Why was German Sloped Armor so late?

In this video we look at German sloped armor, how it is different to Allied sloped armor and potential reasons why it was introduced so late. For this we look at how the Germans welded their sloped armor differently, although this might be just a coincidence.
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Raths, Ralf: Geschichte(n) aus Stahl, Folge 15 (2/3): Der vergessene Blitzkrieger - der Königstiger (Teil 2/3). Das Panzermuseum. • Geschichte(n) aus Stah...
Köhler, Frank: Panther - Meilenstein der Panzertechnik: Bemerkungen über ein wegweisendes Waffensystem, Schneider Armour Research: Uelzen, Germany, 2014.
Rau, Walter: Panzerungen mit besonderer Berücksichtigung gepanzerter Fahrzeuge zu Lande, Bundesamt für Wehrtechnik und Beschaffung: Koblenz, Germany, 1973.
Pulham, Francis; Kerr, Williams: T-34 SHOCK: The Soviet Legend in Pictures, Fonthill Media: Stroud, UK, 2021.
Jentz, Thomas L.: Der Panther: Entwicklung, Ausführungen, Abarten, seltene Varianten, charakteristische Merkmale, Kampfwert, Podzun-Pallas: Wölfersheim, Germany, 1997.
00:00 Intro
German & French Sloped Armor before 1941
00:57 Why no sloped Armor on Panzer III, IV & Tiger?
01:32 Why non-sloped Armor was preferred by the Germans?
01:59 Tiger Promo
02:49 Structural Integrity
04:36 see the difference
05:39 T-34 Interlocking
07:46 Jagdpanzer 38 “Hetzer”
08:08 Why not earlier interlocking Armor?
08:47 Warning! Different Views!
09:01 Effectiveness?
10:24 Why no more Interlocking after 1945?
11:17 First Summary
12:29 Different Viewpoint / Second Summary
15:00 More Research needed
#slopedarmor #tanks #armor #germantanks #germanyarmy #germanarmyww2

[@MilitaryHistoryVisualized]

Get our books here: militaryhistorygroup.com

[@darthcalanil5333]

the link takes to a Cloudflare error screen

[@joe6167]

It might be worth your time to look through Battleship New Jersey's channel, as they have made a number of videos on the implementation of welding into the construction of the ship, and the transition from riveting to welding. As welding was still an experimental process at that time they might have gone overboard with it, and all throughout the ship you can see how all the welds between the armour plates use a unique "scalloped" design, I guess to get as much surface area as possible, as opposed to a welding in a straight line. Perhaps the Germans were trying increase the surface area of the welds with the interlocking plates?

[@SlinkyTWF]

Is it possible that the interlocking of the plates could have been done as an aid to properly fitting and aligning the armor to make the assembly and welding easier and more consistent? I don't what the difference would have been in the factories regarding how the workers fitted the plates in position prior to welding.

[@TheRezro]

Short answer. It was unnecessary. Germans achieve this effect through tactic and proper angling against the target. While having profit of larger internal space. T-34 is heavily overrated and its angled armour was more due to poor quality of Soviet tank crews. Germans start using this effect more with they late tanks (if you ignore that King Tiger have horrible shot trap), where need of space was not so crucial anymore.

[@pierQRzt180]

uh the library grew a lot, before there were good works but not of my interest, now it is different!

[@bami2]

Germany forgot to buy the WW2 season pass and the sloped armor DLC was only available to non-premium players in '44

[@piellamp]

Gotta hate pay to win wars

[@RT-mm8rq]

Sloped armor or not a small fast and stealthly premium ( pay to win) light tank or TD comes on the battlefield that some how bounces hits from large calibers guns, is armed with a rapid fire small caliber cannon OR a large rocket that always seems to kill your crew, track you or set your tank on fire.

[@T.efpunkt]

Understandable, these "service-based" monetarization models suck.

[@user-tc9sk4ei9y]

They paid for armored cars DLC though

[@user-tc9sk4ei9y]

​​@@T.efpunkt"War is a pay-to-win game" (c) Giovanni Trivulzio, famous wargame designer of late Middle Ages

[@brennus57]

Thank you for this perspective. I've been puzzled that so many people fixate on the idea that the concept of sloped armor began with the T-34. You can see sloped armor on the ironclads CSN Virginia, Arkansas and Albemarle. Also thousands of examples in medieval tournament armor. This principle had been understood and applied for centuries.

[@karlheinzvonkroemann2217]

Can't argue with that one!

[@user-tc9sk4ei9y]

The concept of a fort made of wagons is known at least since the first Indo-European nomads begun spreading throughout the Eurasia, but people fixate on the idea of wagenburg being invented by the czech hussites. Why? Because they were the first ones to make it into a system and employ such tactics with significant results against an opponent deemed to be superior in all aspects previously. The same goes to T-34. Germans didn't have all the bright ideas in the world, whatever the wehraboos are imagening to themselves while jerking off on panzers

[@pex_the_unalivedrunk6785]

Leonardo DaVinci tank concept also had sloped armor

[@user-tc9sk4ei9y]

@@pex_the_unalivedrunk6785 gErMaN tAnKs hAvE sLopEd aRmoR aT tHe nOsE tOo!!1

[@2ndSSdasReich]

Vodkaboos will say time began with the creation of the t-34

[@oskar6661]

When people think Germany didn't "understand" sloped armour...I always wonder, 'Where do you think their engineers got their degrees?'. Sloped surfaces are basic physics/geometry/material sciences '101' level stuff.

[@mcourage345]

Somehow German's completely missed the medieval armor period apparently lol

[@nightshade4186]

Yes it's Pythagoras law

Also, after WW1 Germany had many restriction on what they can and cannot do militarily. Soviet Russia helped educate German military in their war academies. And USSR and Germany where allies it the beggining of the war from 1939 to 1941. So Germans knew very vell what Russians where doing.

[@KuK137]

And yet somehow these geniuses never applied it anywhere in tank design producing complete trash design one after another until Russians made them laughing stock with T-34. Go figure...

[@KuK137]

@ Bullshit, if they were allies, nazis wouldn't send arms and men to countries attacking the soviets and soviets would help them with fighting somewhere. Pull the other one, yes I know russophobic revisionists produce endless nonsense today but there was no alliance, mild neutrality at best. And funnily enough soviet designs went completely ignored and laughed by nazis (because these dumb slavs can't produce anything better than us, right?) until they saw T-34 in action and collectively browned their pants...

