Do we know who was the individual who came up with the idea for the wooden fins for the Torpedoes used at Pearl Harbour? Also I know I asked the question some time ago but I can't find the Drydock in question again, so could you go over how the fin's worked on the Torpedoes?
What were some absolutely crazy ideas for destroyers post WW1? We do know some crazy battleship ideas like the Tillman designs or cruiser designs. But was there any weird, unusual, bizarre or even ridiculous destroyer designs? Like a destroyer with 10 main guns maybe? Or was the lack of said designs because you could only go so far with the destroyer designs themselves before they simply became light cruisers?
Drach How would battleship/cruiser scale Sabot (apds) (apfsds) or Heatfs rounds work, and if they were employed how effective would they be against ships? Maybe something like apheds like the Maus used?
As a mechanical engineer, I cannot overstate how much I appreciate this level of detail in discussing the design of, well, anything. This content is absolutely top-notch.
Fritz X only worked a few times because a) the guidance system was primitive and easily jammed, b) It required a very skilled operator to work at any real range, and c) Flying low and straight in a war zone is a bad idea. I always wonder what would have happened if Project Pigeon had been considered and developed prior to WW2.
Not long ago I had this "discussion", where I stated that Littorios had All or Nothing scheme and everyone else "looked" at me like I was alien, I then thought that I got something wrong, but I could swear I heard it from one of your videos, I was searching for that video where you went a bit more in-depth about Littorio's armour, but I couldn't find it. And now I got this.
To my understanding, "all or nothing" armor schemes are not about the details such as a decapping plate. It's a philosophy of putting the maximum protection over machinery, magazines, and possibly enough of the ship's buoyancy to float and not protecting the rest of the ship with armor. My understanding, other than the Germans, all new WWII construction used 'all or nothing' as the basis of their armor schemes.
From what I'm seeing, the armor extensions toward the bow and (to a lesser extent) stern are contrary to the "all or nothing" concept. An additional 130 mm belt extending another 35 m forward from the citadel. There also seems to be 70 mm of plating enclosing the hull space above the armored citadel up to the weather deck. At a rough guess that could be 500+ tons of extra armor doing little except ensuring that the fuse on the AP shell activates correctly.
The best scale for testing this is obviously 100 cm to the meter. Now, where can I find some spare 15" Italian gun barrels and a couple dozen km of test range? ;)
I don't know where to find a 15" naval gun, but you don't need a couple km firing range. Just fire point blank. Just scale the charge of the shell to match the its velocity at a certain distance.
Thanks Drach, now you have sent me down a foamed concrete rabbit hole. I have used foamed concrete as a controlled low strength material (CLSM) for geotechnical reasons (reducing soil loads or filling annular spaces), but I certainly never considered it for ship armor. That being said, it seems almost impossible to evaluate the material today since we know nothing of it's properties contingent on manufacture of cement, type of aggregates or cementitious admixtures (fly ash), method of mixing, method of placement, quality control, etc. And we cannot compare the concrete used then with concrete with modern synthetic foaming agents. Would they have injected carbon dioxide or used aluminium powder and calcium hydroxide? Many unknowns....
Unfortunately, the cruiser and destroyer gun turret design placed the guns too close together. This had the effect of when salvoes were fired, the passage of the shells through the interfered with the shell flight of each shell. This greatly lessened their accuracy.
I would also wonder about long-term durability of the foamed concrete between those plates. Naval vessels are subject to repeated bending and flexing, which could grind and crack the concrete. If it were solid, this would be no big deal (up to a point). But foamed concrete would eventually form voids as the cellular structure breaks down. Not something that would be easy to inspect or fix.
@@RogerS1978 Yall talking like that foamed concrete has somewhere to break off and go to when its stuck in a vaccum, a confined space, boxed and packaged in steel.... Cant go anywhere. Even if it cracks to hell inside.
Depends how they installed it. If it was simply poured into a metal cavity then that would definitely be a problem. However if they took that problem into account and maybe reinforced it or had some kind of dynamic barrier then the concrete would last much longer. Though much smaller concrete boats do exist
@@alexdunphy3716 I would love to know myself, but it is well outside my field of expertise. I can't see them just rolling up and pouring wheelbarrow-loads of mix into the space between plates, because that would almost certainly result in voids. More likely, they made big slabs and laid them in place as the outer layer was built up. As to the composition, the Roman Empire knew about foamed concrete, so it is well-understood. As I understand it, you add some kind of surfactant to the mix and then whip it up. The more you whip and the faster it sets, the more air is entrained. Preferably in lots of small bubbles rather than fewer big ones. More modern versions add stuff like nylon fibre and plasticisers to the mix, but that's well beyond the state of the art for the Littorio time period.
@@RogerS1978 The Reinforced Aerated Autoclaved Concrete (RAAC) failed in those schools because it was load-bearing, which I don't think this interspace armour would be (or at least not as much). The RAAC failed because it was not fully recognised at the time of use that it doesn't stop water ingress very well, so over a period of about 30 years the reinforcing rods got rusty and failed. Although the Littorio class sopping up water like sponges over decades might have become a problem, I don't know if there was any rebar in the blocks that might have rusted over time.
"No Littorio was ever struck on its belt armor by an incoming enemy shell during the Second World War." Now, _that_ is what I call an effective armor scheme.
There was nothing wrong with the ammo. It simply had always been fired at extreme ranges and/or on smaller ships that were manuvering to not be hit (in that case, it had been amply demonstrated that it needed thousands of shells to hit something).
You'll find the RN were more concerned about Regia Marina than Kriegsmarine overall. - A huge if had always existed for what could have been if Italians had radar,
@,MorningGIOry, same here dyslexic, for me an armored Pringles tube. Keyed only to me. 😂 Plus the decaping plate plus the gap size. So I'm now totally lost, I can't keep up with the gap numbers.
With regard to the question you pose at 24:30 or so, I doubt very much that the decapping effect is linear wrt to density of the gap fill. I suspect that the cap removal is accelerated relative to the no-fill case more by the friction imposed by the filler than by its mass or density. The goal here is after all to pull the cap off of the shell body before it strikes the inner armor layer. I could imagine foamed concrete as having surprisingly good behaviors in that context. This sort of thing is extremely difficult to model because it can have extremely sensitive behaviors wrt the specifics of the materials involved. The fact that the Italian designers were doing empirical testing with actual honest-to-goodness AP shells probably means that they had a better empirical understanding of this than we today could achieve with any amount of theoretical modeling.
The Italian navy in ww2 is very interesting. A lot of italian military technology was very out of date, out of place, or had manufacturing issues like their tanks, machine guns, a lot of their air force for most of the war, even small arms. But their navy is surprisingly competitive to its opponents, considering the rest of the armed forces. They seemed to have done a good job of innovation during a time of limited budgets and somewhat dodgy business practices of fascist government and manufacturers. Their range finding alone is quite interesting.
@@FilYRU999 In a way, If Bf 109 is a BMW than Italian G.55 is a Ferrari, you want Ferrari but it's easier to buy and make BMW, they were also a bit less armed.
@FilYRU999 the prototypes were excellent, the main problem was about the massive production, the Italian industries were able to produce those good aircraft in big scale, often the air force was obligated to use outdated planes because they were easier to produce in big numbers. Over that there was even a kind monopoly/corruption of Fiat until the beginning of the war that kept it producing outdated aircraft, as the biplane cr series, cheaper and easier to produce for a company that already had the production lines ready for it. Something similar happened for the tanks ( but in this case without good prototypes😅)
@@ducadan81 Wasn't that sticking to biplanes for too long also a result of the CR.32's still decent performance in the Spanish civil war? Unfortunately (for the Italians) that was pretty much the last time biplanes could come out ahead against monoplanes.
@@tz8785not really, it was so maybe at the very beginning, but it became immediately clear that it was obsolete already in 1940 , anyway they kept on producing it until 1944. Unfortunately the Italian military equipment in general was badly influenced from big companies monopoly ( they often had strong connections with some political) . Another example is the refuse of building engines on German license for tanks and planes. Fiat and some other companies didn't want to use projects of other foreign companies ( at least in the first years of the war ) so Italian tanks often had thin armour even because the engines were to weak to carry something heavier.
It's always incredible to imagine just the sheer mass of the armor used on these things. The first battleship I had a chance to wander about was the Massachusetts. You see the huge steel tube running up to the turret, but you don't really get a sense of it until you've passed through a hatch. It's a strange thing to wrap you head around. Then when you include the fact that that armor on the Massachusetts also had stress cracks running across them caused by the recoil forces of the main gun, then you really start to go bibbledy. An other interesting bit is one of the shells the ship fired and hit another ship. The shell was recovered, I assume to study, I don't remember precisely the story we were told. But to see the front of the shell having that shaved, chipped away look, but then the rear of the shell had, at some point on it's way to making someone's day very bad, had clearly liquified. I understand the mechanics behind that outcome, but it's still an amazing experience to see the results when you're standing right there looking at it with your own eyes. That was a great place to go. Especially since there's not a lot of places you're prevented from seeing. And while you can get guided tour, you're also allowed to wander as you please. So there's no rushing you through to get the next batch of people in. So I ended up spending 8 hours in there taking pictures of just about anything I found interesting and ended up with hundreds of photos. I was kicking myself in the butt for not having brought my DSLR as the cameras in smartphones at the time were not optimal.
I wonder if foamed concrete has properties similar to perforated armor, where the micro gaps cause massive stress on the impacting projectile, which in turn causes projectiles like a kinetic APFSDS dart to break up while passing the armor plate. Maybe foam concrete could actually aid in shattering the cap through constantly shifting stress on the material.
