Formidable class frigates

last SG · 2008-04-17T10:21:05+00:00

The palestinians often used home-made rockets that are often one-shot short-ranged, inaccurate but fast deployable precisely cos they are aware of the rapid...

|-|05| SG

Stealth for ships means being smaller then it really is.
Why is that so? Well for one, when the USN first tested out the concept of a stealth ship,The SeaShadow Project, they realised that it worked too well.
The ship did not reflect any of the radar waves back.
That however meant a problem because the ship was showing up as a blackhole on the radar return.

Why you may ask?
Well due to the nature of the sea, the radar waves actually reflect of the surface of the water and waves which in certain conditions could be up to 8m-12m high.All of which produces a pretty significant radar return.

16/f/lonely SG

8-12 is a bit high....

Wonder what it would feel like.

Laughing

SingaporeTyrannosaur SG

which navy ship is really Stealth?tell me?

SG frigate ''appear no larger than a fishing boat on enemy radar.''

or the most a 500 tons fishing boats.

http://www.dso.org.sg/home/newsevents/newsevents_showpage.aspx?id=17

http://www.globalsecurity.org/military/world/taiwan/kang-ding.htm

A captain of a la fayette class said the frigate appears one tenth

of its original size in radar.

500 tons? Not unless you believe the obviously Taiwan slanted written article on global security.

Another imaginary figure it seems...

Here's from a more realistic source

At the time of their commissioning, the units of the La Fayette class were the state of the art in stealth for warships. The shape of the hull and the superstructures is devised for the optimal reduction of the radar signature, which has been reduced by 60%: a 3000-tonne La Fayette unit has the typical radar signature of a 1200 tonne ship.

BTW, even if it is 500 tons, it'll still be as visible to enemy radars as our 500 ton Fearless Class PVs.

And of course, to have stealth means that you have to becoming totally passive, turning off your radars and anything that generates EM radiation, which also means reducing your own combat-effectiveness to passive listening.

This is not to say the low-observability features of the Formidable has no uses, but in pratice it's not as wonderous as it's cranked out to be, you'll have to sacrifice a lot of things to get the advantages of staying hidden longer.

SingaporeTyrannosaur SG

which navy ship is really Stealth?tell me?

Another case of you not doing your homework.

For a truly stealthy navy ship:

And of course, for true naval stealth that is in common useage:

A prime example of extreme stealth would be the ability to penetrate the USN's ASW dragnet.

SingaporeTyrannosaur SG

Our "stealth" is nothing special. It's more of pseudo-stealth actually, which is simply a first-generation redesigning of traditional ship shapes to make them more sensible in terms of RCS. But tactically it is better classified as low-observable then true stealth- as in the utility of stealth is a feature, and not the main defining feature that will affect the tactics of how you'll use the ship ie. true, STEALTH.

The effort to manage naval signature has long been in progress.

Reduction of radar cross section, visibility and noise is not unique to stealth ships, with visual masking employed for over two centuries and RCS reduction tracing back to American and Soviet ships of the Cold War. One common feature is the inward-sloping tumblehome hull design that significantly reduces the radar cross-section.

Trying to use the Formidable to sneak up on an enemy fleet by virtue of it's "stealth" will invite a barrage of ASMs.

The Formidible "stealth" is nothing new, check out the ships of other nations which also use such an idea:

Swedish Visby class corvette,

Dutch Zeven Provinciën class destroyer,

Norwegian Skjold class patrol boat,

German MEKO ships

Braunschweig class corvette

Sachsen class frigates,

Indian Shivalik class frigate,

British Type 45 destroyer,

Finnish Hamina class missile boats

Now lionnoisy, if you really want stealth you don't reduce a 3,200 ton Frigate to a 1,200 ton vessel, you reduce a 14,564 ton DESTROYER to a fishing boat and make it as quiet as an 688I submarine:

The Zumwalt-class destroyer (also known either as the DD(X) or DDG-1000) is a planned class of United States Navy destroyers, designed as multi-mission ship with a focus on land attack. The class, originally called the DD(X), is a scaled-back project that emerged after funding cuts to the larger DD-21 vessel program.

The lead ship is named Zumwalt for Admiral Elmo Zumwalt; following U.S. Navy tradition, it and its sister ships will be known as Zumwalt-class ships.