[@fallschirmjager0000]

Great video. Alot of the reason the Germans stayed with box structure armour, besides simplicity of construction was due to crew ergonomics and turret ring size. Sloping it will steal space inside the vehicle, reducing ammunition, fuel and crew space. The Tiger for instance was required to have an 88mm gun, sloping the armour would have reduced the size of the top deck, thus reducing the turret ring size and therefore the gun size. The tanks still had to follow the rail gauge so making them wider was not possible. The quality of the armour was also good at that stage of the war and with trained crews that were able to position their machines correctly when engaging.

[@jarink1]

I have also read that turret ring size was an important factor in not sloping armor. This was especially true for Tiger I, with the superstructure overhanging the tracks giving even more room for the turret. Sherman and some other designs also incorporate a large ring with overhanging vertical sides. The T-34 was unique (at least early on) by using the side overhang in combination with sloping.

[@neurofiedyamato8763]

Not all volume is useful. When the driver is sitting upright, the space infront of his torso is unused space. You can slope that just fine. Also frontal slope even very extreme angles rarely affect turret ring size due to ocerall vehicle length. Its sloped side armor that narrows the roof plate, and thus the turret ring. There really isn't any single rule for sloped or flat armor. Its all circumstantial and depends how it is implemented.

[@kirotheavenger60]

Sloping side armour is not very common, precisely because of the high cost in internal space/turret ring. Sloping the front, however, has very little spacial penalty, as the driver's body is kinda sloped anyway (you can just take the hypotenuse of the stepped front). The cost for mounting it on the front is it reduces the practicality of MGs and driver's vision blocks. This is why you often see "bulges" around these areas on sloped fronts. Until tanks dropped the bow MG and switched the periscopes for vision

[@cheyannei5983]

​​​@@jarink1Tiger I was more the result of "forced errors". They had asked for 80mm of armor, an insane quantity of ammo, high fuel capacity, a reliable transmission, powerful high torque engine... There is no way to fit all of that within the weight requirement without the most volumetrically efficient shape; a box. That's not to say it couldn't have been better. Did the floor and roof really need to be so thick? The plate under the sponsor? The rear? All of those places will shed many tons and free up plenty of weight for blowing it on the front for sloping's volumetric inefficiency. The Soviets did exactly that with T-34-85M. (and never approved it for serial production...)

[@Cornel1001]

NIce try !

[@timob3490]

Also welding had just been adopted for major industrial production. So welding processes were there but structural design had not really been adapted to the process. The interlocking plates are a really good example. They only chose to do so because the structural integrity would be better this way because they did not manufacture full weld penetration on the armour plates. This was a compromise on integrity and welding. The plates support themselves somewhat better by interlocking. But it makes welding even harder. You can tell by the poor weld surface and layers on these joints.

[@T.efpunkt]

True. Interlocking increases the length and complexity of the weldseem, which was arguably the weakest part of armor back then.

[@carstenlichy-bittendorf3902]

Right, but the interlock keeps the plates better in position. This especially when welding plates in complex angles by less professional staff. So the interlock might simply have been a need for manufacturing. Just a thought - not a fact

[@Tuning3434]

@timob3490 True, but most of the welding was used in structural steel, not armour steel. I don't think this is the reason why it is used in armoured components, but in sheetmetal products those battlements are used (usually cause it is a 'free' functionality in a laser cutting process) to both position the individual plates, reduce the amount of weld (not the case in the armour) and to limit deformation due shrinkage of the welded area, actually, the weld shrinkage (in a proper quality weld that doesn't crack!) pulls plates in a stronger connection. I wonder if it was an attempt to limit welding jigs, by having the plates interlock closer together themselves? It feels a bit ungerman lack of Handwerkskunst, but it doesn't really show up til Germany really wants to ramp up production.

[@MarcosElMalo2]

Some of the welds look terrible with inadequate penetration. It looks not so much like welds but like they were stitching the plates together with small diameter filler. The weld on the M-10 looks sloppy but adequate. We can’t tell from a video of painted surfaces, but I imagine that the plates had been bonded into a single plate. I find it hard to believe that the Germans didn’t understand the welding process, so I wonder in the “joinery” was to compensate for a shortage of skilled workers on certain production lines. It would have been funny if the used dovetail joints. 😅 Supposedly stronger than finger joints.

[@gore0ru]

@@carstenlichy-bittendorf3902 - A novice welder will not weld such complex joints well.

[@silmarian]

“I was [certain] at one point and then I started to ask too many questions.” I think we’ve all been there. Sometimes the more information one has the less clear the answer becomes. I appreciate you being upfront about that.

[@Punisher9419]

All the German tanks still has slopped armour, it just wasn't slopped everywhere because of space problems. Even the front plate of the Tiger was slopped backwards a little 10 degrees I think.

[@_ArsNova]

Yes, exactly this. The Panzer III, IV, Tiger, all had sloped armor, just at very shallow angles. Sloping armor is always tradeoff between extra effective thickness, and decreasing interior volume and crew ergonomics. Soviet tanks are infamous for their atrocious crew ergonomics and coffin-like interiors for a reason.

[@TallDude73]

@@_ArsNova Agreed, I thought sloped vs. shallow-sloped armor was just a design and engineering choice. Sloped armor means more metal (the hypothenuse of the triangle) which weighs more (unless made thinner, in which case you lose the benefits somewhat) and covers a larger volume inside the tank. Not all of that volume is useful, and will be used mainly for the driver's and bow gunner's legs.

[@mrdojob]

The problem with sloped armour is that it doesn't actually help as much as people think. Sure you can tilt an armored plate 45 degrees, but in doing so you have to make the plate itself bigger to cover the same space as an unsloped plate. Sloping also creates a lot of space inefficiencies. You can cram more into an After 8 mint box than a Toblerone box.

[@aleksazunjic9672]

@@TallDude73 Slopped armor allows ricochets and this is its major advantage over straight armor of similar thickness. Disadvantage is that you have less space inside, i.e. you have cramped tanks (well known fault of Soviet tank design) .

[@_ArsNova]

@@mrdojob People also forget that sloped armor is only useful as long as it's sloped. It is rendered worthless if you happen to be caught in a position where that angle is nullified, such as while the tank itself is on an angled slope, or is being fired on from higher ground.

