Surface vessel decoys and countermeasures
 

Quoted posts start from here.


Started a new thread to avoid hijacking the RAN thread.

With respect to the countermeasures discussion, my question about the realistic impact of an anti-torpedoe countermeasure was more about how often a heavyweight torpedoe is/would be fired against a surface vessel, and have the torpedoe be forced to rely upon its own onboard guidance package.

With many of the AShM's available out there, the expectation is that the missiles would be fired against OTH targets, beyond the detection and guidance capabilities of surface, subsurface or even aerial launch platforms. With that in mind, the anti-missile countermeasures need to defeat the guidance package of the inbound missile.

I also expect that countermeasures like chaff are more of a last ditch effort, since they would be used against incoming missiles which have leaked through an area air defence umbrella, and apart from the countermeasures, the only other hardkill systems possibly available would be CIWS. Active softkill systems like Nulka IMO are likely more capable, but again seem primarily intended as part of a final effort.

Against torpedoes the question still remains, how often would a heavyweight torpedoe be fired from a sub, when the range is further than the sub could provide guidance updates? If most surface vessel warshots are taken with guidance from a sub, then the surface vessel's countermeasures need to be able to disrupt/defeat not only the torpedoe's onboard guidance package, but also the sensors and combat data system of the attacking sub.

-Cheers

Thank you for opening a new thread to deal with my queries. I've always been interested in naval self-defence systems but I, admitedly, know little of the technologies involved.

And the only soft kill option is by means of chaff or an oboard active jammer, which may or may not be effective against that particular missile which may in turn be fitted with home on jam technology.

Chaff is indeed a last ditch effort for ships that are targeted by sea skimmers but lets face it, only a handful of navies have the luxury of being able to call or rely upon on a multi-tiered defence layer - from fighters or MPAs to deal with ships and subs before they can fire, to long and middle range surface to air missiles to deal with the missiles that get through. For most navies, chaff and guns - and if they're lucky to have missiles - are the main means of dealing with sea skimmers.

Correct me if I'm mistaken, but am I correct in saying that live tests have only been done against subsonic drones that were used to simulate sea skimmers and that only simulated computer based tests have been performed against supersonic sea skimmers? If that's the case, how do we know with any certainty that ESSM, Standard, Aster 30/15 and gun based CIWS can indeed deal with supersonic threats? The Indian Navy [IN] experience with Kashtan for me is a prime example of the importance of during realistic evaluations on systems rather than taking what the manufacturer claims at face value. During trials conducted in the Baltic, the IN discovered that Kashtan could not hit targets flying at a certain [low] altitude which was the complete opposite of what its manufacturer had been saying.

Yes but short of actually destroying the launching platform how is it technically possible to defeat the torps guidance package, by what means?

All in all, I think the fact remains that although most ships are fitted with chaff launchers to deal with air threats, many are not fitted with torp decoys, when it can be argued that in a littoral enviroment, subs may pose a bigger threat. It probably boils down to funding issues.

Might possible scenarios arise in littoral waters?

Assuming that torpedoes can maneuver outside the view of the sub's sensor systems, one could imagine a torpedo fired from a sub lurking at the bottom of a fjord arm, turning 90 degress upon exiting the fjord, then hitting a large surface combatant at the entrance to the main fjord.

However, I don't know whether the torpedoes are capable of this. If they are, then subs could also hide behind islets at the outer edges of archipelagoes and fire at large surface combatants that are several miles off shore.

Off the top of my head there has been a case of an Aster 30 (PAAMS) launched from a Horizon class 'frigate' from the MN successfully hitting a supersonic sea skimming Coyote drone in tests earlier this year :)

French Navy frigate successfully intercepts supersonic sea-skimming missile - Naval Technology

Thanks for the information Rob.

I'm very curious as to why Raytheon has not announced the results of similar tests they surely have conducted with Standard and ESSM.

Keeping in mind that I am doing this from memory, and still operating under a sleep deficit due to events in my region, here goes...

Chaff is a softkill countermeasure, but so is Nulka. The crucial difference being how they achieve a softkill. Chaff is intended to create a 'cloud' if one will, of radar reflective material between the inbound missile and target ship. If things go as intended, the radar seeker in the AShM gets either no, or a significantly weaker radar return, because the 'cloud' disrupts and redirects the signal. This can cause the lock to break, so that the AShM seeker has to reacquire the ship, otherwise the missile flightpath can go harmlessly away from where the target is.

Nulka OTOH is an active softkill countermeasure, using seduction systems to spoof the AShM seeker into targeting the decoy instead of the ship.

With respect to high speed target drones, IIRC at one point the US was using ex-Soviet/Russian supersonic AShM's as target drones. Following the fall and break up of the USSR, there had been many such missiles available on the open market, and the purchase price was actually lower than the target drones being developed within the US to replicate the AShM flight profiles the US wished to test defences against. After a period of time, Russia did put a stop to practices which allowed the US to purchase high speed AShM. IIRC one of the things which the US learned from such test intercepts, was that a number of the smaller air defence systems (like Phalanx) were starting to be of limited viability. It was not so much that such systems could not achieve hits on the inbound missiles, but that the missiles already had so much KE that even if the missile broke apart in flight missile fragments would still strike and damage the vessel. This is why the calibre of some type weapons was increased (like the Millenium Gun) and others were given a longer engagement range (like ESSM).