Stealth

Despite being 40% larger than an Arleigh Burke-class destroyer the radar signature is more akin to a fishing boat and sound levels are compared to the Los Angeles-class submarine. The tumblehome hull reduces radar return and the inclusion of composite materials reducing it still further. Water sleeting along the sides, along with passive cool air induction in the mack reduces thermal emissions.^[5]

what can we say?

Shotgun SG

Not fair to consider the Sea Shadow leh... its not an active ship in combat, but rather a research prototype.

A totally stealth ship thats invisible to radar, is a submarine thats submerged. So they do exist.

As for how the Formidable's stealthy feature works to its advantage, its as I have discussed earlier. At a good distance, its RCS is that of a fishing boat, and a further distance, might be missed out as clutter.

I think its pretty hard for us to guesstimate whether how our "Stealth" will be utilized in combat. Only thing certain is that, it still works to our favor.

SingaporeTyrannosaur SG

Not fair to consider the Sea Shadow leh... its not an active ship in combat, but rather a research prototype.

A totally stealth ship thats invisible to radar, is a submarine thats submerged. So they do exist.

I think its pretty hard for us to guesstimate whether how our "Stealth" will be utilized in combat. Only thing certain is that, it still works to our favor.

Yes correct, what I am pointing out is there's no need to go all lionnoisy over the "stealth" of our frigates, and they certainly ain't no Zumwalt... now that'll be something to boast about.

tripwire SG

the holy truth... we all knew close to zero how much stealth the RSN FFS have.... its an undeniable fact.

we can quote from other sites... about lafayette or similar ships, but the fact remains. we knew an absolute zero about the RSN FFS RCS.

furthermore... the weight of a ship does not determine the ships RCS... if i am correct. plus to the fact that our FFS isnt an exact copy of the lafayette, being smaller with even lower profiles and a close attention to details...one would surmise that the stealth features on our FFS should be superior to that of the lafayette...

its hard to imagine that a ship built in the 2000s could not come with a better "stealth" feature compare to one that was built decades earlier... its sad to see technology stagnant.

but as stealth technology improves... so will radar technology...its a cycle thingy...

ultimately... it boils down to who have the money... to keep raising the stake in this neverending competition since the days man invented the spear and the shield.

38 SG

To reduce RCS is definitely a welcome for any combat vessels, but according to radar equation, the RCS has to be greatly reduced in order to achieve any significant detect range reduction:

σ = radar cross section, or RCS, of the target

R = distance from the target to the receiver

To speak with some data, that is, if the detect range need to be reduced by half ( 1/2th) by means of RCS reduction solely, then the RCS has to be reduced to 1/256^th of the original! A reduction of RCS to 1/10^th of the original will only reduce the detection range of some 13% roughly. Usually a modern fighter can detect a DDG size target up to 300-400kms, reduction of 13% of such a range is really not a big deal. Your AshCM nowadays is still usually up to 200kms.

On the other hand, RCS of a certain target is always NOT a constant! You paint it with S-band radar commonly found in AWACS and you paint it with X-band FCR in a fighter’s c-ockpit will result in totally different RCS of the target. Furthermore, the geometric features in different part of the vessel will result in different RCS as well, which means, if the radar sees the vessel in front at a low angel as a extremely bad case, it will find the vessel a “fishing boat” which may be just 1/10^th of the thousands ton vessel, but how about seeing it from the side a thigh altitude? It may no longer be as “that small” any more.

Modern Naval combat vessels are equipped with state of art EW sensors. In a combat situation, hardly you can image a modern FFG not on its powerful search radar or in some case, highly identical fire control radar. Those radiations can be picked up far far away by passive sensors of the enemy fighter jets. How many "fishing boat" can shoot up thousand kws of radiation into sky? these are broadcasting your location as well. So what Stealth are people talking about FFS?

Again, reduce RCS is definitely a good thing, but nobody will live on that because today’s modern radar and sensor technology is so well developed.

