Zumwalt: Stealth and Armor in Modern Naval Combat

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Senanthes
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Re: Zumwalt: Stealth and Armor in Modern Naval Combat

Post by Senanthes »

So, a lot of ground to cover regarding both preconceptions and misconceptions in this whole armored warship/battleship debate...

First off, the idea for dispersed communications, hull antennae, and radar kites. Building antennae into the deck and railing really doesn't solve anything, in terms of shock damage, since they still have to be exposed to operate (burying them in the deck armor would result in lack of function, becoming self defeating), and thus would be damaged, or destroyed, by even a near miss... The kite really isn't even a question to me. What makes it less likely that the array itself wouldn't be hit by chance? Specifically targeted? Cable sheared off? It's another unarmored item that can be shot off, in the end.

The 'hull antennae' idea is easily answered by looking at the design of ships in general... There is a reason all that gear is located at the top of the superstructure, away from highly conductive seawater. It's not that your signal would be impaired... You wouldn't get one. It would simply bleed off into the surrounding ocean, and even if you did, however unlikely it is, get a faint signal connection, any modicum of EW would render it moot.

In order to perform a gunnery mission on today's highly fluid battlefield, you will need more than a walkie-talkie and functioning guns... Unless you don't mind dropping shells on your own men, or on civilians. Radars, rangefinders and modern communications do far more than give you coordinates. They offer to-the-meter calculations for a firing solution, give a first shot hit probability that is absolutely crucial when providing fire support, and offer a networked viewpoint that is completely lacking with the bare bones approach from the 1940's... One look at the hit ratios of such guns in action without modern communications is all the proof of that concept that most anyone needs, methinks. They weren't even that good at hitting each other, and thats what they were supposed to do to start with. More sucess was achieved at lobbing shells at shore targets that couldn't move... But what about modern battlefields where the enemy is more often on the move, rarely dug in, and likely to be mechanized?

Unless he's profoundly stupid, the 'Bad Guy' isn't going to line up nice and neat for your guns. And he doesn't have to go that far inland to avoid them.

All of that said, I feel some clarification is in order regarding a few bones of contention in this thread...

First, a disclaimer... If the automatic response is 'But there will be new advances!', then the automatic answer is 'I've got a Silver Bullet for your Magic Armor.' I'm using what we have today, not what we might have twenty years from now, and history goes a long way towards explaining, by itself, that every advancement in defensive ability is temporary, and the weapon to defeat it is often both cheaper and easier to make.

That said, let's start with some basics, and the basic I will start with is what 'Semi-Armor Piercing' actually means. After doing a little digging, I found that the term actually dates back to the days of the Dreadnought and other ships like her, referring to shells that were quite capable of penetrating light to medium armor, but not the heaviest stuff out there.

It means the same thing regarding ship to ship missiles. 'Semi-armor piercing' doesn't mean it can't penetrate more than a basic hull, it merely means that the missile isn't meant to fly through more than a modest amount of shipboard armor before detonating... Now, finding absolute facts in terms of this armor defeating ability isn't easy, but I have dug up a few estimates over the last week or so that paint a picture for comparison. And I don't even have to jump to 'but it could be developed' from here.

I'll open with the AGM-84 Harpoon, the lightest of the threat missiles that this fictional warship would have to defeat. It's just about 15 feet long (4.6 meters), weighs in at 1,523 pounds (691 kilograms, with booster), and flies at a 'measly' 537 miles per hour (864 kph/ 240 meters/second). This is pretty much the standard anti ship missile of the US Navy, discounting the possibility of tossing Tomahawks at a target. The original, un-upgraded, Block I Harpoon is estimated to have a penetration of 2.7-4 inches (6.9-17.4 cm) of RHA. It is, by absolutely all definitions, an armor piercing weapon, designed to defeat light to medium shipboard armor, but not foot thick plate.

