ASW technologies and techniques

[gf0012-aust]

True enough. From "The Third Battle"

there are a few errors in that citation.

the british were rafting long before the USN kitted out Thresher.
the Soviets/Russians still struggled with the SOSUS grid well into the 90's. Elements of the grid that haven't been deactivated are more than capable of picking up other subs (incl nukes). Russian nukes varied in their signature suppression considerably from class to class. even within a class vessels can be readily identified as each ship and boat has an identifiable signature once its been mapped.

 

[Firn]

there are a few errors in that citation.

the british were rafting long before the USN kitted out Thresher.
the Soviets/Russians still struggled with the SOSUS grid well into the 90's. Elements of the grid that haven't been deactivated are more than capable of picking up other subs (incl nukes). Russian nukes varied in their signature suppression considerably from class to class. even within a class vessels can be readily identified as each ship and boat has an identifiable signature once its been mapped.

It don't want to nitpick but if you read the quote againg it doesn't include rafting among the technologies first adopted for the Thresher

Anyway I think that it is clear that SOSUS is still able to detect submarines - even if at (far) shorter ranges, given the reduced signature. The sound mapping was an really impressive team effort, and one which continues of course even today. A video documenting the frightening power of an Torpedo

[ame="http://www.youtube.com/watch?v=rdLHkqrwb7g&feature=related"]Torpedo Test[/ame]

Thanks gf0012-aust btw, it is always good to get a far better educated opinion than his own.

 

[gf0012-aust]

It don't want to nitpick but if you read the quote againg it doesn't include rafting among the technologies first adopted for the Thresher

This in turn indicates that rafting and other, more advanced quieting techniques first adopted by Thresher in the United States

Badly worded then - but it looks like it to me!

The sound mapping was an really impressive team effort, and one which continues of course even today. A video documenting the frightening power of an Torpedo

Hence CBASS/ADCAP. It uses quad processors, digital on board links, onboard database as well so that it"fishes" off that database of signatures. Plus it's dynamic in its processing.

All of the sound mapping on its database is based on signature mapping done by RAN and USN - and includes the sig mapping work developed in Australia by ex RAN submariners for the Collins and adapted for a weapons system solution.

 

[Firn]

The efforts and the challenges of sound mapping are certainly one of the most important areas in undersea und ASW warfare. Talking about networked sensors:

NURC publication

A thougth provoking article.

Underwater Electromagnetic Progagation

Kongsberg UUV line

 

[Transient]

Hence CBASS/ADCAP. It uses quad processors, digital on board links, onboard database as well so that it"fishes" off that database of signatures. Plus it's dynamic in its processing.

All of the sound mapping on its database is based on signature mapping done by RAN and USN - and includes the sig mapping work developed in Australia by ex RAN submariners for the Collins and adapted for a weapons system solution.

Does the CBASS still use a copper cable connection to the sub like earlier variants, or has it transitioned to a fibre-optic cable?

 

[Firn]

ASW and submarines around the Falklands:

Hardly any conflict in the last thirty years put the surface fleets of two nations in such perils as the conflict around the Falklands/Maldivas. The sheer amount of ressources needed to sustain the ASW efforts fall pretty much in line with the previous experiences. It is especially an interesting conflict because the Navy's focus during the Cold War was ASW - still they had an asthonishing deal of trouble with a single Type 209 which was certainly not manned and maintained by a first-class force.

Beyond the General Belgrano and Sheffield

Perhaps the most disturbing lesson of the war is in the realm of Anti-Submarine Warfare (ASW). Argentina had only four World War II-era diesel submarines, two of which were tied up in port: the Salta’s battery was depleted (although the Argentines moved it around to confuse the British) and the Santiago del Estro had been cannibalized for spare parts.8

As mentioned above, the Santa Fe was damaged early in the war and thus remained inoperative throughout the conflict. However, the British spent an extraordinary amount of time trying to track these few submarines. An enormous amount of ordnance was dropped on false contacts, while Sea King antisubmarine helicopters constantly patrolled the area.9 Their efforts were confounded by the difficulty to conduct sonar operations in shallow water.10 That the British spent so much time and firepower ineffectively chasing one outmoded diesel submarine shows both the difficulty of ASW and the deadliness of even older submarines to a large surface fleet.