[@RJ-vb7gh]

I'm not sure this makes any sense to me, but as a young man I knew a "tank escort" for the German Army (the guy who walks along side tanks into combat), He served from the beginning of the war to the fall of Paris. Mainly he escorted tiger tanks on the Russian front until losing a kidney and being assigned to guard a tiger during the fall of Paris, where the tank overheated and he got captured still escorting it. So here's the weird part... he told me that the way the Tiger was designed to deflect shells straight upwards. And he claims that's exactly what they did in his actual experience on the Russian Front. He mentioned that Tiger crews preferred to assault or defend from the high ground. and he also added that most Tiger gunners could hit a moving jeep at 1000 meters. While I have to agree that it's unlikely that incoming shells would ever come at a tank straight on I don't quite understand why incoming shells would always ricochet straight upwards. Lastly, at least through quite of a the war, German tankers weren't too concerned with Russian tanks or most other Russian munitions that they were encountering. For the most part they felt that they could outrange the Russians and survive incoming hits. I wish I remembered more of that conversation, but that was nearly 50 years ago.... Perhaps for WW 2 buffs in general, I'll add a couple of fun trivia that he told me: On the offensive towards Moscow the tank guards were usually tasked with capturing meals. For the most part this involved capturing Russian soldiers and confiscating their food. They might capture up to 60 Russians in a morning forage and he said, the Russians didn't necessarily have bullets, but they always had good food. He went on to tell me that things went terribly wrong when the quality of the Russian Food declined and the Russians suddenly became flush with resources and ammo. In his mind the Russians had somehow built a great factory that produced everything they needed and cost Germany the war. He didn't speak Russian or English, but he memorized the name of the factory and he wrote it on the barn wall in pencil.... it read...."Made in USA" which he pronounced as one word in German and I didn't get it until he wrote it. I of course translated the word for him and we both walked away from the conversation having learned something. It's been 50 years and I thought I might share this little story before it's lost to history.

[@keithbosch37]

"Madeinusa", thanks for sharing this.

[@stage6fan475]

Thanks a lot for sharing this.

[@2Pzp]

Great history! 50 years ago? How did you meet him?

[@RJ-vb7gh]

@@2Pzp I spent a summer living on his farm in Germany as a kid. He was my mom's first husband's step brother. He didn't have a son, so he spent time with me teaching me about farming and every once in the while sharing his WW 2 experiences with me. He was a quiet and contemplative man who liked to work with his hands and with animals. He made it all the way to Moscow and ended his military career in Paris. Along the way he earned an Iron Cross with decorations and I suppose is now one of the many that were heroes for a time and have since been lost to history.

[@ZaHandle]

The magic factory known as 1940s USA

[@grizwoldphantasia5005]

Keep on asking questions, they are interesting. Answers are better, but you can't have answers without questions first.

[@kilianortmann9979]

Sloped armor is not a magic bullet (pun intended), a sloped plate will have more effective thickness, but it needs to be longer to cover the same frontal height. Those two effects will exactly offset, the main advantage of sloped armor comes from normalization effects, simpler production of thinner plates and better surface to volume ratio, when designed correctly. For modern APDSFS projectiles with a large degree of positive normalization, sloped homogeneous armor can be worse than a flat plate. Especially in a WW2 context there are definite advantages, but also tradeoffs.

[@quantum340]

Yes! Thank you! It always drove me nuts to hear that 'sloped armor increases effective thickness for the armor without increasing its actual thickness, so you save weight' when simple geometry shows the increase in length of the armor plate would cancel out any supposed weight loss.

[@thrall1342]

This, 100% I have been writing this for some time as well ... angling a plate doesn't save weight by itself. The weight saving come from decreased surface area you need to cover and less internal volume.

[@quantum340]

But can you explain these 'normalization effects'? What are these and how does it affect flat and sloped armor?

[@kilianortmann9979]

@@quantum340 If a projectile hit's a plate of armor at an angle, it gets deflected. For a normal upwards sloped plate, most basic bullets get deflected upwards, like a ball. They don't penetrate the line of sight thickness, they need to penetrate a longer way, leading to increased effectiveness of sloped armor, this is de-normalization. Specialized armor piercing caps will "bite" into the armor, deform and turn the rest of the projectile downwards.The projectile will now only need to penetrate a shorter distance, closer to the plates actual thickness. This is normalization (the projectile turns towards the normal [perpendicular] to the plate) and this makes sloped armor less effective. Modern armor piercing projectiles and especially APFSDS have positive normalization. Example of WW2 era de-normalization kzbin.info/www/bejne/m6vJYZWOYpqFZqM Example of APFSDS normalization kzbin.info/www/bejne/ZqWQh5xqqtOHgrM

[@piotrmalewski8178]

That's why T-34 was supposed to made of high hardness steel to make advantage of the armour angle to deflect shells, but it had side effect of internal cracks hurthing the crew on hit, and Soviets had trouble maintaining any production standard in the first place.

[@pugnate666]

From an engineering view I want to mention 3 different effects of interlocking plates: 1. Your welding surface is bigger. Welds are a weak point, therefore you want to spread the load over a larger surface. 2. Shear forces between two plates are put onto the much stronger "teeth". (E.g. side view of a shell hitting the front of a panther. The frontal plate is forced inward and up by the impact. The interlocking on the sides of the plate works directly against these forces. 3. Welds handle load in different directions differently well. So interlocks change the direction at which forces act on the weld. (E.g. Frontal view of a shell hitting a panthers' upper plate: Again the plate is forced up and into the tank. A flat weld between upper and lower plate will just get pulled apart and open like a zipper. At interlocks, the weld experiences shear forces, which it can handle better and prevent the whole weld opening up as one.) Thanks for the video about this interesting topic!

[@pRahvi0]

Considering welding was quite a new technology and yet to mature, the welds of the time were or at least could often be weaker than after the war. I'd imagine once the welding techniques developed and welds became more reliable and better understood, the need for complicated joints was no longer there (thus interlocking disappeared from use), but it might well have been at the time they were used.

[@mordentus]

Large metal plates warp during welding. To prevent this, one needs to either build massive supporting framework or interlock the plates

[@russwoodward8251]

In manufacturing, interlocking plate would make the jig necessary for hull assembly, simpler, as the locking tabs would insure alignment in two directions. Since these plates were heavy heavy heavy, simplifying the jig would be a goal of any factory engineer for sure. The Soviets may have tried it for the same reason. To simplify alignment for assembly. Thanks Bernhard!

[@danielstickney2400]

This type of keyed joint is commonly referred to as a "box joint" in English. You may wish to contact the Australian Armor Museum for their opinions about keyed armor joints, their restoration shop has actually welded blown-up German armored vehicles back together. They observed minimal and inconsistent use of armor grade stainless steel welding rods in the late production Stug 3 they are currently restoring, no doubt due to late war shortages,.