Now, upping the ante to another missile discounted as a threat (for some reason)... The SS-N-19 'Shipwreck' (otherwise known as the P-700 Granit). This is a bit of a big boy, designed by the Soviets in the 1970's to attack US carrier battle groups. It's 33 feet (10 m) long, and weighs a whopping 15,000 pounds (7,000 kg), with an estimated speed of at LEAST Mach 1.6, but an upper estimated speed of GREATER than Mach 2.5, in it's operational envelope, which is an altitude of about 30 feet above the water... And they work in swarms of 4-8, with one missile performing short 'pop-up' periods to feed targeting data to the others. Nifty, I think, for a weapon that's been in service at least 34 years. It's estimated penetration is a minimum of 7 inches of RHA... And a maximum of 10 inches of RHA. 10 inches. Nearly a foot of solid steel, and this is still classified as a 'semi-armor piercing' weapon.

So, no, 'semi-armor piercing' doesn't mean that it can't penetrate armor. On the contrary, it's meant to, just not massive amounts of it.

Now then, another thing that cropped up before is the belief that a shell from a large (16 inch) gun is a better armor piercing weapon than a ship to ship missile, even a monster like the Granit... It's time we take a close look at both devices, and how armor piercing weapons ACTUALLY become armor piercing. While we're at it, I think that getting an idea of the actual joules delivered on impact might be a thought, too.

The Mark 8 'Super Heavy' shell, fired by the Mark 7 16 inch/50 caliber (the barrel length is 50 times the diameter of the bore) weighs in at 2,700 pounds, with an optimum range of 23.4 miles, and a muzzle velocity of 2,500 ft/second (762 m/s). This is assuming a maximum charge of six 110 pound bags of powder. Assuming the weapon hits, which is far from guaranteed, the impact delivering approximately 18.28 megajoules (nearly 13.5 million ft/lbs) of energy. Due to the fact that the shells often impacted at oblique angles, they used a blunt cap sealed to the top of the actual warhead (the pointed cap you see is just the ballistic cap. It's hollow) to allow for better penetration at non-optimum angles.

By comparison, the 'semi-armor piercing' P-700, weighing in at 15,000 pounds, and flying at a minimum of 1784 ft/s (544 m/s), and a potential maximum of 2,789 ft/s (805 m/s) is going to deliver between 76.16 megajoules (nearly 56.2 million foot pounds) of impact force to a maximum of 112.7 megajoules (over 83.1 million foot pounds). At it's WORST estimates, the P-700 has more penetrating power available to do the job, plus the advantages of being able to hit at a much closer to optimum angle, and the ability to evade CIWS batteries.

Before moving on to the issues presented with the suggested armoring, it's worth noting two things... First, the shells in question are only as fast as the missiles CIWS batteries are meant to defeat, do not evade, and fly in a predictable, easily tracked arc. Pretty much anything from SeaRAM to Phalanx can track, engage, and destroy incoming weapons of this type. The system doesn't care if it's a shell or a missile, and the effects of it's delivered ordinance will be the same.

Second, the only difference between the 'armor piercing, capped' shells, and the 'semi-armor piercing' missiles is a relatively thin cap in the shell... The missiles (if they don't already. I'm not privy to everything) can use a more efficient conical penetrator (which tends to scoop and skip off at odd angles, hence why the shells use a blunt cap) with minimal modification to the airframe. Remember... The estimates are for the current, semi-armor piercing, weapons. Just imagine what a simple modification could do.

All of this brings me to the question... 'What does Sen think it takes to stop a missile?'. The answer is, more than four inches of plate and a layer of uber-goo. The relatively puny Harpoon, in it's earliest incarnation (I've heard anecdotal recounts that the air launched SLAM-ER variant and the Block II may have twice the penetration), MIGHT be stopped by those plates, if it's only capable of penetrating under three inches... And you've got even odds at it's maximum estimates. That doesn't sound good, and it gets much worse with capital ship killers like the Granit (And it's brother the P-800 Oniks, and cousin BraMos).

So, at four inches, you've got an even chance of stopping a Harpoon, but none at all of stopping the big Russian weapons. So, that leaves a choice... Either we go to 8 inches equivalent, and reassure ourselves that these weapons couldn't POSSIBLY perform to the maximum estimates... Or we acknowledge the danger, and go with the equivalent of 11 inches.

8-11 inches RHA equivalent of armor. I call that Slab, friends.

Now, as for armor composition... Let's explore ballistic steel and non-Newtonian fluids a bit. We all know what hardened steel is, which is the same animal as 'ballistic steel', which is also known as RHA (Rolled Homogeneous Armor), so we already know how much of this we need to stop a given weapon. Two two inch plates just isn't enough, unless we're cutting corners in cost. In that case, why use expensive armor on an outer layer that wont stop the weapons to start with?

