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Okay first off I am no expert on naval gunnery or naval armour. I've already seen multiple people here on the forums display levels of understanding that go far beyond my own, but the issue must be raised and I have seen no one else do so fully yet, so here goes. We need to talk about plunging fire. Historically, ship designers operated within a system known as zone of immunity, or IZ for short. To put IZ in the simplest of terms, a ship's vertical armour (the belt) would be specifically made to resist all shells of a certain calibre up to a certain range and beyond, fx. the Iowa class was designed with a 12.7" belt which was designed to resist 16"/45cal gunfire at ranges exceeding 18,000m, giving her an "inner" zone of immunity limit of 18,000m. In contrast to this, the deck armour would be designed to resist gunfire at certain ranges and below. Again using the Iowa, this would be a 6" main deck plate covered by a 1.5" 'fuze-deck', which was specifically there to set off a given shell's fuze and have it explode before or on contact with the main 6" deck. This 6+1.5" deck theoretically gave her an IZ of 30000m and below against the 16"/45cal. An interesting sidenote here is that this IZ is calculated for the guns of her predecessor the South Dakota class, since for a large part of the design process these were the guns she was expected to carry, and so in contrast to most ships, the Iowa does not actually have an IZ against her own guns readily available, which would otherwise be the norm... but I digress. What's important to take away from this is that a given belt thickness renders you immune to direct fire at a certain range and beyond, whilst deck armour gives you immunity from plunging fire at a certain range and below. The space between your belt's immunity and your deck's immunity is your overall zone of immunity, where neither direct nor plunging fire can penetrate the deck or the belt of your citadel and cause catastrophic damage. You can still take superficial damage of course, but your vitals will remain untouched. What amazed me so much when I began playing this game was that for the most part, this system seemed to be the the core functional armour mechanic in use in game. Give a ship enough belt armour and it becomes immune to direct fire. Give it enough deck armour and it becomes immune to plunging fire. Excellent! But I've been playing for a while now, and have read up a lot on actual armour values from real ships as I played, and it quickly began to strike me just how disproportionately heavy you had to make your deck plates before the desired immunity zone was achieved. Again with the Iowa example, 7.5" total seemed adequate up until the very limits of realistic spotting capabilities, yet if I replicate this in game, even a twelve incher will go right through that at combat ranges going all the way down to 20000m. This unsettled the historical accuracy enthusiast within me, and so I began to run some tests. First, I took things to the extreme. I observed that most naval designers IRL went for a IZ of between slightly under 20000m all the way up to 30000m, and decided to use this as my main parameters for testing. So with that in mind, how thick a deck would you need to create a plunging fire zone of immunity up to 30000m for the biggest guns in the entire game, the mighty 20" with super-heavy shells. Thankfully, the game tells us! Thx devs! So the first image at the bottom of this post is the armour pen data for the 20" Mk.III (latest available) with super-heavy shells (tube powder). As you can see at 30000m it penetrates a whopping 60.1" of total deck armour equivalent. by applying the max allowed bonuses to our armour in game, we can bring it up to a 118% increase by equipping both krupp IV and all-or-nothing armour on our ship. This leaves us with 60.1/218%=27.5" of real deck armour. Mind you the turret face of the Yamato was only 26", and that was designed to resist 18" guns at point blank range... so a number above this must surely be far off... yet when I tested it, it bore true. You literally need to put 27.5 inches of deck armour on your ship to resist these shells at 30000m in the game... So there goes the first bit of realism straight out the window, and let me show you why. Let's step away from the Iowa for a second and instead go with the Montana, since she was in fact (and in contrast to her predecessor) rated with an IZ against her own guns, the 16"/50cal Mk.VII. According to wikipedia her belt would have been 16.1" and her decks 2.25" upper and a 7.35" main deck in the same fuze activation arrangement as the Iowas, and contemporary engineers concluded that this gave her an immunity zone between 18000m and 31000m against the improved firepower of her 16"/50cals. Now compare this real world data to my experiment. 