weight distribution on ships more specificaly battleships

[dorn]

Feb 19, 2019 3:49:19 GMT -6 imryn said:

Feb 18, 2019 14:40:29 GMT -6 archelaos said:

Hardly breaking the laws of physics surely, just extending the available options.

NOT due to armour, whether absurd or not. Ship gets damaged and the AI turns it away - it doesn't make a bit of difference whether it is damaged by a 17" hit on a 6" deck or a 15" hit on a 3" deck. The AI's behavior does not change. The 18+ mod actually adds additional designs for the AI that have realistic levels of deck armour.

ITS NOT LARGER!!!! ITS NOT SMALLER!!! It is the SAME VOLUME. The armour and damage models used in WOWS are pretty realistic, the accuracy of the guns is where it is unrealistic. In WOWS the guns are at least 1000% more accurate that real life, to suit the arcade style of gameplay. Every ship has stuff outside the citadel that is critical and can be destroyed. The Bismark has been criticised for this, but it is true for all ships. Fire control, command and control, communications etc all have to be outside the citadel.

The danger presented by flooding above the citadel exists, however it is caused by the water moving from side to side and causing the ship to capsize. This is what happened to the Kirishima. The Bismark was designed with very heavy compartmentalisation in this area and despite taking vastly more damage than the Kirishima did is not reported to have any stability issues.

In the real world protection against bombs was provided by adding additional armoured decks above the main armoured deck. The purpose was to trigger the fuse in the bomb to cause it to detonate above the main armoured deck, so these additional decks had to be far enough above the main armoured deck to allow for the fuse delay. Thus there is a fixed vertical distance between the two armoured deck. Putting armoured decks this high up in the ship presents all sorts of problems with stability. Because a turtleback armoured deck is positioned much lower in the ship than a flat armoured deck these additional armoured decks can be positioned proportionately lower in the ship and still maintain the necessary vertical separation, and thus cause fewer stability issues.

Please, calm down. There is no reason to be rude. Use arguments and in the case of volume math.

You can take cuboit.

As an example we can take this dimension which are reasonable close to citadel ratio.

Lenght: 120

Width: 30

Height: 7

We can get volume: 120*30*7=25200

We can thing that turtle back citadel will be height only 6 with same width 30. We can get lenght of 140.

No we can calculate are:

Turtle back armor

Belt: 2*140*6+2*30*6 = 2040

Deck: 140*30=4200

Flat deck on top:

Belt: 2*120*7+2*30*7 = 2100

Deck: 120*30 = 3600

We can use some standard armor thicknes used: 14 belt, 5 deck

Turtle back armor: 49560

Flat deck on top: 47400

As you can see turtle back armor is heavier. And I do not take into considaration sloped deck adding additonal armor because of slope for turtle back armor scheme.

But the sloped deck mainly helps in short guns duels because as range increase the angle of shell change making sloped deck less effective. And sloped deck protects mainly low part of citadel as only part of that large citadel is protected by sloped deck. The sloped deck divaded citadel into to parts (see picture several pages back), bellow deck armor and above deck armor. Practically it is not citadel as the higher part up to belt armor from deck armor has no protection against plungin fire. The citadel for turtle back armor is only for flooding purposes as long as as belt armor is not bellow waterline (bad weather problem).

So question is why no navy (except Kriegsmarine) build turtle back armor. I think that it is because of this advantages and disadvantages of turtle back armor:

1. short gun duel - advantage (better protected lower part of citadel) but not buoyancy! as there is space above deck armor calculated to volume of citadel.

2. long gun duel - disadvantage (less protected volume)

3. bomb damage - disadvantage (bombs could explodes deeper into the ship)

4. overal protection of volume - disadvantage as flooding area is same however because of lower deck the more area of ship is not protected

5. armor weight - disadvantage as you need more weight for same flooding protection and less overall protection

To sum it up, for more weight you get better protection of very internal parts of ship but not better protection of buoyancy and much worse protection in long ranges and against bombs.
I can easily see why navies choose flat deck on top.