Non-Newtonian fluids, more properly known as Shear Thickening Fluid in the context we're using, are fluids that react as a solid when struck. We've all heard the hype about the 'liquid body armor' that's been in testing for some time now, but there are some misconceptions about the STF, how it's used, what it is, and what it can do, that lead to ideas like this goo sandwich armor plan. So, I'm going to digress long enough to paint the whole picture...

The liquid body armor... Is Kevlar.

Thats right, it's good old, Dupont Kevlar. Now, the STF, in this case sillica suspended in ethylene glycol, does not form a fluid layer between the Kevlar layers, but is instead an immulsion. It's dhilluted in ethanol, then the Kevlar is soaked in it before being baked to boil away the ethanol, leaving the STF bonded with the fibers. The net result is that the STF assists in absorbing the shock of an impact, by lending it's properties to the Kevlar, not allowing the fibers to stretch so much. The net result is that four layers of Kevlar perform like ten. Impressive, but on it's own, the STF is nothing more than goop.

The error in using it as a stand alone layer in solid armor is twofold. First, it's still a liquid, with a finite viscosity (it only gets so 'solid' before it can do no more), and finite surface tension that doesn't even begin to approach that of solid metal. A pool filled with this stuff wouldn't stop a missile, or even a high powered rifle round, on it's own. It probably wouldn't even slow it down much before it hits the concrete bottom and blasts goop all over. Second, the outer layer of ballistic steel has no real give. It doesn't transfer the kinetic energy of impacts very well at all, and thus won't make good use of any sort of STF as a means of spreading out the impact before the weapon in question breaks through the first two inch plate, and just plows through the gooey layer underneath.

Barring flights of fancy regarding pseudo-magical substances that have the potential viscosity of steel, that leaves STF relatively pointless as a means to armor a ship... Though you COULD use the treated Kevlar. In fact, I'd recommend it.

Now, moving on to "Chobham", which seems to have become common slang for any type of composite vehicle armor lately, allow me to shed some light on how it works, and what sort of threats it is meant to defeat. Originally, this form of armor was developed at Chobham Academy, in England, hence the common use of the name. As we all know, it's a multi-layer mishmash of composite, fabric and metal meant to armor up heavy combat vehicles, such as tanks. Primarily, Chobham is intended to defeat two threats... High velocity kinetic penetrators, and HEAT rounds, neither of which are likely to be encountered by a ship, or pose much of a threat to it.

Having already discussed why HEAT warheads aren't a threat, and having already presented that you don't need any such device to defeat this armor concept, I think it's time we got off the HEAT Horse once and for all. Nobody is going to bother with an ineffective weapon, and armoring against an idealized threat is self defeating.

As for the type of kinetic penetrators I've brought up... I'm referring to the APFSDS-LRP style rounds fired by tanks, which have very little in common with an anti ship missile. Modern anti-tank rounds are, minus the casing, powder, and sabot, darts. Approximately 2-3 cm in diameter and 50-60 centimeters long, and getting both thinner and longer as time goes on. Sure, these will fly right through most any conventional armor... And much like HEAT, not really do all that much in the aftermath without an enclosed space to bounce white hot fragments around in.

Chobham armor works in two ways to defeat these threats... It breaks, and it deforms. No joke. When faced with a HEAT round, the armor layers variously ablate, crack and break, deforming the jet within the armor via said cracks and breaks, and defeating the weapon. It's similar for a kinetic round, which being a relatively light, incredibly high velocity weapon, has a tendency to shatter, bend, or deflect when it abruptly stops. Boron carbide, or other similar materials, can defeat such weapons in this way, and often wind up cracked or broken in the process, aiding in deflecting the attack off to an odd angle within the plate. This means three things... It doesn't have very good multiple-hit capability once it's damaged, losing it's protective qualities rapidly, must be backed by traditional steel plate to work effectively, and must be replaced once damaged. It can't be repaired, welded, or plugged.

What this means in more concise terms is that the armor might stop the initial strike (assuming the two ton or heavier missile doesn't overcome it's relatively brittle hardness), but will do little against a multiple hit scenario. And it's expensive. Not a very good combination for large scale use on warships, I daresay. It's just not optimized for the threats any ship would realistically face.

