An explanation of "turtleback armor"

[fnord_disc]

The release of the German battleship line has resurrected this age-old issue, and I feel like even many reputable personalities have a defective understanding of what exactly this is, although they seem to understand perfectly well what it does in battle. Perhaps this topic can clear up some inaccuracies and misunderstandings.

 

To repeat the common explanation: "turtleback armor" protects your citadel at short ranges.

 

How does this happen?

 

Ships with such a protection have an additional angled armor behind the main belt which deflects shells that are fired at the citadel area at close ranges. Below is the example of SMS Bayern with such a shell trajectory.

 

 

The angle that the shell hits the internal 80mm citadel armor at is ~27°. The auto-ricochet angle in World of Warships is 30° for all battleship guns. Therefore the shell will bounce from this armor belt and detonate in the casemates for penetration damage = 33% of maximum.

 

Turtleback armor is not a matter of armor thickness, strictly speaking. The internal armor belt needs to fulfill two criteria:

 

• It needs to be angled so steeply that it autobounces shells
• It needs to be thick enough to not be overmatched

 

Is angled internal armor rare?

 

Contrary to what is being claimed, this angled internal armor belt is very common. Below is an example of Nagato, a ship known for being not hard to citadel.

 

 

Clearly Nagato also has an angled armor deck above the citadel and it has about the same thickness as Bayern's. However, the shell strikes this armor deck at an angle of ~49°. This is not enough to auto-ricochet and the shell will penetrate it if it has enough penetration left (definitely the case at short range) and continue into the citadel area for 100% damage.

 

The same applies if the ship has a very thin internal armor deck which is overmatched by the relation armor<caliber/14.3. Even an angle of less than 30° will lead to a penetration and citadel damage.

 

So, is Nagato's citadel armor useless?

 

No. Angling the ship also improves the angle of the internal deck. If Nagato is angled 35°, the main belt will not bounce shells, but the impact angle on the internal deck is now 20°, not 47°! Since 20° < 30°, this will lead to a bounce on the citadel armor and standard 33% penetration damage above the citadel in the casemates.

 

This mechanic is the main reason why angled German cruisers (which have a turtleback as well) can be difficult to citadel through the belt and need be overmatched through the bow. Their turtlebacks are not angled enough to bounce broadside shells, but they will bounce when angled. Some exceptions exist like Königsberg - the turtleback is only 10mm and is overmatched even by 152mm guns.

 

Hopefully this will thin out some misinformation.

[ColonelPete]

The question is:

Do Friedrich der Große and Großer Kurfürst have Turtleback armor?

From what I heard before the release, they do not. Which does not make any sense, since all other german BBs have it.

[fnord_disc]

The question is:

Do Friedrich der Große and Großer Kurfürst have Turtleback armor?

From what I heard before the release, they do not. Which does not make any sense, since all other german BBs have it.

 

They do.

[lafeel]

As a side note, this is also why the Imperator Nicky can be such a pain to pen as she uses the same armor type.

[Darth_Glorious]

The question is:

Do Friedrich der Große and Großer Kurfürst have Turtleback armor?

From what I heard before the release, they do not. Which does not make any sense, since all other german BBs have it.

 

According to what I gather from Chinese forums :

- FDG has turtle-back armour but its thickness is 30 mm less than Tirpitz one.

- GK doesn't have turtle-back armour but its citadel is well hidden underwater and covered with strong armour . You have something like a Colorado which does not have turtleback armour either but still resists to citadel hits at close range. For comparaison, the case of Colorado you have 25 mm (outerlayer) + 318 mm (underwater belt)+ 85 mm (citadel armour)...

[fnord_disc]

The thickness of the turtleback is not very important as long as it isn't overmatched. The angle is much more important.

 

God, the armor viewer can't come fast enough so that these silly discussions end.

[Diminios]

 

God, the armor viewer can't come fast enough so that these silly discussions end.

Only a month or so to go, if the rumours are true and WG sticks to the same release cycle we've seen recently.

[SmartassNoob]

I think I can remember reading somewhere that "turtleback" was suppose to be some kind of extra thick horizontal armor that was suppose to protect from very long range fire that hits at a steeper angle from above and completely misses the belt. I guess what I read was complete BS then.