Note that here there is an error as the U 209 was certainly not a World War II relict.

Indeed, the San Luis fired several torpedoes on British ships, yet each torpedo missed its target. It is suspected that “synchro misalignment had caused incorrect bearing information to be transmitted from the periscope to the fire-control console,” and that furthermore an “overzealous
leading petty officer…had incorrectly reconnected lead used to power-up torpedoes in their tubes before launch.”11 This shows that one must not only have the technology—one must also be well-trained in using it effectively.

Around the corner (German) also points toward the conclusion that the poor training and the sorry state of the Argentinian Navy. The crew not had even trained the torpedo launches at the simulator, maintenance was very poor. The crew only had 2 months on the boats under their belt.

Erst Ende September klärte sich der Gerüchte-Nebel. Argentinische Militärs reisten nach Norddeutschland, um den Fortgang einiger Kriegsschiff-Bauten zu begutachten, die in Ostfriesland und Hamburg fertiggestellt werden. In Emden bei den Thyssen Nordseewerken schauten die Südamerikaner nach drei neuen U-Booten, in der Hansestadt baut Blohm + Voss an vier Fregatten für die Südamerikaner.

Während des Besuches erzählten die Argentinier dann zerknirscht, was die Deutschen von ihnen hören wollten: Den Mißerfolg der bundesdeutschen U-Boote verdankten die Südamerikaner ihrer eigenen Schlamperei, mitnichten aber der Unfähigkeit norddeutscher Waffenproduzenten.

Eines der beiden gut 100 Millionen Mark teuren Boote, die "Salta", lag zu Beginn des Krieges unbrauchbar, offenkundig mit einem Maschinenschaden, im Hafen. Das zweite Schiff, die "San Luis", wurde zwar eingesetzt, war aber denkbar schlecht auf ein Gefecht eingerichtet. Die Besatzung des Bootes war S.120 erst knapp zwei Monate vor Ausbruch des Krieges frisch an Bord gekommen. Mit den komplizierten Elektronikwaffen konnte die neue Mannschaft wenig anfangen. Probeschüsse, wie sie in der Bundeswehr an Simulatoren üblich sind, hatten die Matrosen nicht geübt.

This source also seems to agree with this assessment.



From the first link:

The British had to provide the “bullets and beans” to supply its sailors and troops fighting a war 8,000 miles away from home. They accomplished this by two methods: First, they established a “forward” base at Ascension Island, airlifting stores and troops to the island early in the conflict.26 Though the island is still 3,750 miles away from the Falklands, it cut in half the distance necessary to resupply the British fleet. Second, the British utilized their substantial merchant fleet to ship supplies from Ascension Island to the task force. This “particularly ingenious solution” involved using a number of civilian vessels, including the luxury liner Queen Elizabeth II, to transport both troops and materiel.27 Of course, the plan worked mainly because the Argentineans failed to attack these merchant vessels. The Argentineans essentially made the same mistake that the Japanese had in World War II: by attacking military vessels rather than the slower-moving, more poorly-defended logistics ships that supplied them, they failed to halt the British fleet. Indeed, the only logistics ship hit by the Argentineans was hit by accident: the Atlantic Conveyor was badly damaged by a missile intended for another ship.

BTW: Certainly it is interesting to see how "infamous" the German U-boat campaigns were, and how eagerly the US attacked Japan with almost exactly the same ruleset - perhaps even with some harsher aspects - against Japan. And how not attacking the merchant ships of the allies in the Pacific and the ones of the British is a "mistake".

 

[Firn]

Here is a not sourced article from an Argentinian view. Due to the compound and heavy evidence in the well sourced first articles I think it should be taken with some graines of salt regarding the issue of the source of errors which caused the problems on the San Luis .