[@MarcosElMalo2]

I am very curious about the weld penetration the Germans were achieving (or failing to achieve). And I further wonder if this was caused by material shortages (as you suggest), skilled worker shortages, or welding technology lagging plate thickness. If box joints were supposed to improve structural integrity, why not go further and use dovetails? 😂

[@ianslaby5703]

@@MarcosElMalo2 the box joint is already inefficient compared to a straight line weld. Think about the fact that this would further increase the length of the weld and make the fitting of the armor plate even more difficult than a box joint no doubt does. Man hours are expensive, this might have been a compromise solution.

[@_ArsNova]

My eyes almost roll a full 360 degrees any time I see someone talk about sloped armor as if it began with the T-34. The Germans had been sloping tank armor since WWI with the A7V. The literal first "tank" concept in Leonardo Da Vinci's drawings from 1487 had sloped armor!

[@Blox117]

so what you are saying is that leonardo da vinci was russian?

[@josephahner3031]

Da Vinci's tank didn't have sloped armor for the purpose of increasing protection, but because of how the armor would be constructed, bound at the top.

[@_ArsNova]

@@josephahner3031 Perhaps, but even back then people understood that cannonballs and other projectiles were more easily deflected by angled surfaces.

[@oskar6661]

Fun fact, Leonardo Da Vinci's tank could withstand a 76.2mm ZiS-3 AT gun at distances of between 600+ meters.

[@gore0ru]

@@Blox117 - Or German LOL

[@pavelslama5543]

Vehicle designers of that time had only a vague knowledge of the effects of shell denormalization, and how to instigate or mitigate it. Their thinking of the efficiency of armor boiled down to mostly sine of the angle from horizontal. What it means is that they said "80mm at 40 degrees from horizontal? That´s just about 125mm. That´s not good enough." Meanwhile the reality is that almost no shell was stable enough in order to "bite" into that angle without major deviation upwards. Modern simulations suggest that Panther II with its 100mm thick front armor would be almost impenetrable even to the mighty Soviet 122mm gun.

[@nattygsbord]

125mm is good enough. It is very good. Tiger I was considered almost impossible to knock out and it "only" had 100mm front armor. So personally would I consider 70mm armor with say a 50 degrees slope (or more) to be good enough for a medium tank. Having thicker armor than that would only be wasteful in my opinion and bring extra weigth, slow down the tank, make the tank too heavy to the front, having too much armor at the front so weight have to be saved by cutting down side armor and making the tank weaker and vulnerable to hits from the sides, rear and top. So I think your suggestion is a bad idea. And then it also depends on the type of tank. Hetzer would I consider to be extremely well protected. Its small and easy to hide. And the enemy cannot shot at you if he does not know that you are there. And when he discovers you, then he will have a diffucult time hitting a small target like the Hetzer. And Hetzer in a hull down position its even harder to see and to hit. And if you manage to hit it, then will you probably only hit it where the armor is the strongest - the frontal top of the hull. And there will the thick armor with a sharp sloping give pretty good protection, even against pretty large caliber guns at longer ranges. So its a pretty cost-effective use of armor the Germans had with this little vehicle.

[@sergeyboychuck8872]

reality harsh, IS-2/3 had zero problems with their 122 mm against Tiger's.

[@sergeyboychuck8872]

@@nattygsbord you just described T-34/85. my congratulations!😁

[@nattygsbord]

@@sergeyboychuck8872 T-34 and M4 Sherman did have sloped armor and somewhat okayish thickness. So I think they were better designs than the German tanks that either had crappy armor or was too frontally heavy. I guess low quality steel in the russian tanks made their frontal armor not so fully effective as their american counterpart. And bad tank crews and poor ergonomics and other shortcomings could probably explain much of the high soviet tank losses. But the general idea was sound. It had frontal armor of the right thickness. And it had a gun of almost the same calibre as a Tiger I and inside a medium tank.

[@nattygsbord]

@@sergeyboychuck8872 But you are comparing apples with oranges I think. Tiger I was an old design. It was very good at its job facing tanks made before its introduction in august 1942. But it was never really meant to be invincible against tanks made after that. And the Soviets also deliberatly armed their tanks with the only guns they had that had been proven effective against the Tiger - such as the 85mm Anti-aircraft gun they put in the turret of T-34. And the 122mm gun they gave IS2. And the 152mm gun on SU-152 and ISU-152. No tank could survive a hit from those guns. Just like no tank today can survive a direct hit from a 155mm or 152mm artillery piece. But it would be stupid to say that armor protection does work because it cannot survive direct hits from high calibre guns.

[@billyponsonby]

Very interesting. Not all research arrives at a neat, interlocking conclusion.

[@karoltakisobie6638]

From welder's perspective: straight welds are faster and worker doesn't need a lot of experience to make a good weld. Interlocking plates present a challenge because on one hand welder can do his job in such a way that will prevent material/ weld stress ( comparing to straight weld). On other hand interlocking joints will take much more time, effort and weld quality will be often questionable. Look at pictures of knocked out tanks. Very often it's the welds that let go,not armored plates. Want to make welder's life hard? Design welds like those of Churchill tank ( as observed on example in Borden Base Ontario, Canada). What a nightmare.

[@MarcosElMalo2]

And if it’s the welds blowing out, that means their welders aren’t getting full penetration.

[@shiftymcgee4183]

Love the progression of this video as more information comes to light👍

[@ThePerfectRed]

One important aspect of straight box armour is that you can use the inside surfaces much more efficiently to mount equipment, and it generally gives more room to the inside.

[@MrEolicus]

Thank you for being honest. When one speaks plainly about what one knows and one knows not, a new plethora of information is conveyed. It also messes with your intellects in a good way... certainty is a transient state. That fact is often forgotten. Great channel! Cheers.

[@vladimpaler3498]

Another thing to consider with the interlocking plates is that you get more weld length and it is split across both plates. A simple butt joint leaves the plates subject to flexing along the weld length, while interlocking provides more rigidity. Might help keep welds from failing when a shell hits and flexes it.

[@unknown0soldier]

This video left me with more questions than answers. And I think that's cool, so thank you!

[@MilitaryHistoryVisualized]

Thanks! Same here :)

[@causewaykayak]

This is a channel with great integrity.

[@damagingthebrand7387]

As long as you do not hit his seams.

[@mikecanaday1631]

American examination of German armor, specifically a PzKpfw III gave a low opinion of the choice of welding rod, but a high opinion of the armor plate.

[@adoramus]

Thank you. Great channel and great video.

[@jckluckhohn]

Learned something today thank you

[@lisandromc78]

Hah! Yesterday I was looking at the pictures I took at the Panzermuseum and wondering why the interlocking plates. Just a few hours later you come up with this video... 😲 Great work, Bernhard!

