Questions on extended belt/deck and AoN armor

[tycondero]

Hi all I'm new to this community and game. I was wondering could someone explain to me the idea behind extended Belt/Deck armor mechanics? What is the purpose of this additional armor? Also All or Nothing armor (AoN) doesn't allow extended armor. Isn't that a problem for armor defense?

Thanks a lot!

[akosjaccik]

Ooh, that's a touchy subject, people are currently having a rather interesting conversation about distributed armor vs. AoN scheme in this topic.

Esentially the idea of "extended armor" arrives naturally from earlier designs, as one could argue that the original idea was to kind of armor the entire ship. This either came organically (one could pick the Gloire or the Warrior even) or deliberately (thinking about the ships near Tsushima), as armour piercing technology was not standing on the point just yet where it maybe had the upper hand over armor. "Free" armor weight thus could be distributed to other sections, but emphasis can still be put on protecting the vitals of the ship, so the engines and magazines, and also the steering to some extent, and most other areas generally on the waterline got some form of armor of thinner plates - hence Belt-, and Deck Extended. They may not protect against battleships' main caliber shells, but heavy ordnance at this time was somewhat unreliable, small in relative numbers and had abysmal fire rate anyway, and so armoring the outlying areas of your ship against mid-calibers made sense. Compartmentalization and damage control isn't very advanced for these pre-dreads, so if you do not armor these areas, you might suffer considerable flotation damage.

As time goes on and AP starts to reign free, you get to the point combined with advanced damage control, where a few shells in the bow or aft do not compromise you seriously, but you want to do all you can to protect your capability to fight safely (magazines, turrets and barbettes) and move (engines and rudder) to put it simply, most other things are of secondary importance, because "they will penetrate anyway, so why waste the effort?" Argument can be made that armor that can not protect against the shell may still arm it, and without it you might suffer "just" a passtrough hit.

Combine this with the advancement in fire control and gun elevation angles, and due to the long-range gunnery the belt armor gets somewhat less spotlight and the deck armor more (as with RtW2's aviation, I expect this trend to be even more significant). Suddenly, you have AoN armor, and again, people argue over what that exactly is and how it is more advanced or suitable for the time, but probably the basic idea behind it is like this:

Classic configuration: "We are up against some heavy guns and a metric ton of relatively quick-firing medium caliber guns often even firing HE at short-ish range, better armor everything, especially where water can be a problem!"

AoN: "We are up against fairly precise heavy AP shells arriving from long range, we need all the effort to stop those and keep the ship in fight. As long as the citadel is intact, we should be fine!"

Esentially I see one or the other not "better" but a natural development when asking "what are we up against and in what circumstances, so what do we need to keep the ship in line?"

In general, I can suggest that you take a look at your Gun Data in Ship Design - there you will see penetration values according to your current tech level at various ranges regarding the deck and belt based on impact angle. This can help you tremendously to decide how to (against what to) armor your ships at a given range, although do keep in mind that the AI's tech level and construction ideas both in calibers or AP shells etc. can differ. Then again, most of the hits won't arrive under the ideal scenario either.

Some other tip, the game sometimes uses these armor values at other parts of the ship I can't remember off the top of my head, maybe Belt Extended has something to do with uptakes and such for example, maybe worth looking it up. Finally, the game uses some sort of "equal armor thickness" in it's calculations, meaning that advancements in armor quality (Harvey, Krupp cemented etc.) lowers the weight needed to reach 1 inch of "equal protection", so you don't have to worry about having data about 12 inches of protection on an enemy ship, but that armor plate stops your AP qualified for 13" based on your own shooting tests against your own, inferior plates.

[bcoopactual]

Welcome to the forum tycondero .

akosjaccik 's explanation is excellent.  

Here is a picture of the general coverage of the different armor designations used in the game.  It was made by galagagalaxian .



The extended areas of the deck and belt armor protect the the areas fore and aft beyond the main gun turrets as well as the area of the hull above the main belt.  Everything inside that is generally considered the citadel because that is where the magazines and propulsion machinery is located. 

In-game, belt extended armor does indeed protect the intakes.  I'm not sure how their protection is determined with the AoN concept in-game.  I'm assuming it's a percentage of the belt armor value but the developers, to my knowledge, have never officially stated that. 

One of the benefits of the AoN concept once you have researched it is that it provides additional protection against flooding based on the armored raft concept that was developed as part of the AoN scheme.  Since the ends were going to be unprotected it would have to be assumed that battle damage would cause one or both ends of the ship to flood.  So the designers ensured (to varying degrees of success) that the internal volume of the protected areas in the citadel had enough buoyancy to keep the ship afloat even if both ends completely flooded.  So, in-game, AoN schemes have greater resistance to progressive flooding.