2.25+7.35 inches of deck armour (a total of 9.6 inches) could resist 16" super-heavy shells at 31000m. In game however, a 20" SH shell requires 27.5" to stop. That's a threefold increase on the part of the armour required, but only a 1.75 fold increase in shell weight (1928kg vs 3418kg on the 16" and 20" respectively). Let's now scale the experiment down to match the montana's characteristics, by taking the 9.6" figure, running it through the 218% amplification and netting your 20.9" of effective thickness and testing it against the 16" SH shells available in game, you find that it only resists plunging fire from around 18000m and below (rated at 19.3" equivalent pen at 17500m) Which means that if you made the Montana in-game, her zone of immunity would be between 18000m and... well... 18000m. In effect there now is no zone of immunity at all, since plunging fire in-game is somehow just extremely overpowered compared to real life, to the point where an armour protection rated for 31000m doesn't even start to become effective in-game before 18000m, almost half, and incidentaly also almost the exact range where her belt armour would cease to be effective IRL. This is of course very disappointing. The game handles extremely well and feels very realistic in close quarters engagements between cruisers and destroyers, but once you scale it up to battleship sizes the lack of realism on the part of long range gunnery and penetration values just straight up breaks it for me. But being the pathologic guy that I am I decided not to bother and simply up my deck armour to the point where it would artificially create the desired zone of immunity effects, with hilarious results in hidsight. I started regularly designing my battleships with, say, a 14" belt but a 16" deck to achieve the armour protection and IZ of for example the King George V, but then the patches giving severe weight penalties on bulkheads came along and I had to sacrifice more and more vital design features to keep my decks artificially efficient, to the point where my ships had no rudder upgrades, no turret rotation upgrades, barely any torpedo protection, not a single secondary gun and literally 0" of armour on the belt and deck extended, whilst still costing two to three times as much as their historical counterparts both in money spent and weight required. All this of course always fell flat as soon as these designs came up against something like an H class, whose 20" guns still required those ridiculous 27.5" of deck armour to survive at combat ranges. But then during my recent tests after patch 11 I noticed something. I was having a fight with a 15" armed battleship in my own battleship equipped with 14.5" of deck armour, and right around where I calculated that my deck armour would start to become sufficient against that armament, I noticed that shells where hitting my deck and giving me the "penetration" counter, but the damage incurred would be almost comparable to an over-pen. Instead of 90 dmg, I got around 20 dmg, and I immediately likened this to a shell penetrating the upper fuze deck to explode against the main deck, causing limited damage as compared with a "full" penetration. I don't know if this is intentional, but regardless I must highly encourage it. This perfectly simulates the kind of damage a battleship with a separate fuze and main deck would incur at combat ranges. Still enough to be significant, but not enough to be fatal, and this is exactly the kind of protection such armoured decks would have allowed for. The shell still detonates inside the ship, but outside the citadel, causing only moderate damage. Perfect! Now make this universal. Make it the norm, rather than a freak incident that only becomes apparent after 20 test runs. Any hit on a main deck of 8" or thereabout should produce this kind of damage below 30000m, and there should optimally also be choice between going for a single thicker deck plate which might deflect all shells, but which in turn takes all the damage if indeed penetrated, and instead choosing two separate decks which only limit the damage done above the second deck at certain ranges. Secondly, we also need to talk about bulkheads (again). My main issue with bulkheads isn't that they're too heavy or too light, my main issue has to do with simple physics. I ran some more tests, and it appears that a battleship of 109000t displacement has about a 90% chance of receiving over-pens rather than actual pens on unarmoured sections of the hull with max bulkheads, meaning that when a battleship grade gun hits the extended deck (which for test purposes was left on 0" thickness) the shell goes right through and does next to nothing. If this experiment is then repeated on a ship with low bulkheads (anything from many to minimum) the shell almost always penetrates and does full damage. I find this confusing. Logically, the less bulkheads you have in the way, the higher the chance of over-pens, because once a shell strikes a bulkhead, it tends to detonate, since those are heavily armoured, often as heavily as the main belt of the ship in question. Instead what we get is the lower the bulkhead setting, the higher the chance of shell detonation as opposed to over-pens. Again, what am I missing here? Shouldn't a hull saturated with heavy and numerous bulkheads be more rather than less susceptible to in-ship detonations on unarmoured sections of the ship? Again I'm not a naval designer so if I'm coming off as a rough plebeian who doesn't know what he's talking about