Good thing to consider, I think it would heavily depend on the size of the empty spaces in the concrete. The reason it works well against APDS and APFSDS is because the perforations are big enough such that a large portion of the projectiles cross section isn't hitting the armor and so a perpendicular force is generated on it. I don't see how that effect could take place if there are just a bunch of tiny air bubbles in the concrete. Something that I didn't see explicitly factored in here is the effect of the concrete acting as a backing plate to support the decapping plate, which would improve its resistance and how much having to plow through the concrete itself actually contributes
@@flavortown3781yeah, different methods to achieve the same effect; torque on the projectile. Performed plates would work better against full bore shells than NERA though
Unlikely, because of its very fine geometry, APFSDS needs relatively little shear stress to break the rod up. A naval shell is so different in that regard (being only a few diameters long), I doubt there is any similarities.
I think the best way to describe it, is worst case scenario it is inefficient although still effective, also comparable to it's contemporaries and definitely not the worst armoured. Whereas in a scenario were it works it's one of the best armoured battleships ever.
In Göteborg, Sweden there's a museum ship called HMS Småland, a 1950s destroyer of 3340 tons and member of the Halland-class, the first warship in the west equipped with an anti-ship missile (the Robot 08)! You could possibly visit that one before Jylland?
As for the skirts on the Pzkfw IV my understanding is these were to destabilized Russian 14.5 mm anti-tank rifle projectiles. These tanks had only 2 cm side armor (vs 3.8 cm on a M4 Sherman). These tanks 14.5 cm was smaller than even a 37 mm anti tank, could easily hide & ambush and could penetrate 2.5 or so centimeters of armor. These tanks skirts were intended to destabilize the projectiles causing them to tumble and lose penetrative capability. As the photos shown suggest these offered little protection against late war projectiles.57mm +.
to add to this you could argue it made APHE and HEAT rounds even more effective, since the distance from the spaced plate to the armour was roughly about the same distance as the APHE's fuse timer. This would cause the APHE to fuse on the spaced plate and detonate almost as soon as it entered the tank, maximising damage.
@@goddepersonno3782The degree which it aided HEAT rounds is dependent on the weapon in question. Usually, it tends to degrade the penetration due to the fact the armor still disrupts the jet to an extent. However, just how much it does is dependent on the outer armor in the first place, and whether it prevents penetration is dependent on that, distance from the hull, and thickness of hull armor there, and of course the angle. Specifically to Shurtzen, it was somewhat effective against small diameter HEAT, some HE rounds, and heavier HEAT rounds at certain angles, but not effective against larger HEAT rounds striking at perpendicular angles. You are correct it was designed to defeat Soviet AT rifles, but it did have some effect against HEAT rounds.
@@classifiedad1 Could work against something really weak like italian 47mm HEAT, i guess. Or something like early soviet heat ammo which was absolutely atrocious.
A very thought provoking video. It seems to me that Italian scientists had carefully studied & thought this out. And then while they were trying to make it practical, other simpler people would intervene to make the goal unattainable.
Super interesting and surprisingly clear explanation Drach, bravo! May I ask, since we are on the topic of engineering, when do you think the full analisys/strengths and weaknesses evaluation of the Bismarck class will come out?
Hmm,can't be good.she was actually the greatest battleship ever if she was build close to wwI but turtleback armour,hardly going over 30kn with that kind of hp.a decent 15"inch in 4×2 turrets...when everybody and i mean everybody was going for tripple turrets and quadruple turrets...not so good(+her weight😅😅😏)
@billycaluwaerts3724 i was referring to a video that Drach mentioned he was working on, where he will explain every bit of the design of the class and do a comparison to her contemporaries... also as he stated multiple times, Bismarck was inefficient, not ineffective, she could fight any of her contemporaries on a pretty much equal footing
@@Drachinifel Man i'm really excited for that one after I heard how much in detail you were going, Bismarck is the ship that ended up rekindling my love for ships, and brought me to your channel, I guess i'll just have to keep stocking up on snacks Anyway, sorry for the rant 😅, and thanks for replying that fast Drach, see you on the next video🫡
@willghezzi "Equal footing" is a little bit charitable. Yes, the basic statistics you find on a Wikipedia page all look comparable to ships of similar vintage. But once you delve deeper, there's a massive list of smaller issues that, collectively, would put the Bismarck at a small but compounding disadvantage against any peer ship. Primarily in a sustained operation, but nevertheless influential in a single action -- as was demonstrated during its sortie.
Excellent technical analysis, as always. It makes me think that this approach was coherent with the doctrine of engaging and firing on the enemy at longer ranges (but almost immediatelty straddlling the enemy) typical of the Regia Marina. Perhaps the overall thinking behind the armor scheme incorporated this element. Well, there's a lot of work to do yet😄
Happy you are going to Denmark. I hope I have a chance to meet you, Denmark being a small country and all. If not I do hope you have an awesome trip. Also there are some museum ships in Copenhagen you should visit. They are a bit outside the timeframe covered here but they all have some good stories, one of them accidentally fired a live harpoon missile which flew 4km over the sea before hitting a tree and destroying a couple of summers houses, somehow no one was hurt except for the pride of the crew.
Thx Drachnifel for another great video. Amazing that you are going to Denmark. Fregatten Jylland (victor of the Battle of Helgoland, 1864) is well worth a visit, and so is the museum. Fregatten was, as a hulk used for years as a hostel in the harbour of Copenhagen. My father was sleeping on it on a school outing around 1953. In the 1980ies during the cold war, there was a satirical political party (they actually ran for elections), which had as its policy on the military, that we should make Fregatten Jylland combat ready. It was later very nicely restored, so I guess it is not that far from being combat ready should need arise. Given the performance of the Russian Black Sea Fleet, it might actually be able to drive of a few Russian ships in the Baltic, should need arise. I am digressing, hope for a nice European outing for you.
No. Engineering software is a supplement to real world testing, not a replacement for it. This is why the Test and Measurement industry exists, and the science of Metrology (the science of measurement and its application). In the real world, systems can exhibit non-linear behavior or even chaotic effects that won't be checked in the software (or accounted for) unless you know they can happen (usually from real world experience) and configure it accordingly. In many cases, you'll have to write your own software to handle these problems, or work extensively with the vendor to modify the software (which likely won't happen unless they have a good financial reason to do it). All software will have bugs, usually in 'corner cases' where the vendor didn't test sufficiently, or in situations where the vendor made assumptions about use that don't match what you are trying to do. Plus, there are many numerical issues that can cause problems. If you are curious Ronald Mak's book on Numerical Computing is a good introduction to the topic - but keep in mind that this is a very complex topic and people spend their entire careers specializing in it. Also, just because you have a number, even if it is computed correctly, doesn't mean you can use that number for some particular purpose. Numbers don't always mean what people think they mean, they have to be interpreted and it's easy to go astray. Another good introductory book is How to Lie with Statistics (Huff), but again this barely scratches the surface of a very complex topic. Good engineers learn how to look for and work around these issues for the particular problems they have to deal with, but that doesn't necessarily mean the techniques will be applicable to the problems you are trying to solve. For example, relatively few of the techniques developed for military sonar are applicable to medical ultrasound: the people specializing in medical ultrasound have had to develop their own techniques that match the problems they need to solve. After simulation, you still need to do testing in the real world, and that often results in going back to do more simulation, and so on. _Simulation without testing is not reliable except for very simple and well understood problems, and even then it is likely to be very limited in scope or applicability._
What I take away from this is that the decapping plate would have worked as intended if only the Italians had moved the decapping plate outward and/or the armour belt inward enough to leave a one-meter gap. As far as I can tell, most or all of this was above the waterline, so displacement would not be an issue.
Hey Drach! Nice to see you comming to Denmark! While our recent naval history is not overly impressive, go back a few hundred years and that changes right quick. If you ever feel so inclined, give us some input or good stories about the great northern war or the like.
I feel like filling the scheme with concrete would depend veary heavily on the hardness of gravel used. It is in fact eeryly similar to later developed composite schemes, which, granted were meant primarily to counter HEAT-FS at significantly smaller calibers but they still did provide weight efficient protection against kinetic penetrators.
I think it's fascinating how similar the concepts of the decapping belt and Whipple shield are. Thin outer armor then a gap to disrupt the incoming projectile, sometimes people even talk about a "stuffed" Whipple shield with aerogel or similar in the gap.
DRACH WHEN UR IN DEN HELDER AND AMSTERDAM I WILL JOIN YOU. I am a Dutch, I visited both the buffel and hr. ns. SChorpioen. I can tell you something more about those ships! and even givve you some footage ideas
This was very interesting and has some relevance to today's reactive armor. I hope that anyone trying to model this uses dynamic, not static, material properties. They can be wildly different. Things like impact strength determined by an impact hammer and high strain rate testing like Gleeble testing would be what is needed.
What amazes me is how the Italians at the time struggled to produce decent amounts of basic weapons of war like rifles, field artillery , vehicles, tanks and planes etc, but they produced and armed reasonable numbers of very much more resource and manpower intensive, very decent capital ships.
The ships were built pre-war and the large ones not replaced as they were put out of action. Guns, tanks, and fighters need constant production and replacement (and constant upgrades in the case of the tanks and planes). That's where the Italians couldn't keep up - they had decent amounts of gear to start off, but couldn't keep up with their losses and couldn't get improved models into service fast enough.
@@rupertboleyn3885 yes, but also the L3 tankettes were pre-war and they weighted 10,000 times less than Littorios. No much production also for army guns. The truth was that navy had the priority of top quality materials than army and aviation, despite being much less used. The high quality of armour was not present in army's tanks, really shameful to my mind. A lot of men died in italian tanks with brittle armour while the super-battleships were doing nothing else than float in the ports.