As for how to counter the guidance package of an inbound torpedoe... Something could be put into the water between the target vessel and incoming torpedoe to generate sonar returns (like a noisemaker) and hope that the torpedoe is using a home on sound guidance. If the torpedoe head is actively pinging though, then a great deal of noise might need to be generated to damage the 'ears' or something needs to be in place in the water to otherwise disrupt how the return pings get back to the torpedoe, at least until the torpedoe is too far away from the target. Given that some heavyweight torpedoes have estimated ranges of 50 km depending on speeds I do not forsee a reliable way to stop a modern inbound torpedoe.

-Cheers

A Norwegian frigate supposedly shot down 6-out-of-6 GQM-163A using ESSM a couple years ago.

GQM-163A is considered too pricey for the USN to waste in regular fire-to-kill exercises. Especially since they're apparently actively modifying the system the last couple years to simulate high-speed high-diver targets such as ballistic anti-ship missiles and anti-ship cruise missiles with supersonic terminal stages.

There have definitely been live tests in the past involving supersonic sea-skimming drones simulating anti-ship missiles as there are a range of US drones specifically designed for this purpose, as Kato mentioned. If I remember correctly the USN has previously used converted Talos anti-air missiles (which are obviously supersonic, though I don't know about their flight profile or how it was changed) to simulate AShMs. I'm sure there are other systems that could quite feasibly be used in this role too.

I'm not sure what the balance is like between "live" and "live-fire" exercises (Kato mentioned a bit about that too), but it has definitely been done in the past.

Towed decoys
 

I am so far out of date with the latest towed decoys, I'm back in the days of 2 steel bars rattling together to make white noise.
It seems the 2 most common current systems are the USN - AN SLQ-25A and C (RAN uses FEL SLQ-25C) and the RN Ultra Electronis SSTD Type 2170, which was co-developed with the USN before cost got in the way.

Can anyone expand on what is available apart from the usual net sources? Are they effective against smart heavyweight torps? Is there other developments etc, etc.

Cheers

On ESSM testing the Dept of Testing and Evaluation had this to say in 2005


"FOT&E-1 occurred in March 2005 on USS Momsen
(DDG 92) in accordance with a DOT&E-approved test
plan. Testing included a stream raid presentation of two
supersonic maneuvering targets. One of the targets failed in
flight, and ESSM capability against the other target was not
demonstrated."



http://www.dote.osd.mil/pub/reports/...y/2005essm.pdf

This link here is a bit more upbeat however

Aegis Baseline 7 Tested Against Supersonic and Subsonic Anti-Ship Missiles


I guess the question is has it been demonstrated vs a manoeuvring supersonic target - Sea Dart and Sea Wolf were both tested vs supersonic sounding rockets in the 70's for instance, but I doubt either could handle a manoeuvring missile.

Thanks for the all feedback provided, much appreciated.

What was the official reason given by the Israeli Navy as to why INS Hanit was hit by an C-802 without its Phalanx even engaging the target? Was the ship's crew even aware that it had been 'painted' by a shore based radar and that it had been fired upon - or was it a case of the Phalanx being switched off, like the incident with USS Stark?

This link has some interesting bits in it.

http://www.navweaps.com/index_tech/tech-103.htm

Information Dissemination: INS Hanit: Stories From the Sea (Part #1) The official reason was always that the crew was not expecting any ASCM attacks and had no air defense systems on. Thus, as your link notes, Phalanx doesn't work in the OFF position.

See also here. http://www.strategypage.com/militaryforums/36-22440/page2.aspx

There are several goodies that can be launched out of a SRBOC launcher in addition to chaff and flares. Such as seduction and distraction rounds.
Basically a surface combatant can make a very confusing electronic picture for any attacker
Also when a ship is deployed to a particular region there are intelligence briefs for each watch section that includes intelligence on what the likely threats are and, based on what is known, how best to counter those potential threats.

The USN has an old remote control Spru-can it regularly shoots several types of supersonic and subsonic sea skimmers at (well they aim behind it at a barge stacked with con-ex boxes, but they have missed the target and hit the test ship in the past) to test out ESSM, RAM, Nulka and several other point defense weapons with. It is called the Self Defense Test ship and the USN has had several of them.
I work with someone who commissioned one of the early DDG-51's and said during the precomissioning testing they did dozens of live firings against all kinds of flight profiles.

Are there any ASW counter measure nerds out there? See my post #9

C'mon guys, I knew that ASW has taken a back seat since the end of the cold war but really:

Current development over here the last couple years (since the Cold War) was focused on hardkill anti-torpedo measures for surface ships and submarines and softkill decoy arrays specifically for submarines, the latter of which have been successfully introduced.

Nixie is still standard as far as towed decoys go.

If you want something off net sources, try to find out who Finmeccanica WASS has sold their 5-inch rocket based torpedo decoy system, C310, to. Their website says it's currently in production, but you'll have to google a bit to find out for who they're selling to (and you'll only find the UAE - two launchers, three years ago... gee, starting a production line for that? ;)).

Some Polish group was working on a probably rather similar concept using ship-based mortars or blast projectors two years ago btw, if you're looking for something a bit more exotic.