Hunting a SSK

[RubiconNZ]

I've seen some comments on the net the Dutch Walrus Class is also able to dive 600+m, the Italian wiki site about the class mentions 620m max diving depth. But I've also seen some other (higher) figures for the max depth.

Oh nice, didn't see that one,
Cheers

 

[submerged]

official diving depth of the walrus-class submarines is +200 metres, anything else is pure speculations, as well as most things discussed here about submarines i'm affraid.. As a submariner i can guess wich subs equal or pass the 214's diving depth but ofcourse that would also be pure speculations

 

[Falstaff]

I've seen some comments on the net the Dutch Walrus Class is also able to dive 600+m, the Italian wiki site about the class mentions 620m max diving depth. But I've also seen some other (higher) figures for the max depth.

Perhaps you're confusing max operating depth which includes a certain confidence coeeficient and max diving depth? I'm not sure about the english term for it, in German it's "Zerstörungstiefe" and means the theoretically achievable depth based on calculations.

For example the WW-2 class VII and IX boats had a much greater max diving depth than imagined due to inaccurate calculation procedures, which saved a lot of German soldiers. On the other hand at least one type of smaller, coastal sub had an actual max diving depth lower than the max operational depth which led to losses once these boats were taken beyond their intended roles.

600 metres for the walrus seems to be a lot for a conventionally (steel-) built submarine...

It really is a shame gf won't tell which one it is... but given that in this forum the Aussie UDT is praised from time to time (and righteous so, I guess) by him I suspect it's the Collins...

 

[Grand Danois]

It really is a shame gf won't tell which one it is... but given that in this forum the Aussie UDT is praised from time to time (and righteous so, I guess) by him I suspect it's the Collins...

Oyashio Class, JMSDF.

 

[gf0012-aust]

It really is a shame gf won't tell which one it is... but given that in this forum the Aussie UDT is praised from time to time (and righteous so, I guess) by him I suspect it's the Collins...

it's not Collins.

 

[swerve]

Oyashio Class, JMSDF.

Sōryū is in the water now, but AFAIK (not that I really know anything about her), her improvements over the Oyashios are in other areas than diving depth. Big beastie, for an SSK.

 

[crobato]

Sōryū is in the water now, but AFAIK (not that I really know anything about her), her improvements over the Oyashios are in other areas than diving depth. Big beastie, for an SSK.

I don't really know where the improved Oyasho class to describe the Soryu came from. From the photos, she looks a lot more closer to an enlarged Gotland class than any other type, complete with X tail.

 

[gvg]

official diving depth of the walrus-class submarines is +200 metres, anything else is pure speculations, as well as most things discussed here about submarines i'm affraid.. As a submariner i can guess wich subs equal or pass the 214's diving depth but ofcourse that would also be pure speculations

The official divin depth off the walrus class is 0m (zero), as the Dutch MoD lists it as "classified", without mentioning any number.
I'd say the unofficial depth is 'at least 50% more than it's predecessor'. Because that was one of the criteria for this class.

 

[Lostfleet]

I am not familiar with sonar systems that much so I have a question about active sonar systems,

As far as I know active sonars is better to detect SSKs but what are the detection ranges with active sonars either from ship platforms or helicopter dropped buoys ?

"by the way If I am wrong saying active sonar is better to detect SSKs please tell me because all I know about submarine detection is from Jonesy listening to whales and underwater earthquakes to catch a Soviet Sub"

 

[vivtho]

I am not familiar with sonar systems that much so I have a question about active sonar systems,

As far as I know active sonars is better to detect SSKs but what are the detection ranges with active sonars either from ship platforms or helicopter dropped buoys ?

"by the way If I am wrong saying active sonar is better to detect SSKs please tell me because all I know about submarine detection is from Jonesy listening to whales and underwater earthquakes to catch a Soviet Sub"

While I am not a sonar expert myself, from conversations I've had, my understanding is that passive sonar has a much longer range than active sonar, especially when there is a strong thermal layer creating convergence zones. However, using a passive sonar it is much more difficult to get an accurate range and (to a smaller extent) bearing to the contact. Using an active sonar will instantly give you range, bearing and elevation of the target, but is much shorter ranged and gives away your position to everybody in the vicinity.