Which leaves us with... Steel and Kevlar. Steel is more easily repaired, replaced, and cheaper than fancy composites, and Kevlar is an amazing material when you need to protect vital areas. This seems to be the thinking of the engineers that designed the Arleigh Burke's, actually... Which, contrary to popular belief, are actually constructed of "military grade" (read RHA) steel, with 130 tons of Kevlar internal armor. Yup... It's actually built of armor grade 'ballistic' steel, like many modern combat vehicles.

So... In order to produce an armored warship... It's actually going to have to be armored well enough to meet the threats that are actually out there. There are no cheats, no miracles... As Nemo said "Nothing is new under the sun." It's either all or nothing.

Now, as much as I have enjoyed the debate regarding armor, battleships, and ideas regarding both, I feel that it has reached it's limits, in terms of existing technology, and discussion, without wandering into the realm of conjecture and wishful thinking on both sides. On that note, I thank you all, without sarcasm, for the entertaining diversion. :)

discord
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Re: Zumwalt: Stealth and Armor in Modern Naval Combat

Post by discord »

sen: i pretty much agree, with a few points of disagreement.

#1 dispersed antenna, the idea of redundancy is not exactly new, and it works.

#2 the idea of having a liquid between the steel plates is to change HOW the projectile penetrates, since the water is not compressible to go through the first plate you should need to push it inward, a movement which is stopped by the water, which in turn needs to be moved for the first to be penetrated thereby spreading out the impact...well that is the idea anyway, and it works well against HEAT too for pretty much the same reasons.

no idea how well it works though.

#3 shock damage against a solidly attached(as into something) antenna? if that breaks in such a manner the whole ship should vibrate apart, impact sure, therefor redundancy, might have misunderstood you here though.

#4 as a example, Iowa-class got 12.1 inch belt and 19.7 inch turret, heck lowest is deck armor at 7.5 inch armor.....so not impossible to armor against what you mentioned, just thinking there should be some way to make it better without just 'adding more'.

#5 CIWS stopping 16 inch shells? those are mostly a big lump of metal, how do you 'stop' them with 20mm rounds? since the detonator afaik is not a simple impact fuse but a 'we have suddenly slowed down enough' kind....just saying.

final note, strapping explosives on the outside of your armored vehicle was considered pretty crazy until someone proved otherwise.

Senanthes
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Re: Zumwalt: Stealth and Armor in Modern Naval Combat

Post by Senanthes »

1. You can only disperse so much. Those arrays are heavier and larger than you might think, and take up space and power. You have only so much space in a hull that isn't built to arbitrarily huge dimensions, and multi-hundred pound warheads cause fairly massive blasts, the shockwaves being quite able to cause damage for several hundred feet. Some backups are standard, but too many cuts into space for other vital systems, without appreciably increasing their independent survivability.
2. From non-Newtonian fluid to water now, eh? Same surface tension issue, and it won't help alter the trajectory of a heavy projectile, or one under power, with only a thin layer. Also, water adds to the issue of any kinetic impacts for the very reason you give. It doesn't compress, and is an excellent energy transfer medium (torpedo detonations). Armor needs a little give to have the effect you're going for, either by deformation or fracture, and the best combination so far has been alternating layers of "soft" steel and RHA. Unless the outer layer is boron carbide (with all the associated issues), all you're doing is giving any armor piercing weapon a target that won't deform enough before it gives way, which actually raises the odds that it will penetrate.
3. Attach an antenna to a block of armor... it's still a fragile, vulnerable piece of hardware. People have repeatedly told you that they can't be effectively armored. They're right.
4. Whether there should be or not isn't an issue. The fact is, you can't skimp and expect results, look for corners to cut, or use armor that won't defeat the real threats. Nor do you need HEAT for anything beyond it being some sort of fixation here, to defeat it. The penetration of existing 'semi-armor piercing' missiles is already a threat. Cap the warheads, and those ratings go up. So, yup... You need the sort of armor that a battleship is designed with, just like the Iowa example, for the sort of survivability you want. Also, fun fact, the bomb deck (s) arent a single layer of deck armor, but rather multiple decks that have been armored with steel and concrete as a "defense in depth" method that confines bomb hits to the upper deck in theory. Heavy, heavy method.
5. Yes. Delivered at 45 rounds per second, the 20mm tungsten tipped depleted uranium shells fired by a Phalanx will actually shred this "big bad" shell when they impact at a total of 5000 ft/second. A SeaRAM or ESSM will literally knock it out of the air with a near miss. It's just another projectile, and all that needs to happen is for it's trajectory to change. Also, at 2700 ft/sec, the shells are in flight for over a minute at long range, which is where you'll be (at best) against a faster, lighter missile boat. That's more than enough time for Aegis to lock up and knock down a full salvo, before it even becomes an issue involving CIWS batteries (which function independently of the ships fire control. So long as they have power and ammunition, they'll keep working. Neat stuff. :-) ). Just with one functioning Phalanx, at the terminal layer, which starts firing at three miles (having locked on at about five), any incoming has the potential to be hit by 270 rounds... That's more than enough to do the job by raw weight of fire... It's likely to take far less, since many will be striking the blunt penetrating cap, which isn't nearly thick enough to stop those rounds at that velocity.