In general, with AoN since you don't need to have armor on the ends, the belt and deck armor thickness will be greater than a non AoN design that you have to armor the ends. Personally, when I've transitioned to dreadnoughts but haven't researched AoN yet I'll put 2.5 inches on the ends to protect against splinters and oblique shots.  More than that starts to provide diminishing returns because of the weight required.  
    

[tycondero]

Thank you both for your clear replies. Now I understand a bit better where these different armor types come into play. A question: does extended belt btw overlap with belt armor? To me it would seem that extended belt is mainly the hull of the ship above the waterline.

Also to what extend does choosing the option of narrow belt affect protection? It reduces it of course, but does it have a lot of impact in practice?

[bcoopactual]

I believe, and I'll have to do a bit of research through Fredrik's posts but what happens when a shell strikes above the main belt varies. If I remember, older, distributed armor designs had an upper belt region above the main belt. Then above that would be the casemates for the secondary guns and then above that the ship's superstructure. I believe the upper belt is rolled into the belt extended value. So the shell could strike the belt extended armor, the secondary armor (casemates), or it could strike the superstructure.

For all-or-nothing designs the hull above the belt is essentially superstructure for purposes of damage and hits tend to be called as such in the logs.

I'm not 100 percent certain of the above. If one of the other regulars is more familiar with the topic and has a better answer I'm sure they'll step up to help.


Some people have tried using a narrow main belt with an equally thick extended belt. It seems to save some weight. Supposedly, there is a risk with narrow belts of the shell missing armor entirely but people who have tried stated that they didn't notice it happening to a significant extent. I know the forum member that I first heard of the idea from tried it and said it seems to work with very little downside but he quit using it because it's essentially an exploit or gaming the system. I happen to agree with him but it's a single player game so no harm no foul if others want to take advantage.

[Edit - I just realized I didn't really answer your question. The manual states that a narrow main belt means an increased chance that the shell will strike the extended belt (i.e. upper belt) or miss the armor altogether. Like I wrote above, the latter doesn't seem to happen very often but I can't tell you for sure from personal experience because I never use it. You don't normally have to make those kind of design sacrifices as the USA which is what I normally play.]

[dorn]

Jan 18, 2019 6:53:38 GMT -6 tycondero said:

Thank you both for your clear replies. Now I understand a bit better where these different armor types come into play. A question: does extended belt btw overlap with belt armor? To me it would seem that extended belt is mainly the hull of the ship above the waterline.

Also to what extend does choosing the option of narrow belt affect protection? It reduces it of course, but does it have a lot of impact in practice?

It is nowhere said however it seems to me that with narrow belt if you look at picture above the armor should not going so high in ship, the low edge of armor is higher and the high edge is lower. This means that some shells that would hit main or extended part of belt with normal configuration could hit either extended belt instead of main belt or completely bypass the armor. On top of that you can get edge belt hit which could be dangerous.

In game narrowing armored belt decrease main belt about 20 % and extended belt about 25 %. The effect is that you save tonnage with some risk. Sometimes narrow belt is used with armor scheme that extended belt is almost same thickness as main belt. It makes forward and aft parts of ship armored same as the citadel however you compromise ship protection on some lucky hits.

You can look at picture bellow. It is Rodney armor scheme.  As you can see if shell hits Rodney just at waterline with some angle, it could completely bypass armor and hit internal parts of the ship.

Even if the shell hit Rodney almost horizontally it could still bypass Rodney armor as ship move in water and roll.

Rodney armor scheme

If you look on picture bellow it is armor scheme of KGV class battleship and Bismarck class battleship from wiki. As you can see armor is going much lower bellow waterline so even if ships roll they are still protected by armor as opposite to Rodney.

[director]

Another consideration is that ships ride considerably lower when fully fueled and supplied, or when additional equipment is added. HMS Hood was one notable case; she rode so much lower than her designed load-line that the quarterdeck was often submerged. Her officers referred to her as the largest submarine in the Royal Navy. What lowering her armor belt by several feet did to her defensive power is debatable but cannot have been good.

[abclark]

Jan 19, 2019 0:41:10 GMT -6 director said:

What lowering her armor belt by several feet did to her defensive power is debatable but cannot have been good.

I would argue that lowering the belt (by itself) wouldn’t have been a big issue. She probably would’ve been better protected against very near shorts. The consequent lowering of the armored deck would’ve been a much bigger problem. Flooding above the armored deck was a big part of what caused Kirishima to capsize. While Hood was probably much better subdivided above that deck, likely damage to those compartments would’ve compromised that.

[director]

abclark - My supposition is that, if a shell is most likely to strike within a certain vertical distance from the waterline, lowering the belt makes it more likely that the shell will pass over the top of the belt. The slightest drop of its arc would them put it into vital areas. I quite agree that flooding over the armored deck contributed to the loss of Kirishima and likely Hiei - and would have been a danger to any ship of similar vintage.