then please put me in my place and tell me why, it just doesn't seem logical from where I'm at. I find it especially problematic since with the above mentioned mechanics of bulkheads in relation to pen-over-pen dynamics, maximum bulkheads are essentially a necessity that you cannot in good faith downgrade on and still consider your ship competitive. They are now extremely heavy to field on your ships for sure, but the current mechanics surrounding them still makes them an absolute must, and so I find that all my designs are now exercises in how to still make a semi-competent ship around the key feature that is maximum bulkheads, sacrificing everything from firepower to speed to armour (especially deck armour) to keep this essential feature, often ending up with ships that are twice or thrice as heavy and expensive as the ship I'm trying to replicate, either because I had to give it triple it's historical deck armour to give it a similar long range protection characteristic to what it historically had, or by simply sacrifing the extended armour entirely and hoping for maximum bulkheads to give me those over-pens rather than full-pens. So I was wondering, will this be adressed at some point? Is it intentional that deck armour is currently two to three times less efficient than it was historically? Is there a counter to this that I am just not aware of? Are bulkheads just going to be continually nerfed in terms of weight penalties rather than looking at some of the real-life advantages that might come with low bulkhead settings and using them to give lower bulkheads an actual pro in regards to max? Finally I'd like to give you my current example of a semi-competitive 1940s era battleship, to really ram home the point. The second picture below is my current build, my current design for a US super-Iowa. maximum bulkheads, long range, maximum displacement (109000t or about two yamatos worth) and 30 knots of speed. This baby costs a whopping 236000000$, or 2.3 regular iowas, has zero rudder or turret rotation upgrades because I couldn't spare the weight, also has only a double bottom and lvl 1 torp protection because that isn't important enough either, meaning that it actually has far worse underwater protection than the Iowa herself (3 torp bulkheads, equivalent to lvl 3 protection in game, and a tripple hull bottom). However I'd rather forego it and just keep them completely out of torp range if it buys me a bit of extra long-range protection with the way the game works right now. extended belt and deck are both literally left at 0", which is actually quite historical, but logically shouldn't work with maximum bulkheads, yet somehow it does. She also sports 14.4" of deck armour, which is completely inadequate given the current game mechanics but it was the best I could do, and it will only protect her from her own armament inside of 20000m, giving her an extremely narrow zone of immunity of just 3000m, between roughly 17000 and 20000m once her 14" belt is accounted for. Notice that the deck is heavier than the belt. It is so on all my ships of above cruiser size. The only part of her armour that is adequate within the current mechanics of the game is her turret top armour, which I was able to bop up to 21.4", giving her immunity from direct turrent hits from her own guns up to 27000m and below, which at least begins to seem sufficient from a designer's point of view, though still not ideal, even if you disregard the fact that historical battleships usually made do with less than 10" of top turret armour. Meanwhile, her turret front could be reduced all the way down to 18", again giving her immunity from her own guns up to around 9500m, which is actually more than necessary and I might consider giving her a 16" or even 14" turret face instead to give her more deck and turret top protection to bring her closer to a historical result in terms of effective IZ. This example should make it blatantly clear why the current design parameters are not very realistic. A ship that is theoretically not only capable of but specifically designed for fighting at 20000-30000m currently requires much heavier deck than belt armour to enable it to fight at it's own designated combat ranges, and this is true across all the nations (I find it especially enfuriating to contemplate that german ships of 130000t disp. still cannot hope to equip enough deck armour to give them reasonable zones of immunity even against 18" guns, much less 20"ers). Thus I sincerely hope that deck armour will be addressed in the next patch, and made much more effective than it currently is, and that some thought be put into making maximum bulkheads have some drawback to incentivize people to avoid them, rather than just making them prohibitively heavy and expensive to equip, which doesn't really balance things but just makes all other aspects of the design process more aggravating. because you absolutely still have to have max bulkheads anyway, until some balance is introduced that is, possibly in relation to the max-min pen-over-pen dynamics I outlined above. Thanks for reading, and keep up the good work devs, still an amazing product you're developing in spite of it's flaws.