As for reactive armor... This has been covered. It's heavy, maintenence intensive, and has zero multiple hit capability. Best of luck changing out those modules at sea.

All of these points have been addressed before, with the exception of #5.

In the end, I don't disagree that armor is a good thing, and I do think that roles exist for more heavily armored ships. I disagree on the methods and platform, mostly.

discord
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Re: Zumwalt: Stealth and Armor in Modern Naval Combat

Post by discord »

sen:
#1&3 i think we are talking about two different things, one is a radar system, the other is a radio emitter/receiver, a simple radio antenna could be mounted as a inlay INTO armor(with a little insulation), that was what i was talking about, for communicating with a external sensor(drone), which is a way of armoring sensor systems by having multiple redundancy inside armor and launch new ones at need.

perfect? no, but seems plausible as backup.

#2 actually i started with water went to fuel storage(since some data i found pointed to diesel being better at the function) and then to non newtonian wondering if that would improve effectiveness of the idea.
or it might by shockwave increase the cross section of the penetration, improving armor efficiency, do not know enough about fluid mechanics to answer it though, as i said, it's an idea.

#4 still thinking there should be some way of making the 'slab' more effective without making it silly expensive, simple layering of soft and hard steel as you mentioned might do the trick though, perhaps a third layer of some kind?

#5 hmm, yes, doing the math those projectiles would be pretty nasty, but the effective range of a phalanx system is 2000m while the velocity of the target is 800m/s which gives the CIWS about 3 seconds to stop nine shells....not sure if those 20mm will do any significant damage to a 1 metric ton lump of metal though, and if not it would need 1500+ hitting rounds to impart enough kinetic energy to stop the 16 inch shell, hint a CIWS fires 75 rounds/s multiply that by 3 and you get 225, or possibly enough to deflect one shell, or it might shatter the shell and explode the burst charge at which point a single CIWS might stop a full broadside....who knows.

it does not take much to shot down a missile, nor a mortar shell, but this is something else.

did not say reactive armor is applicable in a naval setting, just that people thought the first guy to come up with it was nuts until he proved he was not, repeatedly.

bottom line, armoring is only reasonably possible on large to VERY large ships, i do not however agree that we should remove the old school legacy optical method for a big gun ship, redundancy is king after all, as well known in the armored vehicle business.

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pinheadh78
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Re: Zumwalt: Stealth and Armor in Modern Naval Combat

Post by pinheadh78 »

I'm not going to debate armor vs stealth, Senanthes and others have covered that very well. Just covering the radio and CWIS system.

I'm also exiting the thread; if you guys want to discuss the merits of an existing ship or cool new technology then I'll join back in. Peace out! :P

#1 and 3 - Wont work in a naval vessel far from shore with armor all around it. Cars radios and cell phones can get away with it because the send/receive systems are usually within a mile or line-of-site. On anything that needs to transmit on long-range communication frequencies it needs to have both length and height or be able to adjust itself to see the satellites. Putting it flush with the hull just means that it can only transmit and receive from only one side of the ship as the ship itself acts as a barrier. The radio antenna must still be exposed (outside the armor) to work at all and remember there are still constraints on length and diameter so it can be turned to the correct frequency or it wont work at all. Radar would have the same issues with blind-spots and distance.