[@AJ-qn6gd]

SIRI is always listening 🤔🇬🇧

[@Anymouse6980]

I am a new viewer of your channel. I have seen your with the Chieftain. Great presentation with facts and interpretations, and indicating when your statement is an opinion. Keep the good work. I appreciate your views based on access to German source material. Thanks

[@anotherneo231]

thanks for this honest information

[@typxxilps]

that is a really great one considering all the reasearch required !

[@charlesfaure1189]

The T-34 was a horrible tank to have to fight in. The sloped armor on a relatively small vehicle was a major reason for that. The Germans went to sloped armor as their tanks got bigger (and therefore roomier for crew and ammo, etc.) Better armor protection isn't worth it if your crews can't fight the vehicle well.

[@andrewflindall9048]

Interlocking (as my original post appears to have disappeared) was an economic measure. Major joints were not plain butt joints. The machining required to rebate joints was expensive in terms of time and tools. Interlocked joints could be gas cut relatively quickly and cheaply. Jigs were still needed for assembly as tolerances were much looser, becoming shocking in some cases later on (joints needing to be packed/shimmed before welding). Chapter and verse: Final Report - Welding Design of German Tank Hulls and Turrets 1948

[@jonassackarndt1174]

I really liked the video and highly appreciate your honesty on the level of understanding you have. I was a little bit surprised to see the first part of the video and i think it is rather interesting to think about the connecting mechanisms of armor plates. I personally think it were the drivers vision and the crews and engineers being used to the layout. It is not completely neglecting sloping, it just tries to minimize the size of the visory hatch. Also it might have been an influence that the tank would effectively become a little shorter. As soon as more communication was inteoduced and also no more direct vision was required it was possible to drive without that weakspot. I really wonder if the big hatches of sloped vehicles or the vertically closing hatches of german tanks were seen as a weakspot by the soldiers of that time or as a necessary thing because driving blindly was seen as more dangerous than having a thin weakspot.

[@ianslaby5703]

Interlocking armor plates is an interesting but separate topic from sloped armor, because clearly you can do one without doing the other. About the positives and negatives of interlocking armor plates: first off, as you mentioned, thick tank armor is hard to cut (especially with the precision necessary to create interlocking), cutting it into this shape will take more time because the length of material you need to cut is longer than a straight line, the same problem appears with welding. Obviously these are two very expensive, material and time consuming processes, I think that they probably had a reason for them. I think the main benefit to interlocking the plates like this is impact resistance. Welds are generally more brittle than the slabs of armor that they join, when they get hit, they sometimes crack, even more rarely, the entire weld cracks and the structural integrity of the hull is compromised without a full penetration of the armor. I think that this is what they wanted to deal with. If a weld like the one on the Tiger II is impacted, part of the weld might crack, but the crack will only travel down the weld in a straight line, once the crack has to make a 90 degree turn to follow the weld, a lot of the energy will dissipate. This makes the weld tougher even though Germany did not have the best welding technology as you mentioned. This is of course all speculation on my part based on my limited knowledge of armor manufacture, welding, material science and other topics. If I got something wrong please tell me!

[@yuhaz]

great vid, thx!

[@ERIK-457]

I imagine that interlocking welded plate armor both spreads the stress on a longer weld line, and also the geometry itself also helps to lock the plates in place more strongly also aiding to keep the whole thing together and not relying purely on the welds, i think this was specially important for the germans at that time since their steel lacked components to increade flexibility and reduce overhardness, so with harder plates interlocking is also more effective, but also needed so the plates dont crack at the welding lines or so that the welding lines are stronger

[@VS-ff4ez]

Great video

[@Pihnes]

The interlocking welds/steel plates can also be found in warships like the Iowa class New Jersey. Basically, by increasing the surface you'll get a stronger weld.

[@MarcosElMalo2]

That’s not how welding works. It’s very different than wood joinery. In welding, you are bonding two pieces into one solid piece. The weld needs to penetrate the thickness of the metal and you need the proper amperage going through the electrode/filler rod. You are fusing metal together. In a wood joint, increasing the surface gives you more glue surface. That’s what you’re thinking of. The interlocking plates you saw more likely were to aid in more rapid construction-it would allow more rapid positioning of the plates before they were welded.

[@kirotheavenger60]

​@@MarcosElMalo2a longer weld means the two metals are joined together over a larger surface, increasing strength The mechanism might be a little different to glue, but in this regard it's no different

[@gerhardris]

Thanks for a great informative video adressing problems I also asked myself why noone answered them. I love the way you simply state what you know don't yet know and find out later. The hallmark of a trustworthy source. As a former Leopard 1 driver I too noticed the interlocking teeth way of armour wasn't continued. Albeit the phylosophy changed I guess after having lost the war to many Shermans etc. Indeed also what you mention welding techiques and steel quality come into play. As do periscopes we called episcopes due to only mirrors and no optic lenses. I also thought it might have been the room and weight considerations. Sloped armour costs a lot of space inside. The smaller the tank and relative old engines are larger and more awkward old tanks especially British ones had lumps of steel.plate to get it all to fit. So I guess it was a mix of many factors that come into play. Cost, availebility etc. So, the jury is still out on a new line for many video's of choices. And of course talented and less talented engineers or traditions in industry. Anyway, keep up the good work.❤ 16:32 What

[@maurotolari9215]

Tĥe interlocking plates gave the frontal armour more strength. There is more weld for a given length.Also, an impact by a shell presses the frontal plate against the adjacent plate ,preventing the welded area from tearing..

[@davids-ip2lr]

It takes a smart person to assume their right, but to learn more and admit they are unsure. I can always trust this channel to present information in a thought-out and honest way, without letting bias get in the way. And to be fair, the different possibilities presented in this video don't necessarily exclude each other, and more likely, both the structural integrity of welds and the need changes in needs of vision ports contributed to the use of slopped armor.

[@paulkurilecz4209]

One thought about the use of interlocking plates in welded construction. Even before the development of fracture mechanics, it was well known that welds were more brittle than the material that was joined by the weld. Perhaps this interlocking joint design was meant to limit the extent of a weld failure due to impact from a shell.

[@akk-nd3vj]

i remember reading from some book that boxy pz was cos sloping reduce space inside the tank

[@xXxTripleHxXx]

The stepped hull is also beneficial for maintenance as it allows for easy access to the transmission. Back in the day the drivetrain was not combined into a dense package that can be lifted out as a single piece instead the components were spaced out more to ease maintenance. The reason why rear engine front transmission was done Is so that both could be placed in a smaller space than what would have been needed if you wanted to put them into a single compartment without compromising maintenance.

