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Post by alexbrunius on May 26, 2019 12:25:25 GMT -6
Armor weight for large ships appear to be scaled based on volume, not area. This results in large ships like the Yamato being absolutely impossible to make with historical armor thickness in RTW2. Expected:Armor of same thickness for a ship that displaces twice as much should not weight twice as much, but rather (Cube Root(2))^2 = 1.587 times as much since that is how much larger area it needs to cover. Actual:Armor of same thickness for a ship that displaces twice as much weight about twice as much ( for ships above 20k ton ). See more details, analysis and testing here: nws-online.proboards.com/post/46783/thread
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Post by christian on May 28, 2019 2:39:29 GMT -6
thats quite the reduction in weight of armor damn
nice to know hope this gets fixed soon armor weights a hell of alot (although to compensate for this penetration has been dramatically reduced ??)
also why the hell were there dips of 30-40% at 16000 tons that makes NO SENSE
i dont even know what went on with light cruiser tonnage ship that seems wonky as hell
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Post by pirateradar on May 28, 2019 3:27:06 GMT -6
Thanks for doing the math to figure this out--I don't know if I would have noticed this on my own.
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Post by dizzy on May 28, 2019 6:26:25 GMT -6
Yes, please fix this! We all want to build the Yamato! Thanks Alexbrunius for figuring this out! Much appreciated!
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Post by christian on May 28, 2019 10:09:21 GMT -6
another fact just dawned on me when armor weight is changed (soon hopefully) to be realistic all ship designs will need to be redesigned with new armor values and weight values for said armor which is gonna take alot of time to redesign
although its alot of effort i would VERY much appreciate making the game as realistic as possible
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AiryW
Full Member
Posts: 183
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Post by AiryW on May 28, 2019 10:53:07 GMT -6
Expected:Armor of same thickness for a ship that displaces twice as much should not weight twice as much, but rather (Cube Root(2))^2 = 1.587 times as much since that is how much larger area it needs to cover. I dont think that is a case because the benefits of a larger ship would not be served by a proportional increase. For example the Iowas at 45 kTons, the South Dakotas at 35 kTons and the Yamatos at 70 kTons had nearly identical cross sections. The increase in weight for the Iowas and Yamatos compared to the South Dakotas came mostly if not entirely from elongating the middle area. Thus the increase in belt surface area would be much closer to linear with cubic. These are an extreme case but I would expect a similar trend in general. In general ships grew in size because of the desire for higher speeds and in order to get faster they needed to be longer (for the wave form) and avoid getting fatter (because of displacement resistance). I suppose we might ask that it be made possible to customize the ship hull form a bit more. However the game aims for a reasonable layer of compromise and abstraction so you dont need a degree in naval engineering to play it. Besides such a change would be a very large labor to program. And the Iowa is probably just a straight up more desirable hull form then the Yamato, so they devs assume the player is going for the more advanced concept not the less advanced one. In general I think it's bad for games to have choices with only one good answer. It might be nice if the armor weight could be more closely tied to the horsepower (size of the engine areas) however that would not fit well with the current design system. Perhaps as a middle ground on complexity there could be a ship hull form selection akin to the armor scheme selection? As technology increases more sophisticated hull forms would be unlocked and it would even be possible to rebuild with a more advanced form (increasing displacement by a certain proportion as the ship is elongated). A less advanced hull form would have a speed penalty when going above a certain speed. However the more advanced the hull form the more close to linear the trend in armor costs becomes. This would emulate the historical dynamic at least somewhat and I dont think it's quite as complex as modeling the complete wave form.
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Post by dizzy on May 28, 2019 11:04:02 GMT -6
another fact just dawned on me when armor weight is changed (soon hopefully) to be realistic all ship designs will need to be redesigned with new armor values and weight values for said armor which is gonna take alot of time to redesign although its alot of effort i would VERY much appreciate making the game as realistic as possible Yes! Please! Build the Yamato!
