Type 055 DDG Large Destroyer Thread


Tam

Colonel
Registered Member
Let's stick to the original point of contention. This is what you said:

I pointed out how that doesn't apply to missiles with optical guidance. Whether and/or when optical or radio is better is besides the point. It's clear to everyone that the NSM/JSM/LRASM/Penguin/SLAM-ER(-ATA) will not aim for the highest RCS spot, nor the ECM. I think it should also be clear that they are capable and dangerous missiles.

NSM and LRASM can be programmed to impact pretty much any point on a ship, the funnel included. I wouldn't be surprised if SLAM-ER has a similar capability.


What does "almost all" and "modern and capable" mean? How many exceptions am I allowed to find for that to still be true?

Here's a video of a NSM (a modern and capable missile?) test, where the missile impacts the superstructure:

You got an old ship where the superstructure is full of squared corners that will generate the highest RCS return. It can also target the superstructure because the sunlight has left the metal structure hot, making it look bright to a thermal camera.

NSM and LRASM are only programmed to hit a ship, not parts of. They use IIR to recognize the outline of a ship, not necessarily parts of a ship. If you want to program to hit parts of a ship, your missile database would exponentially explode in the sheer number of entries, and the time to query all these items would also take much much longer. Even if you did, the funnel is a bad choice for a target. An armor piercing missile can potentially just pass through the funnel when you want to sink the ship, not slow it down. Opening up the funnel isn't going to stop the ship.

There is a difference between IR guidance and IIR. IR guidance is heat seeking. These are missiles that will go after the hottest spot of the ship. IIR will identify the outline of a target by infrared camera, and match that to a database. The problem of both is the same countermeasures you use with aircraft. Flares can blind the camera and smoke will distort the ship outline.

Its not as if the 055 doesn't have layers of defense. Passives have long been used by navies for OTH targeting, only this time, with LRASM you are trying to use passives as a midcourse correction, which is also what some Russian missiles like Granit has used before. Traditionally, EMCON makes fleets difficult to target via OTH passive, and to add to that, if you have AESAs and solid state radars, you have LPI along with frequency agiles combined with pseudorandoms. To pull these signals apart from noise, you would need a server farm. Against thermal, you have management of your thermal contrast, hence the use of cooled funnels. Thermals are also more weather sensitive, water vapor does a good job of absorbing infrared, and you can get into a weather situation where both optical and thermal ranges are drastically cut. These two literally depend on their fair weather friendship, just as bad as microwave atmospheric ducting that OTH passives depend on.

The use of passives, IR and optics only serve to prevent the missile from being detected by ESM, and to be countered by ECM. It doesn't stop them from being targeted by an active radar, and have the missile blown away by gun or missile CIWS.

If your radar has detected and tracked the missile, but your ESM failed to receive any radar waveform from it, you can conclude that the antiship missile is a passive using thermal or optical in terminal, and your defenses can act on that assumption too.
 
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nlalyst

Junior Member
Registered Member
NSM and LRASM are only programmed to hit a ship, not parts of. They use IIR to recognize the outline of a ship, not necessarily parts of a ship. If you want to program to hit parts of a ship, your missile database would exponentially explode in the sheer number of entries, and the time to query all these items would also take much much longer.
For starters, these missiles have autonomous target recognition (ATR). This requires a database and neural network algorithms. Second, the selection of a precise aim point is a declared capability of the NSM.

From:
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nsm_1.png
From
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From a YT video, basically paraphrasing the information from the brochures above.
Terminal accuracy of the NSM is said to be less than two feet from the aim point to the impact point, so specific systems and areas on a ship can be incorporated into these attack plans to achieve desired disabling results. Another selling point of the NSM is its ability to recognize a ship’s class through the seeker. This ability is called autonomous target recognition (ATR). It allows the missile to engage the correct aim point for maximum damage and provide intelligence to the launching ship.

Even if you did, the funnel is a bad choice for a target. An armor piercing missile can potentially just pass through the funnel when you want to sink the ship, not slow it down. Opening up the funnel isn't going to stop the ship.
Now this is the sort of counter argument I was expecting. And I would agree, that from a horizontal flight profile it would be difficult to ensure that most of the destructive force is delivered on that kind of target. A programmable fuse with proximity detection might be able to utilize most of the HE warhead potential, if not the missile body. Debris ending up in the GT is a strong possibility. A plunging trajectory would be superior, if available.
There is a difference between IR guidance and IIR ...
That's very interesting, but perhaps something we can continue in the missile guidance thread?
 
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Tam

Colonel
Registered Member
For starters, these missiles have autonomous target recognition (ATR). This requires a database and neural network algorithms. Second, the selection of a precise aim point is a declared capability of the NSM.

From:
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View attachment 70213
From
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View attachment 70214

From a YT video, basically paraphrasing the information from the brochures above.



Now this is the sort of counter argument I was expecting. And I would agree, that from a horizontal flight profile it would be difficult to ensure that most of the destructive force is delivered on that kind of target. A programmable fuse with proximity detection might be able to utilize most of the HE warhead potential, if not the missile body. Debris ending up in the GT is a strong possibility. A plunging trajectory would be superior, if available.

