Battleship Armour Engineering - Why is naval armour multi-layered? 

Pinned post for Q&A :)

As a mechanical engineer for over 20 years, one thing I've learned is that you never can know enough about metallurgy.

I feel ashamed that I looked at this and thought "damn, only 20 minutes long" shout out to any other engineers who would enjoy a 8 hour seminar on metallurgical composition lol

I like the idea of showing this practical Hands-On science. I believe it'll be a great learning tool for anybody who is a young Naval enthusiast, who is just found this channel.😊

Not used in warships but some merchant vessels in WW2 which got labelled "plastic armour". After dunkirk it was realised some of the very old ferrys used in the evacuation had been surprising resistant to armour piercing bullets. Upon investigation the protection was found to due to decks being coated in asphalt. Asphalt being fairly hard gravel embedded in fairly soft bitumen. Admiralty wasn't happy with it being considered as amour, but it did get added to many merchant vessels and saved many lives. Might be interesting to see how pea gravel in tar stood up to BB pellet.

As an engineer (sort of, my work history is all environmental compliance) with a second semester of materials science, I approve of this and look forward to more. Particularly if we can ever really understand what the US was thinking when it was hardening class A armor plate for cruisers to 60-80% of the total thickness.

Me at 8 minutes in: “ooh is he going to demonstrate glueing cardboard to glass later?” Me at 15 minutes in: “nailed it!” I love the practical demonstrations that you do Drach and would love to see more.

Excellent presntation Drach, I for one would be most interested in further videos on the types of materials used in Battleshipo construction. I would imagine that there are a number of differnts steels used in building a warship, as each has properties specific to the job they are required to do.

Designers of tank armour had to relearn this lesson. They found that a soft steel inner layer much reduced crew injuries from spalling off the hard outer armour.

I'm interested - Had you ever made a video about the beginnings and the development of compartmentalization? It's a pretty important concept which contributes greatly to the survivability of ships, so i hope you had covered it already.

I think it's fair to mention that the British did experiment with using a Stiff Upper Lip as light armor to much success, but found that the additional upkeep in tea and pasties was untenable at sea especially with war time shortages.

Metallurgy is, as Yul Brynner said in The King And I, “a puzzlement.” But so is ballistics. As a curious person at the range, I’ve shot wood, rocks, bricks, watermelons and steel with rifles and handguns of various calibers. It’s always fascinating to see which ones explode melons and which ones just whiz right through, and which ones thump steel gongs hardest, which ones move the gong most and which ones actually damage the steel plates. Often the results are non-intuitive.

Drach - I heartily second/ third / fourth… the comments about more of this type of presentation. It was a good “basic” explanation of a difficult subject, complete with visual demonstrations of the principles involved. I didn’t need to be a PE to understand it, and yet it didn’t feel dumbed down. Well done.

I am 78 years old and still learning things.

Will you discuss Dahlgren’s armor penetration tests and the development of the Dahlgren gun? It’s an interesting topic I briefly delved in when discussing a Royal Navy v. US Navy pertaining to ironclads.

Chocolate is similar to armor plate. It gets brittle when cold and soft when warm. And it can be tempered.

Drach’s experiments always ramp up to the point the very planet is endangered ... I love this channel.

I liked this--the experimental stuff was great--as well as archive fotos from Bethlehem steel! Your use of cardboard as analog for teak was good--although you did call cardboard more "ductile"--where what you meant to say was "tougher." Ductility is the mechanism to achieve toughness in metal (usually) but cardboard as well as teak achieve toughness a different way--through composite properties--strong directions and weak directions etc. Interestingly, this composite effect became of great interest well past 1910! One of my graduate school professors, Frank Ko, did a lot of Army funded research on "ballistic" composites using kevlar, spectra, and many other fibrous composite materials. And of course the Army did adopt kevlar helmets--not sure if they still do that.

Really enjoyed this scientific explanation of how armor works. I liked the practical demonstrations you did to help illustrate your points. So, of course I would be for more of these videos. If you get a chance to use TNT that would be a plus. 🤣

