SSK Diesel/Electric Sub Thread (AIP too)

FORBIN

Lieutenant General
Registered Member
Exact, the more fast SSK are Argentinians Type Tr 1700 a big customized Type 209.
25 kn, 2 in service, max 2200 t, big.

The submerged speed for almost all Diesel/Electrics, including AIPs is 20 knots max. Most surfaced speeds are 10-12 knots.
This includes the:
Type 212
Type 214
Yuan
Dolphin
Scorpion
Gotland
Kilo
S80
No Kilo or Lada annouced many times for him ! but nothing finaly.
And Dolphin II is AIP but no Dolphin, in general a AIP SSK is about 6/10 m more long for host a further tranche/compartment with the AIP system.

Normaly the 2 last Indians Scorpènes get an Indian AIP exist for this class MESMA AIP system use by Pakistani Agosta 90B.
SM AIP.JPG
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Brumby

Major
Move in AIP mode is mainly usefull for a SSK which patrol near of the coast in shallow water
in a defensive mission mainly and in this waters SSN are less comfortable the best AIP SSK can have a noise also low as the best SSN.

I also understand the recharge to the cells cannot be performed at sea and reason why it is best suited in the littorals for transit reasons. Nothing beats nuclear propulsion for speed and endurance. I think AIP is oversold considering its greater failure modes and higher vulnerabilities to implosives and explosives effects.
 

SamuraiBlue

Captain
I also understand the recharge to the cells cannot be performed at sea and reason why it is best suited in the littorals for transit reasons. Nothing beats nuclear propulsion for speed and endurance. I think AIP is oversold considering its greater failure modes and higher vulnerabilities to implosives and explosives effects.
Quite a lot of question concerning SSK, first off speed, yes they have top speed of 20+ knots under water the question is how much endurance they have at that speed. Basically if they snorkel they can maintain that speed for quite a long time but they will get easily spotted with a wake.

On batteries they can't do that fast especially lead acid batteries(although I hear this type has gone out for a long time). The reason is the power outage of batteries is limited so no the motors will not get enough electricity to drive them at full speed. The situation will improve with the advent with Li Ion batteries which has a higher electrical current outage but it still will not be able to reach top speed.

Noise, AIP is a lot quieter then nuke powered no matter how you measure it since nuclear subs requires a pump to cool the reactor and a steam/high pressure water turbine to generate the electric motor. No way are they going to escape noise from those two especially when going full speed.

Last re-charging the battery cells, they can do at sea although it takes a hell of a long time to do it and can only be done while snorkeling so most sub captains will avoid it as much as possible so not to be detected.

As I wrote above conventional batteries has a low outage but also has a low charging rate based on
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Fo
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Consider a battery that has been completely discharged (such as occurs when leaving the car lights on overnight, a current draw of about 6 amps). If it then is given a fast charge for only a few minutes, the battery plates charge only near the interface between the plates and the electrolyte. In this case the battery voltage might rise to a value near that of the charger voltage; this causes the charging current to decrease significantly. After a few hours this interface charge will spread to the volume of the electrode and electrolyte; this leads to an interface charge so low that it may be insufficient to start the car. As long as the charging voltage stays below the gassing voltage (about 14.4 volts in a normal lead–acid battery), battery damage is unlikely, and in time the battery should return to a nominally charged state.
The captain really does not really calculate this but the charger automatically reduces the amount in which the captain know how much time it takes to re-charge the batteries which is way too long.
Again with the advent of Li Ion batteries this situation had been improved.
 
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FORBIN

Lieutenant General
Registered Member
Noise, AIP is a lot quieter then nuke powered no matter how you measure it since nuclear subs requires a pump to cool the reactor and a steam/high pressure water turbine to generate the electric motor. No way are they going to escape noise from those two especially when going full speed.
Worck with speed in AIP mode, very low at more high speed good/quiet SSN take advantage.

Yes some says at very low speed the best AIP are more quiet as the best SSN because the noise of the pump but is no completely sure and the Nucl Subm are in general the most sophisticated.
Can depends reactor also seems the best are the reactor of the Seawolf which allow a max silent speed in fact operationnal speed of 25 kn, a 688i about 10 i think Virginia are a little less good as Seawolf but we are in the detail some DB with the more silent hunters killers never build.

Samurai pls what autonomy/speed for Stirling AIP on Soryu and same for the Harushio modified ?
 
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SamuraiBlue

Captain
Worck with speed in AIP mode, very low at more high speed good/quiet SSN take advantage.

Samurai pls what autonomy/speed for Stirling AIP on Soryu and same for the Harushio modified ?

As I said the SSN makes more noise no matter what speed they are at since their coolant pumps and steam/high pressure generators are always on-line. The AIP on the other hand whether it it be Stirling or fuel cell makes less noise where the Stirling engine runs no more then 30RPM due to it's chamber size.
The Soryu Stirling AIP only generates 300KW in total which equates to 400ps. The Soryu diesel engine power outage is around 8,000ps or 5 times the amount the Stirling is able to generate.
 

Jeff Head

General
Registered Member
You have give and take with the technology. There are pluses and minuses.

Nuclear can be very quiet...but it cannot be totally quiet because of the current mechanical processes required to keep it cool.