That's very interesting, but perhaps something we can continue in the missile guidance thread?


IIR works on outline contrast. Parts of a ship don't show up well as outline contrast. If you have a ship outline, aim point selection would simply be to aim at the hull of the ship's outline.

best-hd-military-navy-ship-icon-outline-style-white-background-design.jpg

With digital imaging, the image is broken into pixels and the computer compares the contrast between the pixels. To make a long story short, you identify the ship based on its outline defined in a highly pixelated image. The purpose of aim point selection is to choose the point of the ship that will create as much damage to the ship as possible, and it is to make sure you hit the hull and the criticals. To aim at the superstructure, and risk the missile flying through it, is a fail, and the point of the feature is to avoid this.

Maximum damage isn't done by hitting the funnel, and with the 055 its not likely the GTs are directly below the funnel, but ducts are angled towards it. In addition to that, the actual funnels does not occupy the entire structure, only a part of it. The funnel are walled by an outer structure that is vented, where outside air cools the funnels and reduces the thermal contrast.


EYETIcoXkAwg9D2.jpg


As for the funnel ducts, they can be angled, like this fan drawing so the GTs are not directly underneath the funnels.

3_Type_055_Destroyer.jpg


Why do you not separate the funnels even further like in the Burke? One answer, RCS reduction.

Gaps in the ship is where the radio waves bounce back and forth, like between the two funnels, and between the superstructure and the first funnel.


71d704a72237b809a67a08e65437dd7e.jpg

The less complicated you are, the lower you can take your RCS. This is why this ship looks like this. The funnels and the superstructure is integrated into one mass.

thumb2-uss-zumwalt-ddg-1000-guided-missile-destroyer-us-navy-zumwalt-class-destroyer.jpg


You go eliminate the gapping between the two funnels and the funnel between the superstructure as a way of RCS reduction.


51-pFaxOqOL._AC_SX425_.jpg

Illustration on this PDF at page 9 shows the IR suppression of the funnels.

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Bltizo

Lieutenant General
Staff member
Super Moderator
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My concern was really about the funnel spacing in my initial post. It was only after @ougoah insisted that missiles don't aim at smokestacks that I pointed out that funnel spacing is a proxy for MER spacing. I find it very difficult to discuss the original question when all the follow up arguments were essentially that it's a pointless concern because missiles don't aim at smoke stacks. Sorry, but I would really like to settle the funnel question first.

So you agree that larger separation of prime movers in general means better survivability? How about the smoke stacks? Does it matter or not?

If true, and the CCGs are the equipment in the in-between MERs compartment as shown in the CCTV illustrations, doesn't that make damage to that compartment potentially catastrophic as all 4 prime movers are tightly coupled there?

Yes, of course, there are design trade-offs. But that wasn't my concern/question. I pointed out that for its size, the Type 055 has main engine funnels unusually close to each other. I enumerated and measured 6 other combatants to demonstrate my point.

If I can rephrase: is the small spacing of funnels a liability or not when hit in that location? If it is, than it's a weak point. There could be other weak points (like the CCG compartment), I am not denying that. It might make more sense to aim at those other weak points. I am not denying that either. But one item at a time, please.

I have two main points as summaries of my replies.

1. Your original post should never have been about funnel spacing, but should have been about the location of the prime movers/MERs. On some ships the location of the funnels are a proxy of the prime movers/MERs. On some ships they are not. By making such a confident proclamation about how the funnel locations of the 055 are supposedly such an inherent and obvious detriment to its survivability rather than asking a nuanced question about where 055's prime movers/MERs are, makes you look unreasonable and silly.
So no, the funnels on a ship don't really matter -- you should be talking about the location of the prime movers/MERs instead.
A hit in the funnel doesn't necessarily mean the prime movers or MERs are compromised.

2. "Better" survivability is all relative. The configuration of 055's main engine room is actually not that dissimilar to some other more modern warships like Type 26, FREMM, F125, and even Zumwalt to a degree. The benefit of having a MER/prime mover set up closer together is that it is much more space efficient. The detriment is that it is more susceptible to damage if the damage is just in the right location. The extent to which the benefits and risks outweigh each other depends on the rest of the ship.



Your original question and post was barking up the wrong tree and looking at the design of a ship in a one dimensional point of view rather than looking at each ship as a whole and weighing their individual design trade offs.
It's not something that can be reduced to "one item at a time" when you're trying to make such overzealous generalizing statements.
 

Tam

Colonel
Registered Member
Would be interesting to know what 108's name would be. The number of names might be running out. My two bets:

Zhuhai. This is after the retirement of Type 051 no. 166 Zhuhai. So that name is now available, although it does have the potential of ending up with a 052D new batch.

Fushun. China's first four destroyers based on ex-Soviet Gnevny class were Anshan, Fushun, Changchun and Taiyuan. So three are taken, which leaves you with Fushun.
 

by78

Brigadier
Sailing out of Dalian...

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