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Post by christian on May 28, 2019 12:41:19 GMT -6
Expected:Armor of same thickness for a ship that displaces twice as much should not weight twice as much, but rather (Cube Root(2))^2 = 1.587 times as much since that is how much larger area it needs to cover. I dont think that is a case because the benefits of a larger ship would not be served by a proportional increase. For example the Iowas at 45 kTons, the South Dakotas at 35 kTons and the Yamatos at 70 kTons had nearly identical cross sections. The increase in weight for the Iowas and Yamatos compared to the South Dakotas came mostly if not entirely from elongating the middle area. Thus the increase in belt surface area would be much closer to linear with cubic. These are an extreme case but I would expect a similar trend in general. In general ships grew in size because of the desire for higher speeds and in order to get faster they needed to be longer (for the wave form) and avoid getting fatter (because of displacement resistance). I suppose we might ask that it be made possible to customize the ship hull form a bit more. However the game aims for a reasonable layer of compromise and abstraction so you dont need a degree in naval engineering to play it. Besides such a change would be a very large labor to program. And the Iowa is probably just a straight up more desirable hull form then the Yamato, so they devs assume the player is going for the more advanced concept not the less advanced one. In general I think it's bad for games to have choices with only one good answer. It might be nice if the armor weight could be more closely tied to the horsepower (size of the engine areas) however that would not fit well with the current design system. Perhaps as a middle ground on complexity there could be a ship hull form selection akin to the armor scheme selection? As technology increases more sophisticated hull forms would be unlocked and it would even be possible to rebuild with a more advanced form (increasing displacement by a certain proportion as the ship is elongated). A less advanced hull form would have a speed penalty when going above a certain speed. However the more advanced the hull form the more close to linear the trend in armor costs becomes. This would emulate the historical dynamic at least somewhat and I dont think it's quite as complex as modeling the complete wave form. also the iowas hull shape is not neccesarily more advanced its just longer for more speed this has been known for a very long time lenght = speed but sometimes you just dont want to go 33 knots and instead want the bigger guns more armor and what other benefits come with being extra thicc the problem is still that armor weights around 30% too much or even more trying to build the yamato the total armor weight ends up being 30% too much and this is a trend we see across all historical recreations do remember if a ship suddenly doubles in tonnage that also means the armor belts grow further from eachother and while yes the belts grow longer they dont double in size this means that the volume of the ship increases dramatically while the armor does not get much more added (except from a couple meters width to the deck and also a couple of meters in belt lenght) if we were to say armor weight doubled on a ship that weighted lets say 40k tons this imaginary 40k ton ship suddenly doubled in armor weight and tonnage this would mean the ship now weights 80k tons BUT the ship is far from twice as big but what it does mean is that the armor belt instead of the previous 100m belt is now 200 meter long the previous 30 meter wide deck is now twice as long while still being as wide if the armor is to weight as much as it does in game so unless this ship just got twice as long and did not grow in width this ship should have armor that weights less but going from 40k to 80k is almost gauranteed to make it wider and the citadelle is almost gauranteed to now grow twice as large thats the root of the problem the game assumes that doubling of ship tonnage means the ship becomes twice as big and in turn the armor tonnage becomes twice as large for example i have a ship thats 40k tons 10 inch belt 27 knots oil fired the total armor weight for the 10 inch belt is 5638 and when i double the TONNAGE i get 11055 tonnage of armor which is barely 200 tons short of being DOUBLE while the ship does not increase by twice in lenght of belt or in any size dimension a double in tonnage should not make the ship armor twice as big
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Post by alexbrunius on May 29, 2019 2:12:20 GMT -6