During the Falklands/Malvinas war, a single Argentine Type 209 managed to elude 15 British frigates and destroyers and the antisubmarine aircraft of two carriers. The San Luis maneuvered into torpedo range of the British fleet and launched three torpedoes, although all three shots were unsuccessful. Early in the conflict a British submarine sank the Argentine cruiser General Belgrano with two straight-running torpedoes of a design that dated to World War II.

San Luis reported two attacks on Royal Navy ships during the war. On May 1, 1982 the ships HMS Brilliant and Yarmouth were sent to hunt down the San Luis operating north of Stanley. San Luis reported firing one German-made SST-4 torpedo at the ship which subsequently missed.

San Luis attacked again on the night of May 10. Alacrity had made passage up Falkland Sound, sinking an Argentine merchant navy ship on the way. As Alacrity left the channel before dawn, its sister ship Arrow was waiting to escort her back to the Task Force. San Luis detected the two ships and fired two SST-4 torpedoes upon them. But the first torpedo didn’t leave its tube and the second one was fooled by the Arrow’s torpedo decoy.

San Luis returned to Puerto Belgrano on May 17 in an attempt to fix her weapons system but the war ended before she could sail again.

The U.S. chief of naval operations at the time, Admiral Thomas Hayward, confirmed this assessment twenty years later. As the Falklands campaign reached its climax, “Britain was on the edge. One more loss” of a naval combat or support vessel, “and Thatcher could not have sustained” the war. A hidden factor was the “brand-new” and well-trained Argentine submarine force. If one of its boats had managed to put a torpedo or two into the Queen Elizabeth or another vessel, “that was it.” But combat revealed a fatal flaw in the torpedo control software system, and the submarines never came into play.

Detail

Frigate Captain Azcueta was ordered to make ready his submarine (ARA San Luis) and sail to the Falklands.

The ARA San Luis was a Type 209 submarine, built in 1974 and it’s condition wasn´t the best: refrigeration ducts and main structure covered with incrustations. Due to the need of getting ready quickly , divers started the cleaning operations because Mar del Plata’s base lack of a dry dock.

When the job was finished, the ship was re-supplied and armed with SST-4 and Honeywell Mk37 torpedoes.

By April 11th ARA San Luis was at the sea, travelling to the Falklands. During one of the exercises the fire director computer broke down. Azcueta informed his superiors, but with the lack of any other submarine (ARA Salta was at the dry dock) the mission had to continue.

The first contact with the enemy navy was in May 1st, when the sonnar detected the presence of one target- classified as a destroyer.

At 1015 hours the San Luis launched an SST-4 to the target, but it failed due to the torpedo-cable being cut. Then the sub was then attacked with depth charges, but managed to escape from its pursuers.

The last “offensive” mission took place May 11 at 0140 when San Luis launched a SST-4 torpedo at one target classified as frigate, but again the torpedo cable failed.

Frigate Captain Azcueta broke radio silence and informed Naval Command of his situation. The order was given return to the base and try to repair the fire director.

By June 14th personnel of ARA San Luis were still trying to fix the sub to return to the Falklands.

The problem with SST-4 was in the fire train , that caused the explosion of the war head and the unrolling system of the torpedo cable.

Perhaps I will also look at some other sources from Argentine.

 

[Firn]

A good overview of the Falkland conflict

The other two submarines were West German "Type 209" vessels built in 1974--Salta and San Luis. The Salta saw no action but the San Luis, also suffering from maintenance problems, did operate against the Royal Navy. Foreign technicians returning from Argentina reported that the San Luis deployed in mid-April with one of its four diesel engines inoperative the main torpedo fire control system inoperative and a crew which had experienced a fifty percent turnover only a week earlier. The fatal blow in the ship's performance, however, was a reversal of two wires in the target angle synchro in the emergency fire control panel. The problem was compounded by an apparent failure on the part of the operators to realize that the panel then had no provision for feedback from the wire-guided torpedos after they were launched.13 They, therefore, couldn't give the torpedo command guidance enroute to its target.