[Unintentional_submarine]

And time for some extra visual aid:

 This is Dreadnought herself by the way. While a transverse cutout can tell you something, it doesn't really tell the entire story. A picture of the armour as it looked without the pesky superstructure and upper decks, I think it is pretty obvious where the name for the armour comes from.

 

 

[lup3s]

thank you for the information

 

[Z_OnkelE]

Nice one! Where is the "request sticky" button for it?

[puxflacet]

yeah. this turtleback armor hoax...people, you probably mean belt armor. thats where german bbs shine

[LeeQuid]

 

GK definitely has the turtleback armour.

 

Here, at the beginning of the video, Flamu perfectly demonstrates the effectiveness of the turtleback.

See how he one-shots 2 yamato's and a montana, and then does only 30% dmg to a Kurfurst thanks to the turtleback armor

[puxflacet]

nvm...cant see the video right now. will see later what amazing things flamu discovered

[Surmaaja]

Back to the topic:

This info is all nice but how does it affect gameplay? Should I aim broadsiding German BBs differently as I'd do against other BBs?

Can I afford to show my broadside in a German BB in close range engagements?

[Darth_Glorious]

Back to the topic:

This info is all nice but how does it affect gameplay? Should I aim broadsiding German BBs differently as I'd do against other BBs?

Can I afford to show my broadside in a German BB in close range engagements?

 

In close range you aim a little higher above the waterline to the maximum possible of normal pen hits (50% max dmg)

Or you keep the distance (12-15 km) to put plunging fire on the deck. Sometimes you can get citadel hits with it.

[159Hunter]

Nice information, thx

[Poster_2015]

Actually I could get some citadels at Tirpitz at short range (no idea about FdG and GK - havent fought them enough), by aiming quite high above waterline (upper half/middle of hull) with shells hitting under turrets. I assume it was because i was penetrating barbettes for turrets. It wasnt by any means always, and hitting exactly there is a lot harder then just aiming below smokestacks, so its still a big advantage for germans, but its definitely not impossible to Citadel them.

[Darth_Glorious]

Actually I could get some citadels at Tirpitz at short range (no idea about FdG and GK - havent fought them enough), by aiming quite high above waterline (upper half/middle of hull) with shells hitting under turrets. I assume it was because i was penetrating barbettes for turrets. It wasnt by any means always, and hitting exactly there is a lot harder then just aiming below smokestacks, so its still a big advantage for germans, but its definitely not impossible to Citadel them.

 

There are spots under turrets 2 and 3 are not protected to citadel hits even as close range...But you still need a lot of RNG to do that because those spots are small.

They can be applied to FdG and GK. 

[fnord_disc]

Back to the topic:

This info is all nice but how does it affect gameplay? Should I aim broadsiding German BBs differently as I'd do against other BBs?

Can I afford to show my broadside in a German BB in close range engagements?

 

What DG said is correct. You won't hit the citadel anyway, so you have to make sure that at least all your shots hit. Aim between the waterline and the deck. That will give you a full salvo of penetration damage (33% of shell damage). If the GK is low on HP, the casemates are depleted and you will do less damage than that, though, so don't expect to one-shot a 30k HP GK.

[triumphgt6]

I like the picture of the Dreadnought - that really show the principle. On the use of English, surely a word is designed to elicit understading and turtleback does just that - the inner armour of the Dreadnought resembles the back of a turtle shell more than anything else I can think of. Certainly not anti-German - the ships they built were superb - luckily for the British, they didn't build nearly enough!

[Z_OnkelE]

This is a great and educational thread. I really hope you stop derailing it with this language nonsense regarding a problem only a few of very, very few people actually mind.

[RogDodgeUK]

Discussion about the proper use of the word 'turtleback' ends here and now. Numerous posts have been removed. Anyone found derailing this thread again will be dealt with. Stay on topic, stop the arguments and abide by the forum rules.

[thewildgam3r]

This thread explains it well It works the same way as Sloped armour in World of Tanks but its internal so you cant see the slope

 

It reminds me of how the t26e4 super pershings frontal armour is laid out using multiple layers of angled armour to minimize penetration  this cleared it up for me...TY OP

[Ferry_25]

Have been somewhat slow to react to this post. Thanks OP! I had heard of it but now I truly understand the mechanic. 1 q though: maybe it's only my feeling but why does a citadel seem to hurt much more on German BB if it gets overmatched??