But it requires no refueling, is very fast, and for the high seas against surface ships and other SSNs, the US quieting technology is certainly tops.

An AIP sub can certainly be more quiet. The power available comes with virtually no noise.

But it is not a lot of power, so speeds are vastly reduced. This means it is very rest=tricted in how it goes about setting up an attack.

Generally, unless they lie in wait where they know the route a target military vessel is taking, or wait for it at a bottleneck, they have a hard time keeping up with any other military vessel. when using AIP.

Now, they might use their diesels to get in position...but when they do, they are much more loud then when operating under AIP.

So, as I say, they have their positive points and their negative points.
 

aksha

Captain
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If the hostile entry of United States Navy 7th fleet in the crucial stage of the 1971 war for the liberation of Bangladesh sent a shiver down the spine of Indian military commanders, events of last month gave them some relief. Not surprisingly there is a spring in the stride of those from India's beleaguered submarine arm at the Vishakhapatnam-based Eastern Naval Command (ENC). "It is among the coolest things to happen in recent times," said a young officer.

An operation under the high profile naval exercise MALABAR, between the navies of India, USA and Japan, featured a simulated battle to hunt and destroy each other's submarines. Locked in this match were two prowlers, the INS Sindhudhvaj (S56), a Soviet-designed EKM class of conventional submarine and the USS City of Corpus Christi (SSN705), a nuclear-powered attack submarine .The crew of both the vessels were asked to hunt the other down in a general area of the Bay of Bengal, based on 'available int'. They, subsequently dived.

Hours later, as they still searched the Americans were informed that the game was over already.

Unknown, they had been marked, tailed and suitably 'annihilated' by the 533mm torpedos 'fired' by their Indian counterparts from on board the INS Sindhudhvaj. What came as a clincher to the Indian side was the tool which detected the USS Corpus Christi - the 'made in India' Ushus SONAR (Sound Navigation and Ranging) which was recently installed. "The way it happens is that the Sindhudhvaj recorded the Hydrophonic Effect (HE) - simply put, underwater noise - of the nuclear powered submarine and managed to positively identify it before locking on to it. Being an exercise what did not happen was the firing," explained a naval officer. The HE thus captured can easily slide into the elaborate database that the any navy maintains for classifying and identifying foreign submarines. A US embassy spokesperson said, "We have no information on the results to share."

What will lend succour to the navy's submarine fleet is yet another validation of the kill potential of its premier platform. India has nine such submarines apart from four German-designed Shishumar class submarines. After years of disallowing its presence in any naval exercise involving foreign navies - attributed to the IN's desire to not its HE be recorded by a foreign player - this edition of MALABAR was the first time the Indian Navy (IN) allowed an EKM to take part.

Scoring over a US submarine also underscores the reputation that precedes an EKM submarine. Not without reason do the western navies term them 'black holes in the ocean' - a measure of how difficult it is to detect once submerged.

The six-day MALABAR exercise began on October 14 and saw the sea-going phase begin from October 16. Underwater warfare was among the most important aspects of this exercise.
Veteran submariner, Vice Admiral KN Sushil (retd), said, "I would have been upset had we failed at achieving what we did. A nuclear powered submarine always makes more noise vis a vis a conventional one and thus the results do not surprise me."

generally the Indian Navy deploys only its HDW's for training exercise with western navies ,
this is the first time they they deployed it in MALABAR

one must remember thet the the KILO was operating off its homeport and knew the waters and accoustic conditions better

but it is good news for India's beleagured submarine arm, that the old kilos can still hold its own .
 

aksha

Captain
KILO class
on The Sindhukirti's upgrade
and the indegenous USHUS sonar

What the Indian commander does have on his side is deep knowledge of the conditions of the Bay of Bengal. The Sindhudhwaj, based in Visakhapatnam, regularly operates in these waters and her commanding officer would look to take advantage of the salinity, variable temperatures and current patterns of these waters which often make submarine detection extremely challenging.

He also has a superb Indian designed and manufactured sonar system at his disposal recently fitted on his upgraded submarine. In June this year, the crew of the Sindhudhwaj, using their USHUS sonar, had with great accuracy, locked on to signals from the emergency locator beacon of a Coast Guard Dornier that had crashed. Search aircraft and other ships had picked up sporadic pings but were unable to pinpoint the specific crash site in the Bay of Bengal.
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However, inside the double-hull stealth submarine, its 53-member crew sported a confident look. “She is as good as any new, trust me,” assured a young officer. The Sindhukirti was commissioned into the Indian Navy on January 4, 1990. Today, she boasts of capabilities she’s never had. Where she could earlier fire only underwater torpedos with a range of under 20km, today she can fire about 18 missiles which can travel up to 300km to neutralise targets at sea and on shore. An old Soviet-designed sonar has given way to an indigenous one, the Ushus whose reliability the crew swears by. From analog readings in her control room, the crew gleans data off digital sets. Earlier, after having dived in, the submarine had to come to periscope depth (9m below the surface) to pick up direction or messages from the command centres ashore. This would put them in a vulnerable state. Now, all she has to do is to let out the 600m long chord of the Towed Wired Antenna (TWA) and receive communication as she prowls the depths of her choice.
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