A few more complex points concerning the differences between homogeneous, ductile plates and hard-faced plates: (1) Hard-faced plates (Harvey, KC, Compound, Chilled Cast Iron) are penetrated mostly by velocity, not the shell weight. That is, the weight term only increases by the 0.2 power (small) but the velocity effect of increasing thickness penetrated goes up with the 1.21 power (if damage to the shell kept the same for all hits). (2) For homogeneous, ductile plates (Mild Steel, Nickel-Steel, Krupp Chromium-Nickel-Steel, RHA, Non-Cemented Armor, Class "B" Armor, Special Treatment Steel, etc.) between 0.2 and 1.1 caliber thickness, the French 1890 De Marre Nickel-Steel Penetration Formula gives rather good penetration values (again, when shell damage kept constant) at right anglesd (not as good at other angles of impact) -- intertwines US Naval Proving Ground Dr. Hershey's WWII test data) using a De Marre Velocity Coefficient of ~1.22 to change from nickel to nickel-chromium armors. (Below 0.2 the plates have large dents or "dishes" form on impact and above 1.1 the hole made is by the shell nose "wedging" the armor sideways, while in the 0.2-1.1 region the shell nose forms small dishes, only wedges near the face of the plate, and forms thick triangular backward-bent triangular "petals" ringing the back of the hole (broken off much of the time). Here the total kinetic energy of the shell using both weight and velocity work in unison. So we get penetration proportional to [(weight) x (velocity-squared)] to the 0.714 power = (W)^0.714 x V^1.43. (Note that this velocity power is exactly double the penetration increase for all face-hardened plates. Interesting.) (3) The hard face of face-hardened plates is brittle and breaks apart as it is punched through the hole and out the soft plate back shock-absorbing region. The thicker the face layer, the greater SCALING sets in to make bigger shells hitting proportionately scaled-up plates of identical properties penetrate more and more easily. Krupp originally used a 35% hard face and this had only a relatively small scaling effect weakening the thicker plates against bigger shells 9yet afain, with constant damage). Thinner faces do have less scaling, but the difference is not large. Going OVER 35% rapidly increases scaling, to the detriment of armor being hit by larger shells, though against small, cruiser-sized shells, the scaling is always small and works to make such shells penetrate better, not worse. Italy's Terni Company seems to have figured this out and had its thick plates have thinner proportional faces -- one thickness in cm -- than its thin plates. US WWII "Thick Chill" Class "A" face-hardened armor had a 55%face to try to damage the superior US WWII AP shells and this degraded this armor's resistance against the larger AP shells, though it was still stronger than US WWI-era Class "A" armor.

You sir are an excellent teacher. I knew some of the reasons behind compound armour, your experiments demonstrate for even beginner's. Well done!

More of this? Not going to lie, it would be great!

Best form of advertising is what you did at the start. Normally I avoid ads, but yours was pretty cool. That is exceptionally rare for me to say BTW. Maybe a first. Good Job.

This genuinely taught me something. Like yes I know naff all about military history (or didn't until I started watching this channel) but this is something so simpler and so cool that I now I know and I like how you actually demonstrate things.

Fascinating presentation for a layman. Thank Drach.

104,000 views of this show about armor to me is amazing. Shows how focused your subscriber base is to your shows. Amazing! Have a Magical Day and Great 2024

As a fellow engineer I salute your efforts, especially under the circumstances in the UK concerning rifles 😊 Yes Drach, please do investigate this matter further!

Pedantic correction: wood (and to a lesser extent carboard) isn't ductile. It doesn't plasticly deform much at all and doesn't strain harden. Instead it bends until it breaks suddenly, like a spring. For a true ductile material (like lead or copper), you'll see the material inelastically deform by a large amount. This means that, once deformed, it doesn't come back to true. But it van deform a lot before it breaks.

Fort Nelson NR Portsmouth is the home of the royal armorys cannon and big gun collection and they have a giant plate with some impressive holes in it .10inch thick about 6ft sq with lots of shots taken at it from different angles.worth a look at the whole museum as there's a battle ship cannon on the front lawn (as of a couple of years ago)

5:28 I thought ductile was a type of building materials used by aquatic birds for kitchens and bathrooms

I would have loved to see follow up shots with the plastic BBs on the damaged composite armor.

Absolutely fascinating presentation. Thanks for showing the process and progression of damage management.

Loving the format, topic and style. Thanks, Drach!

Oh boy, this is going to be hideously technical! Sign me up!

Outstanding presentation Drach! Thank you.

Timber backing is convenient for damage control, and just fixing to it generally in addition. Thank you for the demonstration.

Thanks Drach, great segment. You did a awesome job with your substituted materials. 👍👍

Excellent Video. Very illustrativ to actually see it in done in the model. Thank you

15 min? Duck tile?.....hard to get them feathered suckers to stay on the hull where you put them.

I love that you showed a practical example, im famillar with the concept is pretty good detail but it was alot of fun to see tested with such an easy thing to replicate

The practical demonstration was fantastic! Would love to see more in the future.

Yes please more videos on this topic!!