The San Luis reportedly did manage to conduct an attack. The submarine fired three MK 37 and three or four West German SST-4 torpedoes at surface ship targets. All were reportedly fired at ranges of 8000 yards with the submarine at maximum operating depth. No hits were achieved. The submarine subsequently returned to its base. Apparently that submarine spent the remainder of the war in port while technicians attempted to repair the fire control computers.14

 

[Firn]

SUBMARINE OPERATIONS DURING THE FALKLANDS WAR

Economy of Force. This is where submarines shine; "there is no more cost effective weapons platform than the submarine.' They are small, compact, but carry a powerful punch. By operating submerged, submarines do not require many of the expensive self protection systems that surface warships require. To avoid most threats they just need to submerge. While a surface ship has to be concerned with defending against attack from missiles and bombs, submarines do not, unless they are on the surface as was the Santa Fe when she was attacked.

The war also reinforces what was already plainly visible after a harder look at the Battles in the Atlantic. A long range recce aircraft (Kondor) and submarines (U-boats) make an excellent combination, especially if vast areas have to be searched. Perhaps there is truly some space for an SSK TUAV carrier, with ISR and SIGINT vehicles

 

[Firn]

About the SSK TUAV carrier.

Scaneagle video


The catapult can be made more compact according to Insitu. As a matter of fact it should not be too difficult to create a SSK of the U 212A's size with an integrated TUAV launcher. The catapult (page 5) would telescop out of the rear part of the sail and loaded from inside (preferable) or perhaps from the outside (easier). The UAV should of course have foldable or plugable wings. There are other alternatives, but so far so good.

A foldable/telescoping mast inside the rear part of the sail would help to retrieve the bird. This almost surly requires surfacing, but a long range TUAV would allow the submarine to stay submerged for roughly a day. It also stay a good chance to fly towards friendly assets far awary.

The crux here is of course lies here in C&C. I fancy that a combination of preprogrammed flight and communication via relays and sattelites would solve that. All in all an interesting idea which already surfaced (no pun intended) during WWI.


Raytheon's SUB SUAV offers a neat launchtube. Certainly a great idea, if it works.

The German SUAV requires the submarine to be at periscope depth.

 

[gf0012-aust]

TUAV carrier.

USN has run UAV's from subs at least 5 years ago via USS Florida (before her SSGN conversion). This was done via events such as Ex Silent Hammer.

In the last 4 months they've done a full Reaper sized launch (apparently).

AFAIK Tube, Sling and Hand launched have all been done.

 

[Grand Danois]

Le Monde: The black boxes of the Airbus Rio Paris identified

Systran.

 

[Firn]

USN has run UAV's from subs at least 5 years ago via USS Florida (before her SSGN conversion). This was done via events such as Ex Silent Hammer.

In the last 4 months they've done a full Reaper sized launch (apparently).

AFAIK Tube, Sling and Hand launched have all been done.

Thanks. Already in WWI it was visible just how profitable such a marriage could be. It is really exciting to see this new developments. A full MQ-9 Reaper sized launch?

Anyway an SSK with a catapult with an couple of stored TUAV with an endurant UAV would have very interesting capability matrix.

 

[Bonza]

USN has run UAV's from subs at least 5 years ago via USS Florida (before her SSGN conversion). This was done via events such as Ex Silent Hammer.

In the last 4 months they've done a full Reaper sized launch (apparently).

AFAIK Tube, Sling and Hand launched have all been done.

Not to interrupt the enlightening discussion, but out of curiosity GF, what do you make of the developments going on for the German Type 212 submarine (retractable mast with 30mm Rheinmetall cannon/UAV launch capacity, and tube-launched IDAS anti-air missiles)? To me the capability increase seems quite significant (and quite unusual, as far as the cannon armament goes), but I'd be interested to hear what you have to say on the subject, given your knowledge.

 

[kato]

(retractable mast with 30mm Rheinmetall cannon/UAV launch capacity, and tube-launched IDAS anti-air missiles)?

The Muraena cannon is dead.

New equipment for Batch 2:
- dragged buoy system with SATCOM
- IDAS
- four-man diver chamber
- upgraded sensor equipment
- multi-purpose area in sail (can in theory mount Muraena, or other systems)
- potentially: UUV launch through tubes (no fixed plans though)

 

[Transient]

In the last 4 months they've done a full Reaper sized launch (apparently).