[@jan-eric-schacht]

Writing this before having seen the video. Look at the turret of the Panzer I and you will see sloped armor. There was sloped armor right from the beginning. Maybe not as much as later, but others didn't have much sloped armor as well. Look e.g. at the british tanks including all the Vickers copies... Also with the early recon cars like SdKfz 222 you find sloped armor.

[@MannoMax]

As somebody that has to assemble large heavy parts for my day job I have another idea as to why the mortises were there: Ease of assembly. Moving large, heavy, armor plates into exact position for welding is way easier if you had those notches as a guide. This would also explain why germans did this on the "heavies", but not on the 3s and 4s, and why none of the allies really used it. If you're doing well prepared mass production of a tank, you can build welding fixtures that quickly position the plates, regardless of notches, but if youre building them at a lower volume, its easier to cut the plates with notches, instead of building an entire fixture before you can start production

[@andreimoutchkine5163]

Quadratisch! Praktisch! Gut!

[@claudiosironi7591]

Very interesting.

[@joechudleigh94]

My mate is an engineer, he builds and designs trailers. He always uses interlocking where he can. He told me that it provides good strength and shock absorption and stress is distributed equally

[@MarcosElMalo2]

Ask him about welds.

[@joechudleigh94]

@@MarcosElMalo2 Yeah sorry thats what I meant interlocking puts less stress on the welds and distributes pressure evenly. funny enough where the welds have broken (his designing a new trailer for farming) is were the parts cant interlock.

[@michaelguerin56]

Aah … the danger of asking questions, just as you start to think that you have the answer😁! Cheers from NZ🇳🇿.

[@justinbrown691]

I think you have it right. Boxy was easy and it worked given their welding abilities. Evidently, this equation changed for them fire power increased. Really interesting video and topic in general.

[@josephahner3031]

Sloping was first seen in late medieval castles soon after the development of cannons. It was first applied to tanks in practice WW1 but in theory even the Da Vinci tank had it. Though the Da Vinci tank was designed that way for structural reasons rather than for enhanced protection.

[@Nedula007]

Thank you

[@Riceball01]

The thing about German tanks and sloped armor is that German tanks from the PzKpfw III up to the Tiger did have sloped armor, at least on the front of the hull. It's just that it's not set back at a very steep angle, but it is sloped and not sitting at 90 degree vertical. If you look tonkas like the Tiger from the side or a at slight angle, you'll see that the front plate where the bow MG and driver's view port are mounted are sloping back towards the top. And nose of a Tiger is completely sloped.

[@GaveMeGrace1]

Thank you.

[@SM-xc4rl]

Betreffend der verzahnten Panzerplatten. Ich war mit meinem Großvater mal im Museum und fragte ihn nach diesen "Zähnen", sah für mich als Kind so aus. Er erklärte mir, diese Verzahnung erleichterte die Herstellung der Wanne, denn die sehr schweren Panzerplatten mussten so nicht per Kran gehalten werden, während sie verschweißt wurden. Nachdem der Kran die Platten so abgelegt hatten, dass sie ineinander gegriffen haben, konnte der Kran anderen Tätigkeiten nachgehen. Es könnte natürlich weitere Gründe geben, aber die Erklärung erschien mir plausibel. Leider kann ich ihn heute nicht mehr fragen.

[@johnvlahidis_google]

your coment is better than 16+ minutes of this crappy video thank u!

[@anthony3968]

The interlocking of the armor allowed for welding of only one side without loss of strength. The Sherman was welded on the inside and out side of the plates for strength. Dove tailing the plates eliminated the need for the extra Welding.

[@maryambintghassani2341]

You are forgetting that German doctrine for PZ III, IV and VI was to take an angled approach to the enemy guns, moving forward by alternating between 10am and 2pm positions. This means the frontal plates ARE angled from the perspective of an opponent at the 12 position. The utility of additional angling in a second plane is questionable in such a position.

[@gore0ru]

Didn't the Germans know that guns could be rotated?

[@maryambintghassani2341]

@@gore0ru I'm not sure what you mean. The entire point is the tank gun is rotated but the frontal armour remains oblique to the enemy.

[@user-gj4dd9et7j]

​@@maryambintghassani2341, yes but what about side armour?

[@maryambintghassani2341]

@@user-gj4dd9et7j A weakness, obviously, but as it would also be oblique to the enemy, it would also be less vulnerable than it appears.

[@ianmarsden6276]

Very good video, very informative. Perhaps an additional reason is that sloping the armour reduces the internal space for crew ergonomics, ammunition storage, equipment etc. Therefore if you want a tank that has the same internal space as a flat plated tank then the overall size of a sloped armour tank must increase making it easier to hit and costing more per unit in materials and man hours to construct. The Soviets got around this issue in the early T34s by having small and uncomfortable tank crews.

[@JRSimoes]

First off great video as always!! I have always supported you guys by purchasing all your books. I have every one in English. Unfortunately my german is extremely rough and out of practice. I see some books that only have german versions. Any chance you guys are working on translations into English for those? Keep up the great work!

[@MilitaryHistoryVisualized]

Thank you! Stug is being slowly being translated.

That’s the problem with history, it’s so often raised more questions than it answers. Great video as always 👍🏻

[@geronimo5537]

I believe the interlocking armor is a product of the intelligence war between the various countries and germany. Where the germans were convinced this extra step was needed for some reason. Thus slowing and complicating their production of armored vehicles slightly. It makes the most sense given the idea has completely faded away almost directly after the war.

[@ChaosWolf3]

My initial response based just on my own visual interpretations and basic understanding would be that it was related to aspects of the interiors. So the driver vision ports do make sense. One thing that has to be considered is that, while the sloped armor all around the T-34 tanks were good for protection, these sloped also limit interior space considerably, which has a negative impact on ammo stowage, crew comfort, crew capacity (sloped T-34 turrets feature a 2 man crew instead of the usual 3), and other factors that can affect crew performance. I expect this to be one of the reasons that the Sherman had sloped frontal armor, but flat sides and that the side armor being the primary stowage of ammunition in the early war days was no coincidence. I don't think there's one reason alone why Germany used box like designs until later, I think there are multiple, very complex reasons. From production to interior space and function as well as crew comfort and even compatibility (tall people were harder to fit into tanks), the list of reasons a box like design might be better is quite extensive.

[@ven7165]

What I had assumed was Germany's tanks were designed for a war that used weaker guns and designed at a time when tanks were novel and so what could/should or could/should not be done with a tank was in question, as well as the fact that a box-like design was easier to design and manufacture.