#2 and 4: Senanthes gave some fantastic posts about impact energies, penetration depth, and practicality. He's right.

#5 - Think of the CWIS 20mm as an anti-tank gun. The small tungsten dart fired by a the 120mm gun on an Abrams tank has no trouble going clean through (in one side and out the other) of most modern MBTs. Why would the 20mm have any problem going through a 16in shell that is much simpler and not designed to resist (like a tank is) the impact? The impact energy alone would work and the missile-based systems... Senanthes is right on those. The range on a Phalanx is allot more than 2000m, that number is just for the press. Besides, there are bigger 30mm and 40mm CWIS systems out there.

discord
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Re: Zumwalt: Stealth and Armor in Modern Naval Combat

Post by discord »

pinhead: starting think people are dissing my ideas just cause it is me putting them forward.

#1 & 3 on the antenna, never said radar, never said equal to primary coms, i said backup to communicate with sensor drones(useful if the ship has sustained multiple hits and sensors and coms are down due to damage, both are targets for Anti Radiation targeting, and likely to get hit by missiles), those drones can be high up, them being a hundred km away(not that you would want them that far away in most cases.) can still be 'line of sight' so yes, it could bloody well work.
and what does the armor change? the antenna i proposed is ON the armor, multiple redundant inlay antennas on each facing means that yes, it COULD receive and send from all sides, question is if the metal armor would interfere or not, if so you would need have some distance and my first thought on this was effectively inside the railing, which easily could be non magnetic.

#2 & 4: so you are saying there has been no improvement in armor science since WW2 and thicker slabs of simple RHA steel is the most effective armoring method ever? i don't believe so.
and i agree with sen's arguments, i did not have any good numbers on penetration ability of those weapons, he found them, which leads to needing pretty thick armor, and thereby only applicable for really big ships.
although i still think layered less thick armor(the 2 inch everywhere idea) could work pretty well.

#5 those 20mm rounds(actually a 15mm sabot, but that is nitpicking) would have plenty of kinetic energy, yes, and penetration ability, yes, both enhanced by combined velocities, yes, but this is 183cm(six feet, which incidentally is the same length as my own not so humble self) of bleeping steel, 1830mm(which incidentally is about twice the RHA equivalent of the M1 turret with SEP upgrade.) although perhaps not RHA it is however hardened steel, at least for the AP version.
note, the M61(which is the gun the phalanx CIWS is based on)with best AP rounds defeats 12.5mm RHA, double that for the sub caliber penetrator used, double it again due to non perfect armoring, and a third time for meeting velocities, and you are still about 1730mm short of going straight through, at this point you might understand my claim of uncertainty about how much damage the itty bitty round will do.

heck, a M1 Abrams main gun might have trouble going 'through' under those circumstances, since the shell in questing is quite angled to boot, making a glancing shot probable.

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pinheadh78
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Re: Zumwalt: Stealth and Armor in Modern Naval Combat

Post by pinheadh78 »

Hi Discord
Sorry if you got that impression and a double apology if I contributed to it. But the discussion has whittled down from many people in the beginning to just a few people with three of them the most active so its less of a debate and more of... well.. something else.

If you guys want to discuss new technologies or current ships and the like (like the 'real aerospace thread') then by all means lets go!

Maybe time for a new thread? Something like "The real navy thread?" :D

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Re: Zumwalt: Stealth and Armor in Modern Naval Combat

Post by Senanthes »

Whelp... When a debate feels like an attack, it's time to end the debate. For the record, such isn't my intent. I simply answer what's tossed out with the facts I dig up, and conclusions drawn from them. Over the course of my research, I've had a grand time in that I've learned a lot about subjects I was only peripherally aware of, so I can leave it here on a high note. See you all around!