Umm... 'apparently'? Was this piece of info published in any open source literature? What exactly is this UAV? Very intriguing.

 

[STURM]

Hello, sorry for the ignorant questions.... I'd really appreciate some feedback with my queries.

What advantages, besides the longer detection range, does a towed array provide over a hull mounted sonar?

For littoral ASW work, is a VDS or a towed array more useful?

Apart from being able to penetrated the thermalcoline layer what advantage does a VDS provide?

Am i correct in assuming that a surface vessel not fitted with a VDS or a towed array, that just relies on a hull mounted active/passive sonar will a have very much harder job detecting a sub... or does it depend largely on water conditions, range, noise generated by the sub, etc.

Can modern wire torps like Blackshark, Mk48, Spearfish be used against a moored target that is not generating any acoustics?

Thank you.

 

[Systems Adict]

Hello, sorry for the ignorant questions.... I'd really appreciate some feedback with my queries.

What advantages, besides the longer detection range, does a towed array provide over a hull mounted sonar?

For littoral ASW work, is a VDS or a towed array more useful?

Apart from being able to penetrated the thermalcoline layer what advantage does a VDS provide?

Am i correct in assuming that a surface vessel not fitted with a VDS or a towed array, that just relies on a hull mounted active/passive sonar will a have very much harder job detecting a sub... or does it depend largely on water conditions, range, noise generated by the sub, etc.

Can modern wire torps like Blackshark, Mk48, Spearfish be used against a moored target that is not generating any acoustics?

Thank you.

Mmm..

Let's break it down...

#1. Having your sonar 'attached' to the hull means that you effectively have a 'wooded arc' behind the ship (+ / - 10 to 15 degrees possibly ??). In addition, the sonar has to overcome the 'noise' of the hull which is like tying to listen to a recorded conversation of two people talking, while the mike is planted in front of a loudspeaker, pumping out rock music !

#2. VDS or Towed array, mmm... In the littorals, the depth is usually less than 30 metres. While a towed array may give your better area coverage, you may have problems trying to reel in 1km of cable, while traveling at a reasonable speed to escape from 'an enemy', while trying to ensure the tow stays off the bottom. A variable depth sonar maybe a better option, but you'd need to be pretty sure of your bottom layout, so that you don't hit something unexpected. Littorals would be a better place to use a hull mounted sonar.

#3. That all depends on the quality of the equipment & the software associated with it....

#4. Why not ?? ANY vessel in the water will 'reflect' active sonar signals. Added to the fact that any submariner worth their salt will use ALL data available, from the the ships main sonar picking up noises from machinery / waves lapping against the hull & providing noise, to actually looking thru the periscope & guiding the fish onto target.

Most of these comments are pretty much common sense, but I'm sure some of the more 'educated' people here may correct any errors, or provide more meat to the bones.....

SA

 

[pingjocky2]

active/passive sonar

You might have come across material on the AN/SQS-23 PAIR which were (2) hull mounted sonar domes found on the USN DDG-2 (Chales F. Adams) class. I recall the front dome was active/passive whilst the rear dome passive only.

If you are active you are putting sound into the water and listening for a return in passive mode you simple are listening for sounds associated with your targets.when you ping a burst thats all you'll hear is that ping so passive is nullified

 

[oktober]

If you are active you are putting sound into the water and listening for a return in passive mode you simple are listening for sounds associated with your targets.when you ping a burst thats all you'll hear is that ping so passive is nullified

What matters most is your entire ASW network, comprising aircraft, surface vessels, satellities, submerged assets, deployed sensors and known areas of sanitization, with the three keys being effective sensor/information sharing, effectiveness of this node to communicate without information disruption, and processor architecture to filter/disseminate between relevant and non relevant contacts in your mission area. If your relying on one sub/ship, and its inherent sensor suite, and nothing else, spen $50Billion USD if you like, the outcome will be the same. Loss of situational awareness, and thus effective control of your forces, and soon attrition/stalemate/loss/high casualty rate non-acceptable victory.

There IS a Link 16 for the naval, underwater warfare spectrum. Do not forget.