SingaporeTyrannosaur SG

the holy truth... we all knew close to zero how much stealth the RSN FFS have.... its an undeniable fact.

we can quote from other sites... about lafayette or similar ships, but the fact remains. we knew an absolute zero about the RSN FFS RCS.

its hard to imagine that a ship built in the 2000s could not come with a better "stealth" feature compare to one that was built decades earlier... its sad to see technology stagnant.

but as stealth technology improves... so will radar technology...its a cycle thingy...

ultimately... it boils down to who have the money... to keep raising the stake in this neverending competition since the days man invented the spear and the shield.

There is such a thing called common sense and normal physics.

Barring any kind of top secret technology that is light years ahead of our current understanding of stealth, there is no way our Formidable will have vastly improved strealth over the Lafayette barring major changes in it's hull geometry and what have you not. It's just simple physics, and at the end of the day seems to me like wishful thinking.

It's like assuming that our F-15SG will have an vastly improved RCS over the F-15Cs that the USAF uses.

Ultimately the fact remains that despite the "stealth" label thrown around in the media these days, the media remains undecerning about being clear on what is "signature-managed" and what is truly stealth. Our FFS falls better under being called "signature-managed", as in it's "stealth" is more of something to help it reduce its vulnerability then actually be used in an offensive manner.

Shotgun SG

Modern EW can pick up signals from a radiating radar. However, new frequency agile radar lowers the risk of such detection, as well providing a quicker scan rate. The Formidable class can remain a low profile if it so chooses to.

As for the RCS, the only numbers I have doubts in is the "modern fighters" capable of scanning 300-400km... even with a modern radar like the APG-79. So far, I haven't found any publish numbers on its sea-surface search range.

38 SG

frequency agile only prevents your radar being jammed, but no help prevent being detected.

quicker scan rate is achieved by the faster spin of radar atenna of naval vessel, that's why in a highly alerted situation, the naval vessel no only need to light up slow spin main search radar, but also the fast spin fire control radar for higher update rate. this is very important to give enough early warning and information of any possilbe sea skimming anti-ship missiles.

As for 300-400kms detection range of a modern fighter towards a big surface target, look no further, guess who equips the Su30Mk which has the capability:

http://www.globalsecurity.org/military/world/russia/su-30mk.htm

compared with the predecessor, the Su-30 MK avionics suite features a number of advanced components, including: integrated radar sighting system capable of detecting and tracking up to 15 air targets, while simultaneously attacking four of them; integrated optronic sighting-and-navigation system with a laser gyro navigation system; helmet-mounted displays, head-up-display, multi-function colour LCDs with image mixing capability; GPS system (GLONASS/NAVSTAR compatible).

The powerful general-purpose phased-array radar (featuring a 20-m resolution) ensures detection of large sea-surface targets at a distance of up to 400 km, and small-size ones - at a distance of up to 120 km. In preliminary long-range aiming mode, the radar locks on the target automatically, with co-ordinates transferred into the navigation system. Then the radar is switched-off and the aircraft flies toward the target in radar-silenced mode. At near-maximum range of weapon employment, aiming means are engaged to update targeting data, and weapon system is employed against the target. Short time of radar illumination ensures concealed approach of the aircraft to the target, thus contributing to the mission success.

Shotgun SG

Reccommended reading: http://en.wikipedia.org/wiki/Low_probability_of_intercept

Phased Array Radar or AESAs provides quick scan rates that its much harder for EW equipment to detect.

This is especially a problem when we try to run against S-300 sites. Chances, it will shoot us before we even pick it up on the RWR.

As for the 400km sea-surface scan, it looks like we need to look at the small-sized category when considering the Formidable class of vessels. With that, the detection range is reduced to 120km. With the 13% detection range reduction you said, thats reduced to 104km before the ship appears as a fishing boat (Heh, don't quote these numbers, just the idea). Depending on weather and sea-state, detection ranges maybe further reduced.

I think 120km is not bad for a ship like the Formidable. Considering that at that range, it might still appear to be an insignificant fishing boat.

Btw, 120km for small vessels for the Su-30MK isn't pretty impressive. I think the Viper can do that with the current APG-68 v5/v7

SingaporeTyrannosaur SG

I think you are adding one more layer to it.

Formidable APPEARS to radar as a small ship, that was already it's bonus. You should not figure in the 13% range reduction.