Was the perpendicular force generated by an angled hit factored into the calculations for distance required to dislodged the cap? I think this should make a substantial difference
Yes, that's why the a calibre-equivilant thickness drops substantially when you account for the angling of the armour and fall of shell as compared to a 90-degree perpendicular impact.
The cap also helped align the shell to more of a 90 degree angle when impacting inclined armor or when plunging at high distance. Similar solution was used in tanks in ww2 but the cap on tank shells was strictly soft and was there to align the shell and mitigate the advantage that sloped armor provided.
And strongly contributes one of my favorite things for tank shells of making the longest acronym you can that's still _technically_ feasible. I normally just settle on APCBCHEFSDS. Or Armor Piercing, Capped, Ballistic Capped, High Explosive, Fin Stabilized, Discarding Sabot. You could go with HEAT instead of HE, but that would hardly make _actual_ sense for a shell with an armor piercing cap.
@@chrisc1140 You mean as a full-calibre APHE with a cap and a ballistic cap, and its also fin stabilized? That´s quite a stretch. And where would you fit that discarding sabot? I mean, the only thing that typically uses a discarding sabot is the APFSDS, and that´s because its quite literally just a thin rod, and not a huge container with explosives inside and 2 caps sitting on its nose...
@@mnxs tbf his shell while possible to design would be pretty useless. For one fin stabilized discarding sabot shells are usually steel, tungsten carbide or depleted uranium in a solid rod of metal. They are already quite aerodynamic and self alignment would harm performance so both C and BC are gone. HE is obviously useless on a DS round since it's a small payload and the payload itself would lower the mass and penetrative performance of the metal dart. There is a reason APFSDS or HEATFS are the ones used by modern armies, its the current META, even the Brits are dropping their hesh in favor of FS shells.
@@HalIOfFamer And then you enter ukraine and everyone needs HESH and HE, and multi-purpose HEAT is kinda...shit. But on topic of shell, discarding sabo behind the main APHE? Combined ammo like this is actually possible, and should (technically) work better. Just yeeting a rod of metal is better to deal with armor tho.
26 дней назад
00:49 Drach is driving past my Hometown Emden in Germany next year ! :) Edit: The international Maritime Museum in Hamburg has a very nice collection. Particularly of small models on the top floor. In Poland Kolberg has a small military history museum with some Torpedoboot I think.
If you are interested in visiting another u-boat after the one in Bremerhaven, you could check out the U-434 in Hamburg. It's a Soviet cold-war submarine of the Tango class that was made a Museum
I agree with yourconclusion about tve restive effect if foamed concrete falling off considerably compared to solid concrete. And to compare ut to the real world, its why we vibrate concrete to get rid if bubbles, to massivaly increase concretes strength. Concrete that falls apart due to the destructive force of a shell cap hitting it and moving through it, is not what provides the resitive force to remove the cap of a shell.
On the way to Danzig you could pay a visit to the "Marine-Ehrenmal" & U 995 in Laboe, inside the Ehrenmal is a small museum which you will probaly like. Small entry fee, but open all year. More to the east in the Schifffahrtsmuseum Rostock, you find the "Capella" a ferrocement Seeleichter Type Viking build in 1944 iirc.
Always wondered how these would have fared outside the Mediterranean. Of course this was not the theatres of operation which they were designed for. One of the reasons the Allies rejected the proposal. I always marvelled at the rear turret’s placement high above the rear deck. 👍🏻🏴
@ Thank you. My father served abroad various battleships during W.W.2; Nelson, Rodney, Malaya, U.S.S.South Dakota, and Valiant. The Queen Anne Towers on the first two ships suffered blast damage initially. I don’t know if that was solved by fitting blast protection shutters. 👍🏻🏴
@@BackwardlookingThe 'solution' for Nelson & Rodney seems to have been to not fire too far abaft the beam, though I'd expect that to go by the wayside in wartime pretty quickly.
So, they could have done what was necessary by using a further ~9" of internal space per side, or 18" in total internal beam for the length of the decap and primary belt armour. Is that about it? In which case the argument comes down to the cost vs benefit, as it always does. What consequences would the loss of those 18" have had? Interesting to consider. p.s. given they were never hit on the belt, it seems they could've forgone much of the armour and had more horizontal protection 🙃🤣🤣
Awesome vid sir - love the tech specs. It just seems to me, particularly as the complexity of the systems increases, the consistency of the protection would vary much more widely even if it has the potential to stop a 15" shell you know? It might work great on one occasion but the next it might fail catastrophically.
if you need to go somewhere between bremerhaven and gdansk, i recommend peenemünde on the baltic island of rügen... they have a soviet diesel sub as museum ship and also a small missile ship... and tho it might not be the topic of your channel, the museum for rocket developement there is a must go to!
Postwar the soviet P-15 Termit (NATO codename Styx) had a HEAT warhead. Probably an attempt to allow it to penetrate BB armour, despite its subsonic speed. The warhead massed 1000 lb and given the technology of the time and the missile's 750mm diameter could probably penetrate about 750mm of steel.
There is a video on the proposed HMS Habbukuk (spelling?), the ice (well, technically Pyecrete - ice reinforced with sawdust) giant aircraft carrier. Unless it was a Drydock segment.
@@alexandermonro6768 - Guide 113, released Mar 16, 2019 ruclips.net/video/2-8ppT7TYrg/видео.html Note, the section, were it was discussed in a meeting with Roosevelt & Churchill present, were Mountbatten shot a Pykrete sample, in their presence, and the ricocheting bullet punched a hole in Admiral King's pants. The old days were truly golden ! Though, he has discussed it many times since, including some Drydock questions.
Maths with Drach. Come back next week and learn about the differential calculus involved in the making of a cappuccino. Don't forget to bring your slide rule!
Talking of decapping armour...I've read of so called "plastic armour" that was developed after Dunkirk, as operational research had discovered asphalt decks on certain ships had offered unexpected levels of protection against armour piercing machine gun rounds. Put simply a matrix of an elastic matrix is used to support extremely hard gravel. Royal Navy wasn't happy with idea of it being called armour/ armouring merchant ship, but it did see some limited use, due to how easy it could be added to ships. I'm guessing that in effect it was annother way of decaping rounds. It does appear idea got developed into certain modern tank armours. Was it ever used on capital ships?
That sounds suspiciously like composote armour as evwntually developed in tanks, which usually involves some extremely high harness material such as tungsten carbide beads in the case of T64, fiberglass in the case of T72, or highly angled martensite steel plates in Dorsetshire composite, suspended in aome sort of amorphous polymer, resin or rubber.
@egoalter1276 yeah modern composite tank armour is supposed to have it's origins with the 1940s invention of "plastic"(meaning "easily castable") armour used on merchant ships. As I said I'm surprised it didn't see use, in between times.
I don't know of WWII battleships actually hit on the belt by other battleships. In all the engagements by ships of similar size, the main point of impact seems to have been turrets.
@@neutronalchemist3241 Take a look at the paper Kirishima Damage Analysis by Robert Lundgren. Or Drach's video on Bismark and the Cameron expedition. In both cases it is known for certain that there were hits on the belt that penetrated. I don't know offhand how much damage Bismark took from the hits that penetrated the belt. In the case of Kirishima, we know from the report of her damage control officer - who survived the action - that there was some serious damage. Unless divers have taken a look, it's hard to know whether there were hits to a ship's belt that didn't penetrate the belt. Even if divers have taken a look, it may be hard to tell in the event multiple shell sizes were being fired. Ships roll and that affects whether or not shells detonate. There could very well have been hits by Bismark on Hood that were stopped by the belt and simply never reported - there were very few survivors when Hood blew up, mostly men blown into the sea when the ship exploded and young enough to survive (despite being exposed to the frigid water) long enough to be picked up. In the case of Bismark, there were likely also many hits on the belt that didn't penetrate. It is clear that both the 14 and 16 inch shells being fired at Bismark could penetrate the belt, but it may have required the ship be at an appropriate angle during a roll. One side of Bismark is buried in the sea floor, so we'll probably never know about any hits to that side. It is believed that a hit from Duke of York penetrated the belt of Scharnhorst, destroying a boiler room. Here again it's fairly likely there were hits that didn't penetrate - in a Force 8 gale the ship would have been rolling quite a bit, changing the angling of the armor from hit to hit - but I don't know one way or the other.
Love the idea of decapping plates, but more for repair than wieght savings. Easier to repair a outer "thin" plate than a thick inner belt. The huge advance in tank size guns & armor requires more research which means more money. Winners of ww2 had better things to do in 1946 than play with ship armor. Existing ships were made of spaced armor so heat and hesh don't work as they do on tanks which have 1 compartment. Hesh is interesting for better fuse at long range but HE already existed and 30k meter shots on radar control was proven too late for caring. No one running around trying to make that when missiles offered range.
Just to throw another spanner into the works - assuming aerated concrete, what would the effect of reinforcing bar (re-bar) be? Negligible on the bar reducing the KE of the projectile directly, but it could potentially provide a mechanism for energy dispersion that holds the concrete more in place as the shell passes through? Just a stray thought
You also have to consider what was the maximum plate thickness which the italian industry could reliably produce. If the main belt was already at maximum thickness then the decapping + concrete route may have been the best answer within the capabilities of italian industry.
I think the keyword here is reliability produce, I don’t disagree with some of the others that Italian industry could make 15 inch plate. But a few plates for a turret face is a far cry away from an entire armor belt. So perhaps they could make it just not in the requisite numbers.
@@thedyingtitan1247 what are you talking about, they are not few plates they were 28 plates in just 3 years, this level of production is matche only by 3 other nations, Italy could had built them with a full 350MM plate or 381MM plate, as Italy has been at the forefront of metallurgic since late 1800s, its like one of the most famous aspects of italian naval industry.