I dont think that is a case because the benefits of a larger ship would not be served by a proportional increase. For example the Iowas at 45 kTons, the South Dakotas at 35 kTons and the Yamatos at 70 kTons had nearly identical cross sections. The increase in weight for the Iowas and Yamatos compared to the South Dakotas came mostly if not entirely from elongating the middle area. Thus the increase in belt surface area would be much closer to linear with cubic. These are an extreme case but I would expect a similar trend in general. In general ships grew in size because of the desire for higher speeds and in order to get faster they needed to be longer (for the wave form) and avoid getting fatter (because of displacement resistance). This isn't really correct. Comparing South Dakota with Iowa is a bad example because they were restricted by the Panama Canal and had no where else to go but making their ships longer. South Dakota also was unnaturally short since that was the approach the designers choose to save tons on armor weight for the treaty so we need as you say be aware that we are comparing two extreme examples here. But let's put them next to each-other for the sake of argument anyways: Yamato, 260m Length and 38.9m beam ( 68000 tons ) Iowa, 270m Length and 33 meter beam ( 51000 tons ) South Dakota, 207m length and 33 meter beam ( 40000 tons ) Now if we use the South Dakota as baseline the Yamato displaces 1.7 times more, so we expect it to have an area scaling of 1.42 and a length scaling of about 1.19. This means an upscaled South Dak to the tonnage of the Yamato should have a beam of 33x1.19 = 39,3 meters and a length of 247 meters. We don't end up horribly far from Yamatos dimentions here to be perfectly honest with the beam being just 1% off, and length being 5% off. After studying the cross sections and armor layouts further I also concluded that the South Dakotas belt sits about 1m inside the ship compared to it's full width, so it's citadel is actually not 33m wide, only ~31 meter, while the Yamatos Citadel sits on the outside, and when it comes to length the Yamatos citadel is only about 130 meters long while a brief look at the South Dakota tells you that the citadel need to be longer than half the ships length to cover it's 3 turrets. In the end what matters is how much volume is inside the citadel for buoyancy and engines/munitions so again... you cannot cheat physics. Reference Yamato Citadel cross section: live.staticflickr.com/2801/4181515847_57734fe349_b.jpgReference South Dakota Cross section ( It's the one with "C" bottom left ): i.imgur.com/aaKwMdc.pngI do agree with you and others that it would be interesting to be able to play around with the overall ship shape as well, and opt for slower bulkier ships with more effective armor layouts or longer ships that trade armor efficiency for speed, but the current version don't allow us to tweak any of these parameters so we don't really have anything to go by here other than assuming all ships at least of the same class have similar shapes regardless of size for the purposes of calculation. That also would need to factor in number of center-line main gun turrets though, because just like machinery that also is a driver of citadel length.
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Post by L0ckAndL0ad on Jun 2, 2019 3:52:58 GMT -6
Not sure if this thread is bug forum worthy, probably better be in suggestions, but yeah, I agree, I've never been able to replicate historical ships. They are much heavier than IRL. Even when trying to max weight saving tech above everything else. Here's my latest North Carolina replica. I had to sacrifice main battery ammo. IRL they were having like 130-150 rounds per gun IIRC. This ship does have 2 catapults and 3 floatplanes w/ hangar though. They were historically designed in 1935, laid down in 1937, so the year is okay. 45500 (full load historical) vs 52000 actual is just.. yeah.. and without 1/3 of ammo. Feels wrong. Every time, for any ship. Still fun to design! 21-35 KYD immunity zone from 16q1 in guns is sweet. Realistically, with inclined belt, gotta be even better...
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Post by dizzy on Jun 2, 2019 6:44:11 GMT -6
@lockandload yea, they need to fix it.
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Post by williammiller on Jun 2, 2019 14:27:17 GMT -6
Its on The List © :-)
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Post by alexbrunius on Jun 3, 2019 1:33:44 GMT -6
Thanks for the confirmation Williammiller! Totally understandable that this might not be trivial to fix since it impacts alot of other balancing, and that you want to prioritize crashes or other more critical bugs ( This one has been in since RTW1 after all and is just more noticeable now with larger ships being possible ). Do you plan to also fix this issue at the same time? nws-online.proboards.com/thread/2341/larger-displacement-result-lighter-armor
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Post by christian on Jun 3, 2019 6:21:17 GMT -6
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Post by williammiller on Jun 4, 2019 20:23:23 GMT -6
Note: The 1.03 update addresses this weight scaling issue to some degree: "Made armor slightly lighter on very large ships(> 45000 tons)."
Now, I don't personally know the specifics/internals of this change as of typing this so I cannot elaborate on it, but we will be looking at this more so AFAIK this is an interim step in addressing the issue.
Thanks!
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