Of course, this is the optimistic lionnoisy assumption that Formidable only has 1/10 RCS of what is expected of it's 3200 ton displacement, but other more conservative estimates place it an estimate that it appears much larger then that, which I actually end to believe more.

In any case it does help to hide our frigate, but it does not make it below notice. This RCS reduction means that our Formidable appears on radar more like our 500 ton PVs or 600 ton Corvettes, which helps somewhat but it probably aids in making the enemy underestimate the ship then actually hide it.

tripwire SG

just cannot understand the constant ranting over the weight of the formidable vis-a-vis its RCS.

our formidable is made of steel... which greatly increase its weight to 3200ton...

ships of similar size (similar dimensions) would weigh just above 2000ton if made of aluminium.

if by someone's definition... a 3200 ton appears as 500 to 600 ton PVs... how about a 2000+ ton frigate with RCS reduction technology? 200 ton?

SingaporeTyrannosaur SG

just cannot understand the constant ranting over the weight of the formidable vis-a-vis its RCS.

our formidable is made of steel... which greatly increase its weight to 3200ton...

ships of similar size (similar dimensions) would weigh just above 2000ton if made of aluminium.

if by someone's definition... a 3200 ton appears as 500 to 600 ton PVs... how about a 2000+ ton frigate with RCS reduction technology? 200 ton?

Seems like splitting hairs I am drawing up a rough picture here in the end.

But I think you are somewhat mistaken. I am not drawing up a direct relation between displacement and RCS, but pointing out that at such sizes, you start to get an expected RCSes for their displacement and hence it is often used as a description of RCS reduction. RCS as always, is dependent on too many other things and differ from class to class as well as design.

If you are above 2000-400tons for a monohull ship, steel, aluminum or composite you will be a ship over a hundred meters, but almost certainly under 150 meters in length. This of course is affected predicitability lends a VERY rough guides.

You are giving too much credit to the use of materials drastically changing the displacement of the ship. Ultimately displacement is also affected by how thick you cut the materials, as well as the internal design of the ship. Materials of the superstructure is just one thing.

For example, the Type 21 frigate is made out of aluminium, and measures in at 109m, but it still displaces 2860 tons. But you can go all nuts like the Russians and make a (very optimistic sounding) 2000 ton ship by really going all mad on the weight cutting for their frigates, but they still used steel and the like.

The length and size of the La Fayette (125m, 3200 t) and the Formidable (114m, 3200 t) is not that much different. You are just talking a mere 11 meter reduction in length for an over 100 meter ship for the same displacement despite the La Fayette making use of a lot of weight-saving materials to give more size-for-displacement. Not enough to really throw off any drastic displacement measurements.

Hence if you want to be more precise, you can use length and size, but at "frigate" size as we are talking about the reduction indeed will still be pretty expected.

Anyway I can't understand what the whoo-ha over our "stealth" is, it was orginally advertised as "signature-reduced" as opposed to actual idea of stealth as we would like it. Maybe more "stealthy" then the La Fayette by virtue of it's marginally smaller size and enclosed sensor mast. But at the end of the day it's an optimization of design and not a new one.

The difference between our "stealth" and true "stealth" could be said to be the difference between the B-1B Lancer and the B-2 Spirit. One is "signature-reduced" while the other is truly using stealth as a signficant part of it's game plan. I am not sure how optimistic about our "stealth" we ought to be.

SingaporeTyrannosaur SG

But the point remains is that the Formidable is a ship of conventional structural layout, displacement and size of it's expected class, so barring some really secret and advanced technology it's not going to vanish from enemy radar or be picked up only when it's within 10 nm or something like that. It's signature reduction is helpful, no doubt, bout as I said not something to lionnoisy over.

tripwire SG

its not the weight... its not the length... nor isit the steel composition that determines the RCS of our ship.

the B-2 bomber at max T-O weighs more then the B-1.

the B-2 has a wing area more then twice the B-1.

yet... its recognized or at least accepted that the B-2 has a RCS much much smaller then B-1.

clearly... wat determines "stealth" is the design and the technology involved... rather then size and weight.

the lafayette is at best a distant substitute marker when compared to the formidable... as it neither uses the same system, electronic, weapon, radar and others... nor are the top structures anyway near identical.

but i dont profess to be an expert in this stealth features... but looking from a layman's POV, it appears to the mundane eyes of mine that the DSTA and DSO together with our navy and the french really took alot of effort into designing this ship for watever purpose it was suppose to serve.