Maybe not exactly within the timescales of the channel but there are a Juliett sub and a missile attack boat/corvette at Peenemunde which is between Wilhelmshafen & Gdansk. Plus there is of course the museum where the V2 was developed. Otherwise there is Gorch Fock near that in Stralsund
Very interesting analysis! I wonder... you now calculated the worst-case situation where a shell is coming perpendicular. What about when it comes at for example 20 degrees to perpendicular? I can imagine that equal protection to regular armor at perpendicular impact is considered sufficient when at the same time you also get significant better protection at different angles. After all, in combat you'll probably are either closing the distance to your opponent when engaging a weaker opponent or increasing distance when disengaging. Even when keeping distance, you still might be laterally displaced and not having the gun bear perpendicular to the ship. The instances at which incoming fire is near perpendicular to the ship is probably quite rare compared to different angles.
Very interesting, thanks for posting. I'm wondering if the Italians were making a deliberate choice between armor thickness and speed. Such a choice might factor into the armor scheme chosen.
happy to see you are going to denmark i cant remember where but i reckomend to visit the battle of justland museum they have a really nice model of hms duke of york ive belive ohh and they have the gun of the u20 that sank lusitania and having seen frigatten jyland many many many times she is a beauti of a ship
My question would be how would they repair that armor at sea? Would they carry additional foam concrete or forms to make it on board? Or hope that another shell doesn't hit the same spot?
You don't repair heavy armour at sea. You plug the hole to keep the water out, and decide whether the damage done leaves you mission-capable or not. If not, you try to get home. This is what happened to Bismarck, though she wasn't holed through her armour, but rather in an unarmoured part of her bow. The hit didn't leave her in any danger of sinking, but slowed her and caused her the loss of fuel and to leak fuel.
No battleship, or other class of armored ships, could repair or replace its armored plates at sea. Considering that practically no battleship had been hit by another batleship on the belt in all WWII, what were the chances for it to happen twice in the same spot? there were MUCH more chances for two torpedoes to hit the same spot, but battleships had no mean to repair their torpedo defenses at sea as well.
Ships roll in the ocean due to wave forces, and since the armor moves with the ship, the angle of incline changes. A lot of time and effort has to be spent on dealing with the consequences of roll in ship design. Warships even carry an instrument called an 'inclinometer' to measure the amount of roll, which you can see on some of the warship tour videos. Plus, you never know what shells will do in the real world. They might skip off the water or the deck/structure of another ship, then hit a second target, in which case the angle of impact could be very different from theoretical predictions or predictions based on overly simple measurement. Skip bombing was a deliberate technique that was quite effective in WW2.
In Tanks composite armor has surpassed solid plates, so at least we know the Italians where on the right path, but of course who knows whether their implementation was good.
It seems to me that it had not been taken into account the main effect that hitting spaced armors at an angle has on a projectile, that's to make it tumble before hitting the main plate. That BOTH should help with decapping AND reduce the needed thickness of the main plate beyond the simply geometrical figure.
You'd think the foam would increase decapping by allowing the shell to tumble more than normal concrete. A simple UK friendly test would be using a Ramset concrete nailer. Would need equivalent samples of hardness and density.
So what happens to the ballistic cap when it hits the decapping plate? Where does the cap go, that it no longer stands between the armour and the main body of the shell?
That is irrelevant as long as it was dislodged from the main body. The cap on itself has little penetrating power since the main body of the shell provides the energy. And the main body itself (though higly energetic) is too soft to penetrate the armour.
@@vitkriklan2633 Thank you for the answer. But perhaps I worded my question poorly. So bare with me. The shell hits the decapping plate, and the cap gets dislodged. But the main body of the shell still pushes forward, and the now dislodged cap is still physically present in between the armour and the shell (I assume it did not evaporate), so where does it go? Where the physical remains of the cap go after the impact, that it no longer is in the way of the rest of the shell?
Now if a large swell was running at the time of battle, remembering that the navy of whichever country owns a fighting ship has no control of the weather, which of course includes the motion of the waves that affect the rolling of a ship particularly if the wave motion is coming from port to starboard, or in fact the other way round, then the said rolling of the ship ould nullify the angle of the armour plating, meaning that if a shell were fired from 16,000 M or about 17,000 yards and struck the side of a ship whilst the armour plating was perpendicular, meaning it was upright, then all the calculations about shell piercing would be null and void.
Analyzing the damages it received, it worked quite well, with good containment and short repairing times. The Soviets tested it in real scale against the traditional spaced system, and chose the Pugliese for the Sovetsky Soyuz class battelships. The results of their tests are available online. The Navweaps critique of a "dam mistakenly built bowing downstream" doesn't make any sense. If that's true, the traditional systems are dams with an outward 90° angle, that's even worse. Conte di Cavour and Caio Duilio at Taranto had not been hit in the Pugliese System. The torpedoes, ricocheting from the surface to the bottom of the harbor, exploded under the keel, in the worst location possible (is to purposedly achieve similar hits that magnetic fuzes had been later introduced).
It sounds to me like someone got confused during the design process and failed to account for the concrete adding weight when drawing up the construction plans then realising their mistake switched to foamed concrete after construction had started to " fix" their mistake. Either that or the foamed concrete performed well during testing with the smaller shell's and they failed to realise that using a testing regime designed for solid plate couldn't give reliable results for a composite armour. Not an obvious oversight at the time because it's very easy to fall into complacency when you have a well established reliable procedure for something and just don't consider that adding new variables might make the procedure fail.
It seems to me that the clip had not taken into account the main effect that hitting spaced armors at an angle has on a projectile, that's to make it tumble before hitting the main plate. That BOTH should help with decapping AND reduce the needed thickness of the main plate beyond the simply geometrical figure.
![Seungmin "그렇게, 천천히, 우리(As we are)" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/kAzmhLHePqU/mqdefault.jpg)
Pinned post for Q&A :)
How exaggerated was A. Iachino's statement regarding the Littorio Class' dispersion?
Do we know who was the individual who came up with the idea for the wooden fins for the Torpedoes used at Pearl Harbour?
Also I know I asked the question some time ago but I can't find the Drydock in question again, so could you go over how the fin's worked on the Torpedoes?
What were some absolutely crazy ideas for destroyers post WW1? We do know some crazy battleship ideas like the Tillman designs or cruiser designs. But was there any weird, unusual, bizarre or even ridiculous destroyer designs? Like a destroyer with 10 main guns maybe? Or was the lack of said designs because you could only go so far with the destroyer designs themselves before they simply became light cruisers?
Drach How would battleship/cruiser scale Sabot (apds) (apfsds) or Heatfs rounds work, and if they were employed how effective would they be against ships? Maybe something like apheds like the Maus used?
IIRC the Buffel was moved from Rotterdam to Hellevoetsluis.
As a mechanical engineer, I cannot overstate how much I appreciate this level of detail in discussing the design of, well, anything. This content is absolutely top-notch.
Oh ya. Drach is the best.
Also a mecheng and agreed, good technical info is so rare now
In fairness to the Italians, when she was built, nobody was thinking air delivered glide bomb (Fritz X) was gonna be a problem.
True no one thought that someone would drop a heavy explosive rocket propelled bomb that could penetrate most deck armours of the time
@UniversalChallenge4454 Not on anybody's bingo card all... probably why it worked... well except for Warspite.
@@UniversalChallenge4454Fritz X was purely glide bomb. Only pyrotechnics were flares to aid guiding.
@@Shutterbug5269 And that was only due to Warspite being too angry to die
Fritz X only worked a few times because a) the guidance system was primitive and easily jammed, b) It required a very skilled operator to work at any real range, and c) Flying low and straight in a war zone is a bad idea. I always wonder what would have happened if Project Pigeon had been considered and developed prior to WW2.
Not long ago I had this "discussion", where I stated that Littorios had All or Nothing scheme and everyone else "looked" at me like I was alien, I then thought that I got something wrong, but I could swear I heard it from one of your videos, I was searching for that video where you went a bit more in-depth about Littorio's armour, but I couldn't find it. And now I got this.
I would love to have friends where such conversations are possible ;-) My freinds would go "all or nothing????"
@jacafren5842 "Littorio? That's a restaurant, right?"
@@DoddyIshamel I mean they had to eat something, so technically it was a restaurant.
To my understanding, "all or nothing" armor schemes are not about the details such as a decapping plate. It's a philosophy of putting the maximum protection over machinery, magazines, and possibly enough of the ship's buoyancy to float and not protecting the rest of the ship with armor. My understanding, other than the Germans, all new WWII construction used 'all or nothing' as the basis of their armor schemes.
From what I'm seeing, the armor extensions toward the bow and (to a lesser extent) stern are contrary to the "all or nothing" concept. An additional 130 mm belt extending another 35 m forward from the citadel. There also seems to be 70 mm of plating enclosing the hull space above the armored citadel up to the weather deck. At a rough guess that could be 500+ tons of extra armor doing little except ensuring that the fuse on the AP shell activates correctly.
The best scale for testing this is obviously 100 cm to the meter. Now, where can I find some spare 15" Italian gun barrels and a couple dozen km of test range? ;)
Lol I read 100cm as 100mm and I thought you were building a cruiser sized littorio
Hard to say. Do you have access to any Littorio-grade foamed concrete? That seems to be the unknown variable.
But I use imperial measurements, I'll do 36" to the metre instead
I don't know where to find a 15" naval gun, but you don't need a couple km firing range.
