 knots (~7.5 kmph) consuming power measured in mere tens of kilowatts only. Further even if a nuke sub is cruising along at 4 knots the entire paraphernalia of a 30MW plant is running. Diesel Electric boats carry a small creep motor of less than ~ 100 kw in output which they use when patrolling slowly - in this case the main motor of say 300 kw is shut down. A small 10kw motor is easier to insulate than a 30MW nuclear-steam power plant. The nature of a smaller slow turning electric motor versus a nuclear plant, whose pumps have to keep running even if the sub is stationery, leads to a very significant difference in noise levels.

(2) Brahmos is an Indo-Russian project. The missile technology control treaty does not permit a country (Russia here) to sell missiles to another or develop missiles for another country (in this case India) that does not have that specific technology if the missile has a range in excess of 300 kms. Hence Brahmos has a design range of 290 kms. For a ship to ship engagement that is a significantly long range - long enough for acquisition and identification to start becoming a challenge. For land attack some may consider it on the shorter side but it is more than good enough. Our attack on Karachi harbour using missile boats in December 1971 used a version of the Styx missile with a range of ~45 kms and the attack was a resounding success.

(3) Mother ships are used to enable subs to operate far from their usual bases. A mother ship provides support at a distant anchorage. Normally speaking subs can operate quite well without a mother ship. It is a 'good to have' and not a 'need to have'. Submarine mother ships (less usual today than 50 years ago) are tailored made for the task.

(4) Less likely in real life. But yes a submarine like a ship can roll quite a bit - say 35 degrees very comfortably either way. A sub I guess would be hard pressed to capsize underwater unless she damages her ballast tanks. Modern tear drop shaped subs can be flown underwater like an aircraft. So when they turn sharply at speed the hull will roll like an aircraft does when banking. A sub would roll like K-19 if it is not being able to control its balance through its trim tanks. (PS I haven't seen the movie)

(5) Ships in the English language carry the feminine gender and in the Russian language the masculine gender. The English reference of a ship (or a submarine) as a she has its origins in the Latin language. For sailors at sea for long periods the ship is the mother. all aircraft carrier pilots refer to their ships as 'mother'….protector, nourisher, safety et al. Think of Motherland.
If you want some saucy answers read the first two reasons on the link here http://www.glossophilia.org/?p=1411

Best wishes, Narayan

[Jeroen]

Originally Posted by V.Narayan

Dear Dieselritzer, Thank you for reading and appreciating the photo essay. I am glad you enjoyed it. I am not an expert but I will attempt to answer your questions.

(1) Your understanding of nuclear subs' propulsion is right. The nuclear plant creates the heat that generates the steam that drives the turbines which in turn rotate the propeller through a multi-stage transmission unit. All these pieces require a lot of pumps, motors and ancillary equipment to run them which creates a lot of noise and the transmission unit putting through say 15,000 to 30,000 kilowatts is also noisy as hell. In contrast when running on its motor the diesel electric boat has just that one motor humming quietly. Further in patrol mode the diesel-electric would be loitering at say 4 knots (~7.5 kmph) consuming power measured in mere tens of kilowatts only. Further even if a nuke sub is cruising along at 4 knots the entire paraphernalia of a 30MW plant is running. Diesel Electric boats carry a small creep motor of less than ~ 100 kw in output which they use when patrolling slowly - in this case the main motor of say 300 kw is shut down. A small 10kw motor is easier to insulate than a 30MW nuclear-steam power plant. The nature of a smaller slow turning electric motor versus a nuclear plant, whose pumps have to keep running even if the sub is stationery, leads to a very significant difference in noise levels.

n

I'm not sure that is correct. To my understanding when a nuclear sub runs silent, ie slow speeds, the steam system works largely on natural convection principles. The only pump running is the cooling pump.

The main noise are coming from the steam running through the pipes, expanding in the turbine etc.

Also, I don't think the steam produced by nuclear reactor drives the turbine directly. That means you would have highly radioactive steam going through the turbine, pumps and condensor. The steam heated by the reactor is fed through a steam generator. That is often called the secondary circuit and that is the steam that drives the steam turbine.

Here is a good explanation with some easy to understand diagrams

http://fas.org/man/dod-101/sys/ship/eng/reactor.html

As fas I know American and Russian nuclear subs have steam turbine driving the propellor. French nuclear subs have the steam turbine drive a generator that ultimately drives an electric motor.

Jeroen

[V.Narayan]

Originally Posted by Jeroen

Also, I don't think the steam produced by nuclear reactor drives the turbine directly. That means you would have highly radioactive steam going through the turbine, pumps and condensor. The steam heated by the reactor is fed through a steam generator. That is often called the secondary circuit and that is the steam that drives the steam turbine.

In the post above I am only answering his question on why nuclear submarines are noisier than diesel electric ones. The explanation on primary circuit and secondary circuit has already been explained in post #1 in summary.

[Jeroen]

Originally Posted by V.Narayan

In the post above I am only answering his question on why nuclear submarines are noisier than diesel electric ones. The explanation on primary circuit and secondary circuit has already been explained in post #1 in summary.

Its still incorrect I believe. The noise is mostly from the steam as there is very little mechanical noise, contrary what you wrote.

I have never sailed on nuclear powered vessels. But I am a certified Dutch Marine Chief Engineer with an unlimited ticket. Under Dutch maritime law there is no distinction between diesel, steam, electric or even nuclear propulsion. Remarkably enough.

So during my naval college days we had to learn a lot about nuclear systems. Never had the pleasure of putting it into practice though.

I have had the pleasure to be on an exchange program with the US Navy in the early eighties and I spend a couple of days on the Nuclear carrier Enterprise. We were authorized to visit the nuclear part of the engine room as well. (After signing waivers and NDA)

Would love to spend some time on a (nuclear) sub! Bit difficult these days.

[Ameya Janvekar]

I think the noise component of nuc boats, alongwith the expansion & passage of steam, is also of the pumps which are used to circulate the coolant in the reactor unit.

Had read somewhere that to minimise this noise & harmonic during close quarter manuvers, newer design reactors use a coolant system when during low power setting, the coolant circulates naturally ( forgot the actual tech name for this phenomenon ).

Also if I am not wrong, these pumps etc need to be mounted on mounts / isolators / dampers to prevent the transmission of the same to the hull.

Even if the sub is purely drifting, the reactor coolant pumps will be running & this will always make a minimum noise whereas for a Diesel-Electric sub, once the motor is stopped, there will be no mechanical hamonics / vibrations etc.

Would recommend if possible & if you enjoy the topic of subs, to read a superb novel titled THE HUNT FOR RED OCTOBER by Tom Clancy. It has superb detailing as for the equipment, tactic etc used by & againt subs. Yes the technology & tactics have since evolved, but a gripping tale till the end.

[Gansan]

Originally Posted by V.Narayan

Viola. Now this is an extraordinarily ordinary question. In the Indian Navy all personnel are self insured through a group scheme the Navy runs internally. So the insurance companies are out of it. I do not know how the mechanics run but this being an internal scheme I don't think submariners are asked to pay a higher premium

I think the same holds good for IAF Pilots as well. The brother of a colleague of mine was in the Airforce (not a pilot though) when the Lt.Nachiketa incident took place during the kargil war, and I remember him saying they have to contribute quite a significant part of their pay towards premium.