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Re: Zumwalt: Stealth and Armor in Modern Naval Combat

Post by discord »

was fun talking about it, would have loved to test out these ideas and see what happened, i still think that steel/water/more steel thing would improve armoring more than same weight in only steel, would cost in volume though, but big ships have plenty of that.

edit
assuming a 2 inch steel/12 inch water/6 inch steel or so, my guess would be a impact hard enough would rebound and knock the first plate outward, since the water has to expand, and that is the direction of least resistance.....just thinking.
/edit

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Re: Zumwalt: Stealth and Armor in Modern Naval Combat

Post by Senanthes »

discord wrote:was fun talking about it, would have loved to test out these ideas and see what happened, i still think that steel/water/more steel thing would improve armoring more than same weight in only steel, would cost in volume though, but big ships have plenty of that.

edit
assuming a 2 inch steel/12 inch water/6 inch steel or so, my guess would be a impact hard enough would rebound and knock the first plate outward, since the water has to expand, and that is the direction of least resistance.....just thinking.
/edit
I was considering a possible effective armor scheme myself a bit near the end of this...

An eight inch "drop in" module, not unlike the way the older Challenger 1 tanks were designed. The armor modules fit into pockets in the outer hull, bolted in at the top to the structure with attachment points for cables/cranes at the top of the case for (relatively) easy replacement. The outer layer is two inches thick, comprised of fist sized blocks of RHA, set in foam rubber with an edge out, creating a surface where a "straight shot" is relatively impossible to achieve. It won't stop anything beyond relatively small weapons, but it will deform virtually anything that hits it. The second layer is solid boron carbide, four inches thick, mounted in blocks about a foot long, meant to absorb kinetic impacts. The third is a two inch layer of "soft" steel or aluminum to which the boron carbide is bonded. I'd use aluminum, since the purpose of this layer is actually to compress, flex and bend, and weight is a factor. You'd want kevlar spall lining behind the modules, and they wouldn't have great multiple hit capacity, but if each was two to four feet wide, you'd likely have enough protection for at least one major engagement with effective Aegis and CIWS taking their toll on the incoming.

Thinking about it, the modules could be produced in various configurations that would allow them to be bolted to the outside of the superstructure and the deck as well. All you have to do is produce "cases" of differing size and mounting configuration. If they're light enough, they could be replaced at sea by a fleet tender... For more variety, "double proof" and "half-proof" modules (thicker or thinner) could also be used on various classes of ship. So... You've got the 'drop-in's' on the sides, bolt on modules for the superstructure, and perhaps deck plate modules mounted under a removable steel grating serving as the ships deck.

The cons are simple, and really haven't disappeared, merely been minimized in some regards. They'd still be fairly heavy, though not as much as using raw steel or water, and EXPENSIVE. Boron carbide is very expensive stuff. Also, same problems as before regarding composite armor, somewhat offset by the design. You'd have to replace them each time they were hit, but the overall module could be sent home, mostly salvaged, and reworked, helping to defray cost. It's the most effective scheme I can think of off the top of my head, and could be applied to just about any hull as an add-on module.

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Re: Zumwalt: Stealth and Armor in Modern Naval Combat

Post by discord »

sen: first weakness i can see is sub-surface armoring, can't be used for that at all...second, you need pretty sturdy method of holding'em in place, those drop ins are gonna weigh a fuckton.

but the basic idea of a cell based relatively easy replacement armor seems like a pretty good direction to go.

interlocking hexagonal cells(approx. 30cm-1m in diameter) with small towel hangers underneath each to sustain the weight, smaller deformation area damaged by a hit, pretty high probability the cell would go into the drink due to a hit though.
trouble though, the interlocking part makes quick repairs difficult, it improves the ability to hold it together significantly, spring loaded click in? nah, structurally unsound, would create serious weakness, might be worth it for easier repairs though.
glue? would need to be easily dissolved, which creates problems again.
electromagnetic? not a bad idea, might work as a halfway decent decoy system, but that also means it would have EM noise like....well stealth would be way out the question.
slip in attachment? using insert keyhole attachment, might work pretty well, but still has the problem of needing to move the above 'hexes' to insert....coming to the conclusion that some sort of spring loaded click in might be best for easy replacement, but it has issues.
might be better to go with squares even if that again reduces structural integrity just to make it easier to remove the cells above.

yup, squares, interlocking, keyhole and bolted in place, major issues, needs to move all above cells to exchange one even if it is fewer compared to hexes, slightly lowered ability to round things compared to hexes, too bad, hexes would have been much sexier.

or the simple method, just add more steel.

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