Just fire point blank. Just scale the charge of the shell to match the its velocity at a certain distance.
dont use italian ammo, youll miss
Thanks Drach, now you have sent me down a foamed concrete rabbit hole. I have used foamed concrete as a controlled low strength material (CLSM) for geotechnical reasons (reducing soil loads or filling annular spaces), but I certainly never considered it for ship armor.
That being said, it seems almost impossible to evaluate the material today since we know nothing of it's properties contingent on manufacture of cement, type of aggregates or cementitious admixtures (fly ash), method of mixing, method of placement, quality control, etc. And we cannot compare the concrete used then with concrete with modern synthetic foaming agents. Would they have injected carbon dioxide or used aluminium powder and calcium hydroxide? Many unknowns....
Honestly, I always quite liked the Italian ships design, especially their deck paintwork.
Unfortunately, the cruiser and destroyer gun turret design placed the guns too close together. This had the effect of when salvoes were fired, the passage of the shells through the interfered with the shell flight of each shell. This greatly lessened their accuracy.
@@rvail136 Drachinifel has busted that myth a few times now- it actually was an issue with over-stabilization and production consistency issues.
The real issue about the guns being so close is it looks derpy. Made the cruisers vulnerable to emotional damage.
@@bradenhagen7977😂
@@bradenhagen7977🤣
I would also wonder about long-term durability of the foamed concrete between those plates. Naval vessels are subject to repeated bending and flexing, which could grind and crack the concrete. If it were solid, this would be no big deal (up to a point). But foamed concrete would eventually form voids as the cellular structure breaks down. Not something that would be easy to inspect or fix.
Lol UK schools are falling apart because of foamed concrete failure. Don't like its chances on a battle ship.
@@RogerS1978 Yall talking like that foamed concrete has somewhere to break off and go to when its stuck in a vaccum, a confined space, boxed and packaged in steel.... Cant go anywhere. Even if it cracks to hell inside.
Depends how they installed it. If it was simply poured into a metal cavity then that would definitely be a problem. However if they took that problem into account and maybe reinforced it or had some kind of dynamic barrier then the concrete would last much longer. Though much smaller concrete boats do exist
@@alexdunphy3716 I would love to know myself, but it is well outside my field of expertise. I can't see them just rolling up and pouring wheelbarrow-loads of mix into the space between plates, because that would almost certainly result in voids. More likely, they made big slabs and laid them in place as the outer layer was built up. As to the composition, the Roman Empire knew about foamed concrete, so it is well-understood. As I understand it, you add some kind of surfactant to the mix and then whip it up. The more you whip and the faster it sets, the more air is entrained. Preferably in lots of small bubbles rather than fewer big ones. More modern versions add stuff like nylon fibre and plasticisers to the mix, but that's well beyond the state of the art for the Littorio time period.
@@RogerS1978 The Reinforced Aerated Autoclaved Concrete (RAAC) failed in those schools because it was load-bearing, which I don't think this interspace armour would be (or at least not as much). The RAAC failed because it was not fully recognised at the time of use that it doesn't stop water ingress very well, so over a period of about 30 years the reinforcing rods got rusty and failed. Although the Littorio class sopping up water like sponges over decades might have become a problem, I don't know if there was any rebar in the blocks that might have rusted over time.
"No Littorio was ever struck on its belt armor by an incoming enemy shell during the Second World War."
Now, _that_ is what I call an effective armor scheme.
No doubt 🤭
A very underrated class of battleship. If the ammunition had lived up to the ships ability, they could have seen a real problem for the allies.
There was nothing wrong with the ammo. It simply had always been fired at extreme ranges and/or on smaller ships that were manuvering to not be hit (in that case, it had been amply demonstrated that it needed thousands of shells to hit something).
Lack of fuel was always a problem to just deploy large RM units.
You'll find the RN were more concerned about Regia Marina than Kriegsmarine overall. - A huge if had always existed for what could have been if Italians had radar,
@tristanrainey5080 true dat
If they could find fuel to sail those monsters
I'm a naval engineer and I have successfully got my two new co-workers hooked on drachinifel
I have pretty bad dyslexia and now I really want an armored Doritos bag.
@,MorningGIOry, same here dyslexic, for me an armored Pringles tube. Keyed only to me. 😂
Plus the decaping plate plus the gap size. So I'm now totally lost, I can't keep up with the gap numbers.
I know thingiverse has some models for print-in-place chain mail. You could probably modify one of those into a bag.
Seems like it'd be really hard to open when the munchies hit
Armoured dorotos bag, for when the chip theives happen to be packing naval cannons.
With regard to the question you pose at 24:30 or so, I doubt very much that the decapping effect is linear wrt to density of the gap fill. I suspect that the cap removal is accelerated relative to the no-fill case more by the friction imposed by the filler than by its mass or density. The goal here is after all to pull the cap off of the shell body before it strikes the inner armor layer. I could imagine foamed concrete as having surprisingly good behaviors in that context.
This sort of thing is extremely difficult to model because it can have extremely sensitive behaviors wrt the specifics of the materials involved. The fact that the Italian designers were doing empirical testing with actual honest-to-goodness AP shells probably means that they had a better empirical understanding of this than we today could achieve with any amount of theoretical modeling.
I am amazed at the use of foamcrete. Great discussion.
The Italian navy in ww2 is very interesting. A lot of italian military technology was very out of date, out of place, or had manufacturing issues like their tanks, machine guns, a lot of their air force for most of the war, even small arms. But their navy is surprisingly competitive to its opponents, considering the rest of the armed forces. They seemed to have done a good job of innovation during a time of limited budgets and somewhat dodgy business practices of fascist government and manufacturers. Their range finding alone is quite interesting.
Wasn’t their airforce also top of the line?
@@FilYRU999 In a way, If Bf 109 is a BMW than Italian G.55 is a Ferrari, you want Ferrari but it's easier to buy and make BMW, they were also a bit less armed.
@FilYRU999 the prototypes were excellent, the main problem was about the massive production, the Italian industries were able to produce those good aircraft in big scale, often the air force was obligated to use outdated planes because they were easier to produce in big numbers. Over that there was even a kind monopoly/corruption of Fiat until the beginning of the war that kept it producing outdated aircraft, as the biplane cr series, cheaper and easier to produce for a company that already had the production lines ready for it. Something similar happened for the tanks ( but in this case without good prototypes😅)
@@ducadan81 Wasn't that sticking to biplanes for too long also a result of the CR.32's still decent performance in the Spanish civil war? Unfortunately (for the Italians) that was pretty much the last time biplanes could come out ahead against monoplanes.
@@tz8785not really, it was so maybe at the very beginning, but it became immediately clear that it was obsolete already in 1940 , anyway they kept on producing it until 1944. Unfortunately the Italian military equipment in general was badly influenced from big companies monopoly ( they often had strong connections with some political) . Another example is the refuse of building engines on German license for tanks and planes. Fiat and some other companies didn't want to use projects of other foreign companies ( at least in the first years of the war ) so Italian tanks often had thin armour even because the engines were to weak to carry something heavier.
With respect to everything else, she was a beautiful ship.
It's always incredible to imagine just the sheer mass of the armor used on these things. The first battleship I had a chance to wander about was the Massachusetts. You see the huge steel tube running up to the turret, but you don't really get a sense of it until you've passed through a hatch. It's a strange thing to wrap you head around. Then when you include the fact that that armor on the Massachusetts also had stress cracks running across them caused by the recoil forces of the main gun, then you really start to go bibbledy. An other interesting bit is one of the shells the ship fired and hit another ship. The shell was recovered, I assume to study, I don't remember precisely the story we were told. But to see the front of the shell having that shaved, chipped away look, but then the rear of the shell had, at some point on it's way to making someone's day very bad, had clearly liquified. I understand the mechanics behind that outcome, but it's still an amazing experience to see the results when you're standing right there looking at it with your own eyes. That was a great place to go. Especially since there's not a lot of places you're prevented from seeing. And while you can get guided tour, you're also allowed to wander as you please. So there's no rushing you through to get the next batch of people in. So I ended up spending 8 hours in there taking pictures of just about anything I found interesting and ended up with hundreds of photos. I was kicking myself in the butt for not having brought my DSLR as the cameras in smartphones at the time were not optimal.
I must admit that I was thinking about why not put concrete between the two armoured plates, then you answered the question, thank you Alex
I wonder if foamed concrete has properties similar to perforated armor, where the micro gaps cause massive stress on the impacting projectile, which in turn causes projectiles like a kinetic APFSDS dart to break up while passing the armor plate. Maybe foam concrete could actually aid in shattering the cap through constantly shifting stress on the material.
Good thing to consider, I think it would heavily depend on the size of the empty spaces in the concrete. The reason it works well against APDS and APFSDS is because the perforations are big enough such that a large portion of the projectiles cross section isn't hitting the armor and so a perpendicular force is generated on it. I don't see how that effect could take place if there are just a bunch of tiny air bubbles in the concrete.
Something that I didn't see explicitly factored in here is the effect of the concrete acting as a backing plate to support the decapping plate, which would improve its resistance and how much having to plow through the concrete itself actually contributes
It's not concrete per se but that's kinda sorta how NERA armor works
@@flavortown3781yeah, different methods to achieve the same effect; torque on the projectile. Performed plates would work better against full bore shells than NERA though
Unlikely, because of its very fine geometry, APFSDS needs relatively little shear stress to break the rod up. A naval shell is so different in that regard (being only a few diameters long), I doubt there is any similarities.
I think the best way to describe it, is worst case scenario it is inefficient although still effective, also comparable to it's contemporaries and definitely not the worst armoured. Whereas in a scenario were it works it's one of the best armoured battleships ever.
In Göteborg, Sweden there's a museum ship called HMS Småland, a 1950s destroyer of 3340 tons and member of the Halland-class, the first warship in the west equipped with an anti-ship missile (the Robot 08)! You could possibly visit that one before Jylland?