To answer your question, it is difficult to give a straight answer about an active sonar's range because the performance of any sonar depends a lot on the environmental conditions - the bottom type (rock, mud, sand etc), the presence of a layer, presence of water currents, quality of anechoic coating on the submarine, the output of the sonar transducer etc.

In general the standard tactic used by surface and airborne combatants is to avoid using active sonar unless the target is already within (or close to) torpedo range. Using it at longer ranges is either an invitation to the submarine to attack you, or a warning to get out of the area before being detected.

 

[crobato]

While I am not a sonar expert myself, from conversations I've had, my understanding is that passive sonar has a much longer range than active sonar, especially when there is a strong thermal layer creating convergence zones. However, using a passive sonar it is much more difficult to get an accurate range and (to a smaller extent) bearing to the contact. Using an active sonar will instantly give you range, bearing and elevation of the target, but is much shorter ranged and gives away your position to everybody in the vicinity.

To answer your question, it is difficult to give a straight answer about an active sonar's range because the performance of any sonar depends a lot on the environmental conditions - the bottom type (rock, mud, sand etc), the presence of a layer, presence of water currents, quality of anechoic coating on the submarine, the output of the sonar transducer etc.

In general the standard tactic used by surface and airborne combatants is to avoid using active sonar unless the target is already within (or close to) torpedo range. Using it at longer ranges is either an invitation to the submarine to attack you, or a warning to get out of the area before being detected.

Actually you are making the differentiation between low, medium and high frequency sonars, basically what you are saying about active sonars here actually apply to med and high frequency sonars. Passive and active sonars apply to all three.

 

[Lostfleet]

While I was watching History Chanell the other day, there was some documentary about submarines and they told that Alfa Class submarine operating somewhere close to Murmansk at full speed was so noisy that its sonar signature was picked up all the way from Bermuda. Can this be true for passive sonar?

 

[gf0012-aust]

While I was watching History Chanell the other day, there was some documentary about submarines and they told that Alfa Class submarine operating somewhere close to Murmansk at full speed was so noisy that its sonar signature was picked up all the way from Bermuda. Can this be true for passive sonar?

There have been instances of subs detecting sounding charges going off from over 1000nm away....

 

[Chrom]

There have been instances of subs detecting sounding charges going off from over 1000nm away....

I know a leading scientist from Vladivostok Pacific Oceanological Institute. He tell us sometimes they can hear motor sounds from other side of ocean - up to America. There is certain depth layer in ocean which can serve as waveguide, transporting sound thousands miles across ocean.

Now active sonars: They are mostly used when searching for quite close, but very silent target. F.e. sub laying on ground.

 

[Salty Dog]

While I was watching History Chanell the other day, there was some documentary about submarines and they told that Alfa Class submarine operating somewhere close to Murmansk at full speed was so noisy that its sonar signature was picked up all the way from Bermuda. Can this be true for passive sonar?

There have been instances of subs detecting sounding charges going off from over 1000nm away....

I know a leading scientist from Vladivostok Pacific Oceanological Institute. He tell us sometimes they can hear motor sounds from other side of ocean - up to America. There is certain depth layer in ocean which can serve as waveguide, transporting sound thousands miles across ocean.

Now active sonars: They are mostly used when searching for quite close, but very silent target. F.e. sub laying on ground.

I remembered this from my ASW days, . . . What you have here is sound travelling in the "deep sound channel".

Wiki gives a basic explanation of the deep sound channel: http://en.wikipedia.org/wiki/SOFAR_channel

"F.e. sub laying on ground."?! - Roll over spot!! <<Sorry, I couldn't resist>>

 

[crobato]

While I was watching History Chanell the other day, there was some documentary about submarines and they told that Alfa Class submarine operating somewhere close to Murmansk at full speed was so noisy that its sonar signature was picked up all the way from Bermuda. Can this be true for passive sonar?