SingaporeTyrannosaur SG

its not the weight... its not the length... nor isit the steel composition that determines the RCS of our ship.

the B-2 bomber at max T-O weighs more then the B-1.

the B-2 has a wing area more then twice the B-1.

yet... its recognized or at least accepted that the B-2 has a RCS much much smaller then B-1.

clearly... wat determines "stealth" is the design and the technology involved... rather then size and weight.

Exactly the B-2 is an example of stealth-directed design while the B-1 is a signature-reduced design. We can see the difference here.

The B-2 went to the extreme and departed with as many conventional notions of what would make an aircraft as much as possible while the B-1 was still a more traditional approach to the bomber. My point is, as far as conventional surface combatant designs go our Formidable is closer to a B-1 then a B-2.

The point is, our Formidable is NOT a stealth-directed design (ie. the main point of Formidable is to stay hidden), it is a signature-reduced design akin to the B-1. It can still be detected at rather practical ranges.

Well, as I said we can only work we what we know, anything else is just hand-waving and speculation- not that ALL speculation is bad but there is a difference between an intelligent guess and wishful thinking.

I believe the shape of the ship plays prehaps the largest role in RCS, followed by materials and the like.

AFAIK, the laws of physics cannot be broken, that means that things like size and surface area will matter when it comes to figuring out RCS. What this means is that barring some Star-Trek cloaking field a 3,200 ton ship will certainly have a lot more area to bounce back radar then a smaller ship. The design of the ship attempts to get around this rule, but at the end of the day it's more of working with what you have to bend the rules then actually breaking them.

So barring some really radical shape changes and hull designs (ala. Sea Shadow), we can more or less make a ballpark guess that this ship isn't going to totally vanish of radar of be only picked up very close.

And of course there are other things to consider as well, such as it's own EM emissions (LPI or not) to factor in.

But if anything that's prehaps a good limitiation of technology, especially in our case- it would be money. DSTA and the DSO are not the top of their field in this region, though they did do a more-then-competent job for the Formidable. But it is in my opinion that we shouldn't go all Iranian on it- that is imagine fantastic abilities for each and every new stuff we come up with. And AFAIK this isn't exactly on the scale of technology and complexity as the Yank next gen destroyer project. And I don't think the RSN's specs called for a frigate that would totally drop all radar.

Ultimately it's true. We don't know enough and I am quite sure the RSN isn't going to advertise the actual RCS of its ship. But it is my humble opinion that the stealth is more of a useful feature then a fight-winner in this case. Prehaps blend in with littorial traffic? Get a Harpoon off at max range while the enemy is still having trouble figuring out who you are? Maybe. But total B-2 styled surprise is best done by our subs.

Shotgun SG

I think you are adding one more layer to it.

Formidable APPEARS to radar as a small ship, that was already it's bonus. You should not figure in the 13% range reduction.

Oh no, I didn't come up with the 13% reduction. That number was what 38[] gave in his previous post. I'm just not challenging it cos I'm not an expert in stealth nor am I confident of my mathematics.

SGtrex, I guess when you say "signature-reduced", the B2 can also be considered in that category. Going that direction would only leave us with the tough option of quantifying "stealth." IE, How much signature reduction would be considered "Stealth."

IMO, Stealth is a "profile" given to a particular platform to conduct operations in a manner which cannot be easily detected. Hence, given a reduced signature profile, the Formidable class frigate CAN carryout operations in a "Stealthy" manner. Soon enough, "stealth" will become a requirement for most combat platforms, as people realise the need to reduce radar signature.

Can our frigate hide completely from view? Yes, given sufficient distance from the radar reciever. Eg, (again, numbers are just an example) if the Formidable appears as a small fishing boat at 80nmi, it might not be detected at all, at 100nmi. If I recall my concepts of stealth correctly, the closer it gets, the stronger the return signal is, and the larger the formidable will appear. However, that does not mean that the radar will return an image of the formidable as its full physical size. Even at 40nmi, 20nmi, it will STILL appear smaller than it is, depending on how well designed its "Stealth" features are.

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