Thanks for giving me some museums to visit in Denmark when I go there with my mother as part of her bucket list trip.
Damn it, now I want a danish.
@@richardm3023The benefits of being Danish: I had some this morning!
@@mnxs what kind?
@@mnxs Okay, I stopped and picked some up this morning. Strawberry with cheese, and an apple danish. Now, I truly feel alive.
As for the skirts on the Pzkfw IV my understanding is these were to destabilized Russian 14.5 mm anti-tank rifle projectiles. These tanks had only 2 cm side armor (vs 3.8 cm on a M4 Sherman). These tanks 14.5 cm was smaller than even a 37 mm anti tank, could easily hide & ambush and could penetrate 2.5 or so centimeters of armor. These tanks skirts were intended to destabilize the projectiles causing them to tumble and lose penetrative capability. As the photos shown suggest these offered little protection against late war projectiles.57mm +.
to add to this
you could argue it made APHE and HEAT rounds even more effective, since the distance from the spaced plate to the armour was roughly about the same distance as the APHE's fuse timer. This would cause the APHE to fuse on the spaced plate and detonate almost as soon as it entered the tank, maximising damage.
@@goddepersonno3782The degree which it aided HEAT rounds is dependent on the weapon in question. Usually, it tends to degrade the penetration due to the fact the armor still disrupts the jet to an extent. However, just how much it does is dependent on the outer armor in the first place, and whether it prevents penetration is dependent on that, distance from the hull, and thickness of hull armor there, and of course the angle.
Specifically to Shurtzen, it was somewhat effective against small diameter HEAT, some HE rounds, and heavier HEAT rounds at certain angles, but not effective against larger HEAT rounds striking at perpendicular angles.
You are correct it was designed to defeat Soviet AT rifles, but it did have some effect against HEAT rounds.
@@classifiedad1 Could work against something really weak like italian 47mm HEAT, i guess. Or something like early soviet heat ammo which was absolutely atrocious.
A very thought provoking video. It seems to me that Italian scientists had carefully studied & thought this out. And then while they were trying to make it practical, other simpler people would intervene to make the goal unattainable.
Listening to Drach, while sitting in my stateroom in BB55. The ambiance fits so well.
Super interesting and surprisingly clear explanation Drach, bravo!
May I ask, since we are on the topic of engineering, when do you think the full analisys/strengths and weaknesses evaluation of the Bismarck class will come out?
Hmm,can't be good.she was actually the greatest battleship ever if she was build close to wwI but turtleback armour,hardly going over 30kn with that kind of hp.a decent 15"inch in 4×2 turrets...when everybody and i mean everybody was going for tripple turrets and quadruple turrets...not so good(+her weight😅😅😏)
@billycaluwaerts3724 i was referring to a video that Drach mentioned he was working on, where he will explain every bit of the design of the class and do a comparison to her contemporaries... also as he stated multiple times, Bismarck was inefficient, not ineffective, she could fight any of her contemporaries on a pretty much equal footing
At the moment probably middle of next year. :)
@@Drachinifel Man i'm really excited for that one after I heard how much in detail you were going, Bismarck is the ship that ended up rekindling my love for ships, and brought me to your channel, I guess i'll just have to keep stocking up on snacks
Anyway, sorry for the rant 😅, and thanks for replying that fast Drach, see you on the next video🫡
@willghezzi "Equal footing" is a little bit charitable. Yes, the basic statistics you find on a Wikipedia page all look comparable to ships of similar vintage. But once you delve deeper, there's a massive list of smaller issues that, collectively, would put the Bismarck at a small but compounding disadvantage against any peer ship. Primarily in a sustained operation, but nevertheless influential in a single action -- as was demonstrated during its sortie.
Excellent technical analysis, as always. It makes me think that this approach was coherent with the doctrine of engaging and firing on the enemy at longer ranges (but almost immediatelty straddlling the enemy) typical of the Regia Marina. Perhaps the overall thinking behind the armor scheme incorporated this element. Well, there's a lot of work to do yet😄
Happy you are going to Denmark. I hope I have a chance to meet you, Denmark being a small country and all. If not I do hope you have an awesome trip. Also there are some museum ships in Copenhagen you should visit. They are a bit outside the timeframe covered here but they all have some good stories, one of them accidentally fired a live harpoon missile which flew 4km over the sea before hitting a tree and destroying a couple of summers houses, somehow no one was hurt except for the pride of the crew.
The pride of the crew was hurt, and the dignity was absolutely destroyed of the poor technician that got made the scapegoat.
I’ve been waiting for this one! DAY IMPROVED! 🎉
Anytime my all-time favorite class of battleships gets some love on Drach's channel, is a good day for sure!
Thx Drachnifel for another great video. Amazing that you are going to Denmark. Fregatten Jylland (victor of the Battle of Helgoland, 1864) is well worth a visit, and so is the museum. Fregatten was, as a hulk used for years as a hostel in the harbour of Copenhagen. My father was sleeping on it on a school outing around 1953. In the 1980ies during the cold war, there was a satirical political party (they actually ran for elections), which had as its policy on the military, that we should make Fregatten Jylland combat ready. It was later very nicely restored, so I guess it is not that far from being combat ready should need arise. Given the performance of the Russian Black Sea Fleet, it might actually be able to drive of a few Russian ships in the Baltic, should need arise. I am digressing, hope for a nice European outing for you.
Well, the engineering software exists to test it definitively. Just need someone with the inclination and the runtime availability to do it.
No. Engineering software is a supplement to real world testing, not a replacement for it. This is why the Test and Measurement industry exists, and the science of Metrology (the science of measurement and its application).
In the real world, systems can exhibit non-linear behavior or even chaotic effects that won't be checked in the software (or accounted for) unless you know they can happen (usually from real world experience) and configure it accordingly. In many cases, you'll have to write your own software to handle these problems, or work extensively with the vendor to modify the software (which likely won't happen unless they have a good financial reason to do it).
All software will have bugs, usually in 'corner cases' where the vendor didn't test sufficiently, or in situations where the vendor made assumptions about use that don't match what you are trying to do.
Plus, there are many numerical issues that can cause problems. If you are curious Ronald Mak's book on Numerical Computing is a good introduction to the topic - but keep in mind that this is a very complex topic and people spend their entire careers specializing in it.
Also, just because you have a number, even if it is computed correctly, doesn't mean you can use that number for some particular purpose. Numbers don't always mean what people think they mean, they have to be interpreted and it's easy to go astray. Another good introductory book is How to Lie with Statistics (Huff), but again this barely scratches the surface of a very complex topic.
Good engineers learn how to look for and work around these issues for the particular problems they have to deal with, but that doesn't necessarily mean the techniques will be applicable to the problems you are trying to solve. For example, relatively few of the techniques developed for military sonar are applicable to medical ultrasound: the people specializing in medical ultrasound have had to develop their own techniques that match the problems they need to solve.
After simulation, you still need to do testing in the real world, and that often results in going back to do more simulation, and so on. _Simulation without testing is not reliable except for very simple and well understood problems, and even then it is likely to be very limited in scope or applicability._
What I take away from this is that the decapping plate would have worked as intended if only the Italians had moved the decapping plate outward and/or the armour belt inward enough to leave a one-meter gap. As far as I can tell, most or all of this was above the waterline, so displacement would not be an issue.
Hey Drach! Nice to see you comming to Denmark! While our recent naval history is not overly impressive, go back a few hundred years and that changes right quick. If you ever feel so inclined, give us some input or good stories about the great northern war or the like.
I feel like filling the scheme with concrete would depend veary heavily on the hardness of gravel used. It is in fact eeryly similar to later developed composite schemes, which, granted were meant primarily to counter HEAT-FS at significantly smaller calibers but they still did provide weight efficient protection against kinetic penetrators.
I think it's fascinating how similar the concepts of the decapping belt and Whipple shield are. Thin outer armor then a gap to disrupt the incoming projectile, sometimes people even talk about a "stuffed" Whipple shield with aerogel or similar in the gap.
Due you have a video discussing the Pugliese system and/or comparing it to other torpedo defenses? If not are you planning one for the future?
More tremendous commentary from Dr Achi Nifel
DRACH WHEN UR IN DEN HELDER AND AMSTERDAM I WILL JOIN YOU.
I am a Dutch, I visited both the buffel and hr. ns. SChorpioen. I can tell you something more about those ships! and even givve you some footage ideas
This was very interesting and has some relevance to today's reactive armor.
I hope that anyone trying to model this uses dynamic, not static, material properties. They can be wildly different. Things like impact strength determined by an impact hammer and high strain rate testing like Gleeble testing would be what is needed.
Thank you. Great journalism and entertainment. 🥃
AHH perfect, just in time for my bedtime story
Hello Drach, you can also visit the Marine-Ehrenmal (Marine Honour Monument) in Laboe close to Kiel. The U995 can also be visited there.
What amazes me is how the Italians at the time struggled to produce decent amounts of basic weapons of war like rifles, field artillery , vehicles, tanks and planes etc, but they produced and armed reasonable numbers of very much more resource and manpower intensive, very decent capital ships.
The ships were built pre-war and the large ones not replaced as they were put out of action. Guns, tanks, and fighters need constant production and replacement (and constant upgrades in the case of the tanks and planes). That's where the Italians couldn't keep up - they had decent amounts of gear to start off, but couldn't keep up with their losses and couldn't get improved models into service fast enough.
@@rupertboleyn3885 yes, but also the L3 tankettes were pre-war and they weighted 10,000 times less than Littorios. No much production also for army guns. The truth was that navy had the priority of top quality materials than army and aviation, despite being much less used. The high quality of armour was not present in army's tanks, really shameful to my mind. A lot of men died in italian tanks with brittle armour while the super-battleships were doing nothing else than float in the ports.