If its on low frequency yes. Low frequency has less attenuation meaning energy loss, as it travels across a medium (Its true for both radar and sonar).

The deeper the water, the more dense it is, the more sound can propagate.

 

[Firehorse]

Sōryū is in the water now, but AFAIK (not that I really know anything about her), her improvements over the Oyashios are in other areas than diving depth. Big beastie, for an SSK.

The Tango class has bigger dimensions than the Oyashios & new Sōryū class.

The larger hull size of the Tango also enabled it to have a significant battery capacity. It can stay underwater for more than a week before snorkeling is required. In fact they have an overall performance comparable to its nuclear counterparts.
The propulsion system was an outgrowth of the one used on the later Foxtrot submarines. They were designed to be used in an 'ambush' role against NATO warships operating at choke-points on the sea lanes.
http://www.russianwarrior.com/STMMain.htm?1979vecindex.htm&1

I mentioned on another tread that Romania has 1 inoperational Kilo SSK. I wonder why noone in the West offered to buy it for training & evaluation purposes and/or to sell it to Taiwan?

Mods: I know that Wikipedia isn't a very reliable source, but there are list of links that anyone can check for cross-reference.

 

[kato]

Romania has 1 inoperational Kilo SSK[/URL][/B]. I wonder why noone in the West offered to buy it for training & evaluation purposes and/or to sell it to Taiwan?

Because that would cost significantly more money than e.g. training vs the Polish Kilo or the Indians?

 

[Firehorse]

I just found this-

Romania To Reactivate Sub "Fleet"
..The Ministry of National Defence will spend some 50m euros for the reactivation of the only submarine of the Romanian Naval Forces.
"The Minister of National Defence Teodor Atanasiu, attending on Wednesday [24 August] the works of the Summer School of the Liberal Youth, told Rompres that the budget for the next year will include a special chapter for the reactivation of "Delfinul" submarine.
"Atanasiu said that the operation might cost up to 50 million euros. The minister said that the submarine is a redoubtable naval element for the national safety and discourages any possible threats against Romania. The Romanian army cannot afford to give it up as it might support the newly acquired British frigates "King Carol" and "Queen Mary". [Hyperlink mine] "It is an important weapon for any army in the world and we must not forget that this generation of submarines, that "Delfinul" is part of, is one of the most modern that currently operate in the Black Sea," Atansasiu said.
"Delfinul", part of Kilo class, is built in the former Soviet Union and was bought by the Romanian Naval Forces in 1981. It has a displacement of 2,300 tonnes surfaced and 3,000 tonnes submerged, 72 metres length, and is equipped with a diesel-electric propulsion that propels the ship with 20 knots submerged."
The 50M euros is a substantial portion of the Romanian naval budget (normally about $830M euros). This report, plus the news that Romania is taking the rotating command of the Black Sea Naval Cooperation Task Force, as well as reports of recent exercises with the U.S. Navy, all show that Romania is ready to take their rightful place in naval leadership in the Black Sea. The other big hurdle, of course, will be training the crews of the refurbished boat. I hope that they'll investigate a partnership with the Poles, who have shown significant proficiency in operating their Kilos.

It was mentioned on another tread that a NK sub was once spotted off the African coast. I searhed but wasn't able to find anything on this. What was it doing there?

 

[gf0012-aust]

It was mentioned on another tread that a NK sub was once spotted off the African coast. I searhed but wasn't able to find anything on this.

thats why the internet is a limited resource. It was an article in Proceedings about 3 years ago. Printed edition. I'm a Life Member of USNI so I only get hard copy. I assume that there are a few others (Galrahn and RickUSN) who get it.

What was it doing there?

generally you don't get the opportunity to ask what your opposing number is doing. its not the way things are done....