Yes indeed these are some of my favorite of your videos, and please don’t hesitate to make them extremely long.

Fascinating analogous practical demonstration of the principles of armor protection. Would definitely like too see more!

This was a very effective demonstration. Well done!

Another great video. Great demonstration of practical material science and the complexity that exists in even the simple situation of trying to poke holes in a flat plate. More please

Excellent video, thanks Drach

I, for one, would love this sort of practical and visual demonstration of the engineering behind ships. Thanks for the entertaining and educating video!

Absolutely want to see more! Keep it up, Drach!👍

Drach, loved this video! Keep them coming. Also hoping that you and yours have a lovely Christmas season

Really enjoyed this one !!

Really enjoyed this video. I have watched many videos where they say x type of armor was used but never explained why. Very nice to finally know. Keep up the great work!

As a lifelong Pittsburgher who’s grandfather fought on Saipan and worked in the mills, rather proud to see so much Pittsburgh made iron being used. We are called iron city for a reason.

Great vid, would watch more of this!

Fascinating stuff! I love practical science demonstrationsas it really helps people understand exactly what's going on in a way that descriptions can't.

I love these practical videos. I loved the age of sail food video as well!

Brilliant, Drach! More of this type of video would be very welcome and most enlightening! 😎

Great video, informative and entertaining, more like this please!

I always enjoy a practical demonstration.

Love this engineering stuff!

Brilliantly well done

Well Done! Eagerly await a second part.

Same idea as the laminated safety glass in the front windshield in automobiles. Fascinating video.

I for one would very much enjoy seeing the development of armour. And thank you for explaining in both a visual and a oral manor, it helps a non-engineer understand. Thank you for all your effort.

Love the experiments!

Excellent demonstration! I really feel like I understand the inclusion of wood backing now...turns out holding the armor plate together is a really valuable function! And it's probably much more effective at stopping splinters (rather than generating more) than I thought.

More please,well done!

I really enjoyed this practical demonstration. Thanks and cheers 🍻

This was great! Thank you.

Well done. My vote would be Yay, to continue along "anything to do with the naval experience of the era" presentations.

Yes, I like it’ll the deep dives into armor and how it works! TY

I think you win the most words to explain something for this week.

Great video, waiting for more

Your films are awesome!!

Fascinating! I wouldn't of thought those materials would show results!

I like that the Squarespace sponsorships double as a tutorial.

Thanks for employing the physical demonstrations.

Yes, I did enjoy that very much. I have been familiar with the material properties of iron and steel since my university days, but it's always fun to see ballistic tests.

Very interesting Thanks Drach.

Very interesting and well presented. Thank you.

Yes please, more like this!

very informative. More please!

Excellent presentation, thank you.

Great video, I look forward to more like it. Thanks

Thank you for this very informative and entertaining video. I will happily watch you break pain of glass with projectiles, so bring it on dude!

Totally down for more of this

Something that tank nerds talk about is triple-hardness steel (THA) - steel made from explosively bonding or rolling a very high-harness steel (~500BHN HHA) between two sheets of normal RHA. This is very tricky to do for various reasons, but can in theory create a structural steel that is much more thickness-efficient than normal RHA. The rough naval equivalent would be rolled compound armour - where cast iron was poured between two wrought iron sheets and then rolled. I think that it might also have been possible to chill the two outside sheets and get a slab of chilled/white iron between two pieces of wrought. The advantage of a triple laminate structure like this is that, if you're cunning, you can use both the front and back face to support the brittle interlayer and almost completely stop crack propagation. The disadvantages are things like complexity, cost, constraints on what sort of steel you can use (due to changes in size from quenching) and limits on the ultimate thickness that the plates can get to (from memory, modern THA can only be made about 50mm thick). All this is probably what kept the technology from being explored further in ships, and limits the use in tanks to this day.

OKay this was interesting. Yes I liked it... it was a good explanation for armor and why there was a backing. Please continue to do these please!

YES THIS WAS VERY INTERESTING

Drach demonstrating naval armour technology using household items. Simply AWESOME!

I'm genuinely impressed at how well that cardboard/ glass demonstration worked 😀

your channel is the greatest, cheers from Florida, Paul

Another excellent video. one of many.

Woooo! Perfect mid afternoon uplift :)

Well, I enjoyed this very much. More would be welcome.

More of this please.

Solid! Top KEK! Peace be with you.

Now I get it. ... outstanding!

Awesome video! Look forward to learning more things like this! I'm also curious what the process of making the different types of armor (like how was the process for Harvey armor different than Composite)!

Drach does failure modes, rather better than I recall from student days!