When you want to go to Africa but it's across your country, having a navy is pretty much a necessity
TLDW: We aren't entirely sure, but it PROBABLY worked at the desired ranged, but it PROBABLY wasn't exactly as strong as desired.
Only found out today that Nathan Okun had passed. RIP legend
POOR MR OKUN DAMN SHAME!
9:27 - The _late_ Nathan Okun? Oh shit, does this mean NavWeaps is shutting down‽
Was the perpendicular force generated by an angled hit factored into the calculations for distance required to dislodged the cap? I think this should make a substantial difference
Yes, that's why the a calibre-equivilant thickness drops substantially when you account for the angling of the armour and fall of shell as compared to a 90-degree perpendicular impact.
@@Drachinifel ok, I mistook it to just be taking into account the increased distance as a result of the angles
Always Fascinating!!!
The cap also helped align the shell to more of a 90 degree angle when impacting inclined armor or when plunging at high distance. Similar solution was used in tanks in ww2 but the cap on tank shells was strictly soft and was there to align the shell and mitigate the advantage that sloped armor provided.
And strongly contributes one of my favorite things for tank shells of making the longest acronym you can that's still _technically_ feasible. I normally just settle on APCBCHEFSDS. Or Armor Piercing, Capped, Ballistic Capped, High Explosive, Fin Stabilized, Discarding Sabot. You could go with HEAT instead of HE, but that would hardly make _actual_ sense for a shell with an armor piercing cap.
@@chrisc1140And here I was thinking APFSDS was an eyesore, and you just go and come up with 5 more letters to stuff in, you madlad.
@@chrisc1140 You mean as a full-calibre APHE with a cap and a ballistic cap, and its also fin stabilized? That´s quite a stretch. And where would you fit that discarding sabot? I mean, the only thing that typically uses a discarding sabot is the APFSDS, and that´s because its quite literally just a thin rod, and not a huge container with explosives inside and 2 caps sitting on its nose...
@@mnxs tbf his shell while possible to design would be pretty useless.
For one fin stabilized discarding sabot shells are usually steel, tungsten carbide or depleted uranium in a solid rod of metal. They are already quite aerodynamic and self alignment would harm performance so both C and BC are gone.
HE is obviously useless on a DS round since it's a small payload and the payload itself would lower the mass and penetrative performance of the metal dart.
There is a reason APFSDS or HEATFS are the ones used by modern armies, its the current META, even the Brits are dropping their hesh in favor of FS shells.
@@HalIOfFamer And then you enter ukraine and everyone needs HESH and HE, and multi-purpose HEAT is kinda...shit.
But on topic of shell, discarding sabo behind the main APHE? Combined ammo like this is actually possible, and should (technically) work better. Just yeeting a rod of metal is better to deal with armor tho.
00:49 Drach is driving past my Hometown Emden in Germany next year ! :) Edit: The international Maritime Museum in Hamburg has a very nice collection. Particularly of small models on the top floor. In Poland Kolberg has a small military history museum with some Torpedoboot I think.
If you are interested in visiting another u-boat after the one in Bremerhaven, you could check out the U-434 in Hamburg. It's a Soviet cold-war submarine of the Tango class that was made a Museum
I agree with yourconclusion about tve restive effect if foamed concrete falling off considerably compared to solid concrete. And to compare ut to the real world, its why we vibrate concrete to get rid if bubbles, to massivaly increase concretes strength. Concrete that falls apart due to the destructive force of a shell cap hitting it and moving through it, is not what provides the resitive force to remove the cap of a shell.
On the way to Danzig you could pay a visit to the "Marine-Ehrenmal" & U 995 in Laboe, inside the Ehrenmal is a small museum which you will probaly like. Small entry fee, but open all year. More to the east in the Schifffahrtsmuseum Rostock, you find the "Capella" a ferrocement Seeleichter Type Viking build in 1944 iirc.
Would it be possible to do a video on the British 'Plastic Armour '? It wasn't actually Plastic but a mixture of bitumen and Penlee Granite.
Do you meet with people in EU?
Maybe you can see something in Kiel?
In Hamburg is Cap San Diego, and steam powered Stetin. And also huge port.
Always wondered how these would have fared outside the Mediterranean. Of course this was not the theatres of operation which they were designed for. One of the reasons the Allies rejected the proposal. I always marvelled at the rear turret’s placement high above the rear deck. 👍🏻🏴
My understanding is that that placement reduced the blast effect on the lowered stern deck.
@ Thank you. My father served abroad various battleships during W.W.2; Nelson, Rodney, Malaya, U.S.S.South Dakota, and Valiant.
The Queen Anne Towers on the first two ships suffered blast damage initially. I don’t know if that was solved by fitting blast protection shutters.
👍🏻🏴
That way the rear turret could fire above the secondaries, giving it an unparalleled 326° angle of fire.
@@BackwardlookingThe 'solution' for Nelson & Rodney seems to have been to not fire too far abaft the beam, though I'd expect that to go by the wayside in wartime pretty quickly.
The blast firing astern was nevertheless enough that they tended to wreck their own floatplanes.
So, they could have done what was necessary by using a further ~9" of internal space per side, or 18" in total internal beam for the length of the decap and primary belt armour. Is that about it?
In which case the argument comes down to the cost vs benefit, as it always does. What consequences would the loss of those 18" have had? Interesting to consider.
p.s. given they were never hit on the belt, it seems they could've forgone much of the armour and had more horizontal protection 🙃🤣🤣
Awesome vid sir - love the tech specs. It just seems to me, particularly as the complexity of the systems increases, the consistency of the protection would vary much more widely even if it has the potential to stop a 15" shell you know? It might work great on one occasion but the next it might fail catastrophically.
Sooo, a Kentucky Ballistics/Drachinifel collab is in order (or SY Simulations).
if you need to go somewhere between bremerhaven and gdansk, i recommend peenemünde on the baltic island of rügen... they have a soviet diesel sub as museum ship and also a small missile ship...
and tho it might not be the topic of your channel, the museum for rocket developement there is a must go to!
usedom i meant... my bad
Adding numbers and some sketches to the slideshow as notes would have been welcome, especially those last 10 minutes.
Hi Drach, did any navies experiment with shaped charge HEAT rounds, or was that just an army thing at the time?
Postwar the soviet P-15 Termit (NATO codename Styx) had a HEAT warhead. Probably an attempt to allow it to penetrate BB armour, despite its subsonic speed.
The warhead massed 1000 lb and given the technology of the time and the missile's 750mm diameter could probably penetrate about 750mm of steel.
Near Stralsund there is an old Marine Museum on the island Dänholm.
Have you ever done an episode on Churchill's crazy "ice aircraft carrier" or the wooden cargo ship boondoggle of WW1 or the concrete ships of WWII?
Concrete ships = Mulberry
@@gbcb8853 No. Cargo ships. Before Henry Kaiser revolutionized ship building there was a plan to make concrete hulls.
There is a video on the proposed HMS Habbukuk (spelling?), the ice (well, technically Pyecrete - ice reinforced with sawdust) giant aircraft carrier. Unless it was a Drydock segment.
This bring back a memory, I would say dry dock but it is a few years back@@alexandermonro6768
@@alexandermonro6768 - Guide 113, released Mar 16, 2019
ruclips.net/video/2-8ppT7TYrg/видео.html
Note, the section, were it was discussed in a meeting with Roosevelt & Churchill present, were Mountbatten shot a Pykrete sample, in their presence, and the ricocheting bullet punched a hole in Admiral King's pants. The old days were truly golden !
Though, he has discussed it many times since, including some Drydock questions.
Maths with Drach. Come back next week and learn about the differential calculus involved in the making of a cappuccino. Don't forget to bring your slide rule!
Talking of decapping armour...I've read of so called "plastic armour" that was developed after Dunkirk, as operational research had discovered asphalt decks on certain ships had offered unexpected levels of protection against armour piercing machine gun rounds. Put simply a matrix of an elastic matrix is used to support extremely hard gravel. Royal Navy wasn't happy with idea of it being called armour/ armouring merchant ship, but it did see some limited use, due to how easy it could be added to ships. I'm guessing that in effect it was annother way of decaping rounds. It does appear idea got developed into certain modern tank armours. Was it ever used on capital ships?
That sounds suspiciously like composote armour as evwntually developed in tanks, which usually involves some extremely high harness material such as tungsten carbide beads in the case of T64, fiberglass in the case of T72, or highly angled martensite steel plates in Dorsetshire composite, suspended in aome sort of amorphous polymer, resin or rubber.
@egoalter1276 yeah modern composite tank armour is supposed to have it's origins with the 1940s invention of "plastic"(meaning "easily castable") armour used on merchant ships. As I said I'm surprised it didn't see use, in between times.
So may I ask which ships were actually hit by heavy shells directly on the belt armour without significant damage?
I don't know of WWII battleships actually hit on the belt by other battleships. In all the engagements by ships of similar size, the main point of impact seems to have been turrets.
@@neutronalchemist3241 Take a look at the paper Kirishima Damage Analysis by Robert Lundgren. Or Drach's video on Bismark and the Cameron expedition. In both cases it is known for certain that there were hits on the belt that penetrated.
I don't know offhand how much damage Bismark took from the hits that penetrated the belt. In the case of Kirishima, we know from the report of her damage control officer - who survived the action - that there was some serious damage.
Unless divers have taken a look, it's hard to know whether there were hits to a ship's belt that didn't penetrate the belt. Even if divers have taken a look, it may be hard to tell in the event multiple shell sizes were being fired. Ships roll and that affects whether or not shells detonate.