Der Disclaimer zu Beginn…mit nettem Augenzwinkern zu unseren Behörden mit den „richtigen Prioritäten“ 👍👍👍

[@toddellis8346]

I think in this, there are three different points which are getting caught up in the same topic, being: 1. Sloped armor 2. Heavier armor. 3. Effective welding of sensitive armor plate. the interlocking joins are not exclusively related to sloping armor but are more a factor relating to effectively joining the ever increasing thickness of armor. In the case of the deflected shot being turned away (action/reaction) there is also an increase in stress that must be effectively distributed through the welds . These gargantuan thickness plates cannot possibly be fully welded so the strength must be achieved by other means. Keep in mind any welded structure achieves the required strength not through the welds themselves but through correct weld placement and correct fit up before welding. With all that said, in my own opinion all the sloped side armor was largely a waste of effort, a pointy nose and vertical sides seems to have stood the test of time.

[@jpl7909]

I think the notched plates is mainly due to manufacturing and material constraints. With the notches, they can fit plates together like puzzle pieces on the assembly line before they move on to get welded. There's no need to brace the plates in position, or drill the plates and use precious bolts. I'm guessing all machining and fasteners were in short supply. Simplifying the design by not having to try and wrestle with sloping affecting internal working volume and construction complexity, especially when using already extremely thick armor for the time, was probably seen as a good trade since they were already struggling to meet demand for vehicles. Once they saw the escalation in enemy guns and munitions, sloped armor is a relatively easy way to up-armor to meet that threat. It does seem like when you can do blitzkrieg, having hyper-optimized armor is of minor importance. Later, as the army is bogged down and tanks must soak up more punishment that can't be avoided by rapidly defeating defenders, pulling out all the tricks and optimizations becomes crucial.

[@Hive-Mind-BBX]

Sloped armour is basically on every WW2 Armoured vehicle, however, it was rarely implemented into design intelligently to act as sloped armour. In fact, many of the vehicles with a lot of armour sloping in early WW2 were pre-war designs like the Soviet T-60 for example, which is a pre-war light tank design, but the front and rear armour is sloped. Additionally, most nations with tanks at the time of WW2's start, had at the very least made something with mostly sloped frontal armour.

[@harrysibben7583]

With interlocking plates there is more surface area to weld. Which makes it a lot stronger.

[@williamchamberlain2263]

Question: when hit, or when on the move over rough terrain, do the interlocks reduce/prevent crack propagation along the weld lines?

[@nathanpowell195]

Videos that show the process and challenges of reaching rigorous conclusions are better than videos that present everything as settled and tidy

[@marcelcoetzee7152]

Probably because they figured it would be easier to add more armor onto the flat designs. It didn't work with the Tiger 1 but Panzer 3 and 4 had quite a few armour thickness upgrades during the war i think. I don't think any German or Soviet designs up armored a sloped hull design during the war. It would probably be similar to the issue that happens when adding ERA to tank that wasn't designed for it.

[@Danny_Boel]

Now I am becoming interested in how exactly they welded those plates together, what did they use for consumables like grinding wheels and electrodes, and how did they procure them? AliExpres wasn't around back in the day, so did they have to produce everything themselves?

[@busterdee8228]

Interlocking might tend to support plates in place during welding, tying up heavy fabrication equipment less. As to flat plate, it seems to me that you don't have to worry so much about shot traps or chaotic deflection. Trying to hit a turret ring would seem to be more challenging.

[@xxw379k]

Interesting to hear about the backstory to the Volvo 240 series.

[@sebastianb5036]

Didn't the Tiger Handbook advise to angle the tank towards the enemy? By doing this you basically neutralize the disadvantage while still maintaining the benefits.

[@MilitaryHistoryVisualized]

That is horizontal angling, sloped armor is vertical.

[@chengong388]

Sloping increases effective thickness, but you also need a longer plate to cover the same height, which probably doesn’t weigh that much less than just a straight but tricker plate.

[@orkako]

Inclined armor was already used in the Middle Ages. Back then, the armor of knights was specially inclined so that the blows of spears and swords would slide down the armor. Subsequently, this art was applied to the construction of castles, where increasingly sloped walls were built to cope with increasingly accurate artillery weapons. Ships, too, gained sloping armor, although this was originally due to the imposed tax on the deck area, so the sloping sides resulted from the reduction of the deck. It turned out, however, that the inclined side not only allows the ship to pay less tax, but also to deflect cannon shells. The inclined armor continued in the first ironclad ships. First during the Crimean War (at that time such armor was used on floating barges) , and then during the Civil War on monitors Inclined armor can already be found among the first tanks, but there were technological problems to fully incline the tank's armor. The first problem was the visors, as mentioned in the film. The thicker the armor was, the more difficult it was to cut a proper hole. In addition, when cutting the hole, there was a risk of damaging the plate, which was already only suitable for remelting. Another problem was the complexity of the design, this lengthened the production process, production time and production cost. The thicker the armor plate, the more all these costs increased. The very process of fitting and welding the inclined armor plate was complicated. During WWI, inclined armor was not a big problem, as long as it did not exceed 45' of inclination. This was due to the fact that armor plates were riveted to a special framework. An angle less than 45' prevented riveting. It was possible to get around this by creating a more complex shape from more armor plates, but this increased cost, vehicle weight, production time and did not make the armor more resistant to hits at all. Quite the opposite. The revolution came after the war with the use of bent plates, but this worked well with plates no thicker than 15 mm. Bending thicker armor required creating wider bend arcs and special techniques for hardening steel. Even so, bent steel exhibited weakened ballistic capabilities. Even welding was not an immediate solution. Welding in the 1930s was still a fairly new technique and was not perfect. There was the problem of welding sheet metal at unusual angles, large thicknesses, and armor plates that were too heavy. The Americans developed the relevant technology only with later models of the Sherman (although they had already experimented with it with the M3 Lee There was, however, the problem of cracking welds to vibrations and stresses at that time. The Russians did not have to develop welding technology, as they received the appropriate technology from the US, as did the British. The Italians and Japanese received their welding technology quite late from the Germans and did not have time to implement it in series vehicles. The alternative to welding was cast armor. It was cheap and quick to produce, but less hard and, on top of that, without the right technology, emitted numerous fragments inside when hit. That's still not the end of the story, however, as sloped armor complicated access to the gearbox, and placing the gearbox at the rear would create numerous technological problems (the T-34 had huge problems with the gearbox. The last gear had to be put in by hitting the rod with a hammer, while the gearbox itself had a very short lifespan, so there were T-34s carrying a spare gearbox on the engine compartment vault.

[@jeremystrain1574]

Interlocking will reduce some stress on the weld.normal seam from side all pressure will be on weld.interlocking could get by with less weld at cost of more material preparation.