There could very well have been hits by Bismark on Hood that were stopped by the belt and simply never reported - there were very few survivors when Hood blew up, mostly men blown into the sea when the ship exploded and young enough to survive (despite being exposed to the frigid water) long enough to be picked up.
In the case of Bismark, there were likely also many hits on the belt that didn't penetrate. It is clear that both the 14 and 16 inch shells being fired at Bismark could penetrate the belt, but it may have required the ship be at an appropriate angle during a roll.
One side of Bismark is buried in the sea floor, so we'll probably never know about any hits to that side.
It is believed that a hit from Duke of York penetrated the belt of Scharnhorst, destroying a boiler room. Here again it's fairly likely there were hits that didn't penetrate - in a Force 8 gale the ship would have been rolling quite a bit, changing the angling of the armor from hit to hit - but I don't know one way or the other.
Love the idea of decapping plates, but more for repair than wieght savings. Easier to repair a outer "thin" plate than a thick inner belt.
The huge advance in tank size guns & armor requires more research which means more money. Winners of ww2 had better things to do in 1946 than play with ship armor. Existing ships were made of spaced armor so heat and hesh don't work as they do on tanks which have 1 compartment.
Hesh is interesting for better fuse at long range but HE already existed and 30k meter shots on radar control was proven too late for caring. No one running around trying to make that when missiles offered range.
Just to throw another spanner into the works - assuming aerated concrete, what would the effect of reinforcing bar (re-bar) be? Negligible on the bar reducing the KE of the projectile directly, but it could potentially provide a mechanism for energy dispersion that holds the concrete more in place as the shell passes through? Just a stray thought
You also have to consider what was the maximum plate thickness which the italian industry could reliably produce. If the main belt was already at maximum thickness then the decapping + concrete route may have been the best answer within the capabilities of italian industry.
You missed the bit about that and the 15inch faceplates on the turrets.
Drach covered this - he mentioned early on that the the turret front plate of the Littorios was 15 inches, so they could make plate that thick.
@@CharlesStearman
And in the first three minutes, no less.
I think the keyword here is reliability produce, I don’t disagree with some of the others that Italian industry could make 15 inch plate. But a few plates for a turret face is a far cry away from an entire armor belt.
So perhaps they could make it just not in the requisite numbers.
@@thedyingtitan1247 what are you talking about, they are not few plates they were 28 plates in just 3 years, this level of production is matche only by 3 other nations, Italy could had built them with a full 350MM plate or 381MM plate, as Italy has been at the forefront of metallurgic since late 1800s, its like one of the most famous aspects of italian naval industry.
Maybe not exactly within the timescales of the channel but there are a Juliett sub and a missile attack boat/corvette at Peenemunde which is between Wilhelmshafen & Gdansk. Plus there is of course the museum where the V2 was developed.
Otherwise there is Gorch Fock near that in Stralsund
Very interesting analysis! I wonder... you now calculated the worst-case situation where a shell is coming perpendicular. What about when it comes at for example 20 degrees to perpendicular?
I can imagine that equal protection to regular armor at perpendicular impact is considered sufficient when at the same time you also get significant better protection at different angles. After all, in combat you'll probably are either closing the distance to your opponent when engaging a weaker opponent or increasing distance when disengaging. Even when keeping distance, you still might be laterally displaced and not having the gun bear perpendicular to the ship.
The instances at which incoming fire is near perpendicular to the ship is probably quite rare compared to different angles.
Great video
take a detour with the ferry to karlskrona, i'll show you around the naval museum (active duty navy)
Fascinating!
If the Iowa STS plate was not a decapping plate, what was its function?
Maintaining the hull lines and volume since the armour belt was sloped inwards.
Very interesting, thanks for posting. I'm wondering if the Italians were making a deliberate choice between armor thickness and speed. Such a choice might factor into the armor scheme chosen.
happy to see you are going to denmark i cant remember where but i reckomend to visit the battle of justland museum they have a really nice model of hms duke of york ive belive ohh and they have the gun of the u20 that sank lusitania and having seen frigatten jyland many many many times she is a beauti of a ship
My question would be how would they repair that armor at sea? Would they carry additional foam concrete or forms to make it on board? Or hope that another shell doesn't hit the same spot?
You don't repair heavy armour at sea. You plug the hole to keep the water out, and decide whether the damage done leaves you mission-capable or not. If not, you try to get home. This is what happened to Bismarck, though she wasn't holed through her armour, but rather in an unarmoured part of her bow. The hit didn't leave her in any danger of sinking, but slowed her and caused her the loss of fuel and to leak fuel.
No battleship, or other class of armored ships, could repair or replace its armored plates at sea.
Considering that practically no battleship had been hit by another batleship on the belt in all WWII, what were the chances for it to happen twice in the same spot?
there were MUCH more chances for two torpedoes to hit the same spot, but battleships had no mean to repair their torpedo defenses at sea as well.
How would you accomplish a perpendicular hit on an inclined armorplate?
Ships roll in the ocean due to wave forces, and since the armor moves with the ship, the angle of incline changes.
A lot of time and effort has to be spent on dealing with the consequences of roll in ship design. Warships even carry an instrument called an 'inclinometer' to measure the amount of roll, which you can see on some of the warship tour videos.
Plus, you never know what shells will do in the real world. They might skip off the water or the deck/structure of another ship, then hit a second target, in which case the angle of impact could be very different from theoretical predictions or predictions based on overly simple measurement. Skip bombing was a deliberate technique that was quite effective in WW2.
In Tanks composite armor has surpassed solid plates, so at least we know the Italians where on the right path, but of course who knows whether their implementation was good.
Thanks. That was interesting.
.
How would filling the gap with water have compared to concrete?
Regia Marina always put the looks slider to 100
It seems to me that it had not been taken into account the main effect that hitting spaced armors at an angle has on a projectile, that's to make it tumble before hitting the main plate. That BOTH should help with decapping AND reduce the needed thickness of the main plate beyond the simply geometrical figure.
You'd think the foam would increase decapping by allowing the shell to tumble more than normal concrete. A simple UK friendly test would be using a Ramset concrete nailer. Would need equivalent samples of hardness and density.
Modern NERA armour does in fact use foams as interlayers.
The Littorio's were some of the most good-looking ships ever made, looks are not always what counts though.
Was supposed to go to sleep, but I can't miss a Drach video especially if he is talking about the Littorio's
Regarding your travel; there must be something navy related in Kiel, besides the navy memorial...
Maybe we can ask SYsimulation Chanel to do the testing simulation.
Don't know if it's publicly available but Sweden did ALOT of tests with concrete for their coastal forts.
So what happens to the ballistic cap when it hits the decapping plate? Where does the cap go, that it no longer stands between the armour and the main body of the shell?
That is irrelevant as long as it was dislodged from the main body. The cap on itself has little penetrating power since the main body of the shell provides the energy. And the main body itself (though higly energetic) is too soft to penetrate the armour.
@@vitkriklan2633 Thank you for the answer. But perhaps I worded my question poorly. So bare with me.
The shell hits the decapping plate, and the cap gets dislodged. But the main body of the shell still pushes forward, and the now dislodged cap is still physically present in between the armour and the shell (I assume it did not evaporate), so where does it go? Where the physical remains of the cap go after the impact, that it no longer is in the way of the rest of the shell?
Now if a large swell was running at the time of battle, remembering that the navy of whichever country owns a fighting ship has no control of the weather, which of course includes the motion of the waves that affect the rolling of a ship particularly if the wave motion is coming from port to starboard, or in fact the other way round, then the said rolling of the ship ould nullify the angle of the armour plating, meaning that if a shell were fired from 16,000 M or about 17,000 yards and struck the side of a ship whilst the armour plating was perpendicular, meaning it was upright, then all the calculations about shell piercing would be null and void.
wonder if chobham armour would be possible in ww2? and would it help?
simple answer: the armor belt was never hit by a shell, therefore at least one of their protection schemes worked, whether or not that was the armor.
in first half of 2025 in Gdynia should be available ORP Sokół. Maybe you like chek it too
Actually most of the questioning I’ve seen has been much more about the Littorio Class torpedo protection (or Pugliese) system
Analyzing the damages it received, it worked quite well, with good containment and short repairing times. The Soviets tested it in real scale against the traditional spaced system, and chose the Pugliese for the Sovetsky Soyuz class battelships. The results of their tests are available online.
The Navweaps critique of a "dam mistakenly built bowing downstream" doesn't make any sense. If that's true, the traditional systems are dams with an outward 90° angle, that's even worse.
Conte di Cavour and Caio Duilio at Taranto had not been hit in the Pugliese System. The torpedoes, ricocheting from the surface to the bottom of the harbor, exploded under the keel, in the worst location possible (is to purposedly achieve similar hits that magnetic fuzes had been later introduced).
It sounds to me like someone got confused during the design process and failed to account for the concrete adding weight when drawing up the construction plans then realising their mistake switched to foamed concrete after construction had started to " fix" their mistake. Either that or the foamed concrete performed well during testing with the smaller shell's and they failed to realise that using a testing regime designed for solid plate couldn't give reliable results for a composite armour. Not an obvious oversight at the time because it's very easy to fall into complacency when you have a well established reliable procedure for something and just don't consider that adding new variables might make the procedure fail.
It seems to me that the clip had not taken into account the main effect that hitting spaced armors at an angle has on a projectile, that's to make it tumble before hitting the main plate. That BOTH should help with decapping AND reduce the needed thickness of the main plate beyond the simply geometrical figure.
4m24s Couldn't help but laugh at the joke in "The Dictator" ( Sacha Baron Cohen) about the pointy bit of a missile needing to be scary,.