[@cryhavocandletslipthedogso1873]

Hey, I have a quick question and would very much appreciate it if you could answer it: Would the P-1000 Ratte have weighed around 1000 tons? Based on whatever specs I was able to find, there just seems to be no way it could have been that light with those dimensions, the Gneisenau turret and those ridiculous armor thicknesses

[@deezynar]

That "interlocking" is typically referred to as finger joints, or box joints. Cutting the notches takes more time, but they align the plates for easier assembly. It could be argued they create a stronger joint, but welding turns multiple pieces of metal into one piece, so strength isn't really improved. The only advantage I see is the help with aligning the plates for assembly.

[@vladimirpecherskiy1910]

Well, that in case if ideal welding. But when you do thick plates ideal welding is a big problem.

[@hakeemzahardi9207]

Can you make a video on German casting technology during WW2 and why Germany didn't adopt casting tank turret/hull like US and USSR

[@georgepatton93]

My guess, If you have good steel quality, you can get some good armor, slope armor is just A factor, not THE factor, not to mention slope armor can limit the space inside your tank if not designed properly

[@adlerarmory8382]

It's interesting the production economy increased due to improvements in metal cutting and welding technology. I thought just the fewer parts and seams of the monocoque style build was always the reason. (ArtieJohnson-Very interesting.)

[@major0noob]

Was probably cause experienced welders were in short supply, bet there's a lot of shallow welds on mass produced 4" plates. Bet it helped with assembly too, just lego a hull and leave it, the welders would get to it eventually and they won't need cranes and precise placement

[@josephmcdermott6837]

The question about the interlocking plates is interesting. Given how much extra work involved and waste incurred (where the cutouts create more scrap material) there must have been some clear benefit. I know little about tank design or fabrication specifically but I'd wonder would the interlock allow you to use shallower welds needing fewer passes and less time (using the mechanical interlock to take the stress of the impact rather than having to build up layers of weld to fully fuse the thick plates)? If this is not apparent in sections through the joints then I can't see any saving in manufacturing time and I can only imagine it was purely done for max possible toughness. Perhaps they thought the heat affected zones either sides of the weld would easily shear on impact and they needed the interlock to interrupt the shear line but in practical terms and with the benefit of seeing how others were fine with simple joints it seems mad particularly given the attritional war they ended up in.

[@techforge-Nate]

Square armour like the Panzer 3/4/Tiger can still be angled by positioning the tank and shooting over one of the front track wheels. If you have pike nose, or sloped armour that is angled for frontal deflection, if you are caught from the 45 degree angle to the hull, these plates are more or less flat. Early German tank doctrine also had more emphasis on mobility than protection against tank guns, which meant the square designs were adequate for that doctrine, while also remaining feasible for production as Germany were coming from a very low technical and industrial base compared to their opponents in the post Versailles treaty era.

[@bikenavbm1229]

in my mind the interlocking amour joints are a seperate design feature not really connected to sloped or vertical amour, and vision technology again a design feature compromise perhaps led in a direction by better optic development.

[@andrewklang809]

Were the Panzer IVF2-J models anything more than adequate stopgap tanks, or were they legitimately excellent designs until the Panthers were fully ready. And by 1944, were they still worthwhile to produce, or were they already outdated?

[@exharkhun5605]

The interlocking armor has to do with the surface area of the weld. It became necessary as the armor plates became thicker. Depending on the welding technology, and this was hugely different between countries back then, you weld only at the surface of the joint between plates. The interlocking creates more connecting area to weld, and thus stronger weld's. You don't need the interlocking (as much) if there's structural framework underneath or if only one of the plates extremely thick. It's main purpose can also be during construction, to hold something in place so a good weld can be made. That's why you may see it pop up situationally. After the war the hugely thick armor plates disappeared, or were created in different ways. Welding techniques also changed and improved.

[@vladimirpecherskiy1910]

Exactly.

[@CAP198462]

The point about the driver’s direct vision hatch was interesting, I hadn’t noticed that before. It’s also amusing how similar the interlocking plates look to Lego bricks.

[@freetolook3727]

Germans were convinced that the box armor was thick enough and the fact that it was quicker to build a tank with box armor rather than all the extra welding on sloped armor.

[@EllenbergW]

As quite a few here have said already, sloping your armor to a significant degree also reduced the available interior space by a significant degree. Keep in mind, that even in a high intensity conflict, the time a tank is actually fighting is a small fraction of the tank being in the field. I would assume that having a tank-crew that is fit and ready to go when that fighting time actually comes around, is much more important than having a bit more protection - this might be one reason, the German tankers could deal with the (on paper) superior French tanks in 1940 and Soviet tanks in '41. Note: I think it was the chieftain who said in his review of the Pz III, that this was probably the best tank of the early war, because, among a few other things, it's excellent ergonomics.

[@Spartaner251]

So what's the diffrence for production time in straight welds compared to interlocking armor plate welds? Because cutting the armor plate is only one step, and even then, just cutting straight might still be faster than interlocking. The other question is, what was the maximal thickness that could be welded at the time? Maybe Drachinifel could help with that?

[@patrickvolk7031]

One of the obvious (maybe oblivious) things to me about sloped armor is it increases the surface area of the armor you need. For heavy designs, and maybe due to efficiencies, the Germans opted for thicker as opposed to bigger. It may also be that when the shell was AP-C, the hardness was expected to defeat the shell. When it got to KEPs or shaped-charge rounds, it concentrated the force enough to defeat hardened armor, and deflection of the penetration path was more a thing. As far as why sloped on early vehicles, bullets on thin armor would dent it, and cause bullet spall up the face. The US was casting hull parts by the end of the war, getting rid of the welds.

[@juusolatva]

another reason not to use sloped armor is that it affects how easy it is to make use of the space inside the tank

[@vladimirpecherskiy1910]

Yes. And this is a big deal if we are speaking about final weight of armor. Naturally sloped with same thickness has more surface and weight more.

[@xt6wagon]

FT17 loved sloped armor even if it was barely armored. Another reason for the step is no one had a hull MG that worked on sloped armor early on.

[@benjammin3381]

Ive picked up, though cant recall where, that some of the reason for the boxed design were to make more space for the crew and a three man turret. And ofc because of weight limitations. Tiger "how to use" manuals given to crewmen also teach the crew to "slope" their armor by angling it. So it probably wasnt needed until guns got bigger.

[@nekomakhea9440]

You can see these jigsaw-like weld joints on warships too, USS New Jersey's youtube channel shows some of them used in battleship construction. They mention that welding is a new technology at the time, and they use a mixture of rivets and zig-zag welds because welding isn't a tried and trusted technology yet.