The one of modern ships with turtle back armor Bismarck has a lot of other flaws, mainly forward and aft bulkeads, less protected main guns, a lot of systems over deck armor so in citadel but not protected by plungin fire.

The others are Scharnhorst class but there were even more flaws even if they were in same areas more armored.

[sykes]

Feb 19, 2019 3:49:19 GMT -6 imryn said:

[...] The armour and damage models used in WOWS are pretty realistic, the accuracy of the guns is where it is unrealistic. In WOWS the guns are at least 1000% more accurate that real life, to suit the arcade style of gameplay.

Except that in World of Warships, the following are
true;

• Shell plating is tiered and can get thick enough to be effective armour due to ricocheting shellfire. Including large calibre gunfire ("Only the Yamato can overmatch 32mm of bow armour", is how I've heard it put).
• AP shellfire cannot cause fire or progressive flooding. Ever.
• Progressive flooding is a status effect that causes HP loss and slows the ship down. There can only be 1 flooding status effect at a time and there are never any issues with trim or list after damage.
• Ships with unitary machinery layouts can lose all propulsion from a single hit to the machinery spaces, unless they pay for the captain perk Last Stand. This means the ship that captain is commanding always gets the benefit of being able to split the machinery, even if they couldn't. (See all 3 boiler Japanese destroyers...)
• Have multiple fires, flooding, weapons disabled, steering gear and/or machinery knocked out, or any combination thereof? Use your damage control party consumable! It'll clear all those nasty status effects instantly, and even give you temporary immunity to new status effects!

And those are only the ones I can think of...

Very realistic armour and damage models, yes.

Totally not undermining your arguments, yes.

[imryn]

Feb 19, 2019 4:14:26 GMT -6 dorn said:

Feb 19, 2019 3:19:14 GMT -6 imryn said:

The AI will turn individual ships away and run them towards its home port, leaving the remainder of its fleet in place fighting you. This will continue until the AI either runs away or closes in to destroy you. Given how conservative the AI is if it thinks it can destroy you then you are really in a bad place. If the AI runs away you will have an opportunity to pursue with your faster BC's, assuming you have them, they are undamaged, and they have ammunition left. You will have a short time where you can actually run down and kill AI's ships before the bulk of his fleet is safe in port.

This is massively inefficient. Most of your ammunition is expended at long range causing damage to ships that will escape and be repaired to fight another day, and the actual number of ships you sink will be a tiny portion of the ships you damage. If you take steps to control the actions of the AI, as I described earlier you will have the opportunity to sink every one of those ships instead of just damaging them.

According to everything I have read there were no capital ships built after 1912 that didn't have a citadel once the concept was introduced (re-introduced, technically) by the USA. All of Nothing design principals were applied to every ship built from that time onwards, regardless of whether they were protected by a flat deck on belt armour scheme or not. RTW is BASED on real history, but that is just the starting point. Within the game we have technologies that existed in the real world and we are allowed to apply them as we see fit. The USA never built a ship with an ABL turret layout (I don't think they did anyway) so should they be prevented from building one in RTW? For that matter should we be limited to only build copies of ships that existed in the real world?

The question of protecting ships from bombs is a complex one, but one method that was used in the real world was to add additional armoured decks above the main armoured deck. The purpose was to trigger the fuse in the bomb to cause it to detonate above the main armoured deck, so these additional decks had to be far enough above the main armoured deck to allow for the fuse delay you described. Thus there is a fixed vertical distance between the two armoured deck. Putting armoured decks this high up in the ship presents all sorts of problems with stability. Because a turtleback armoured deck is positioned much lower in the ship than a flat armoured deck these additional armoured decks can be positioned proportionately lower in the ship and still maintain the necessary vertical separation, and thus cause fewer stability issues.

Yes, it was reintroduced by USN however the first capital ship except USN I am aware using this was Nelson class battleships.

Relating to bombs you can do it and designers did it but than you can increase the dealy. So it is again circle. However effect of armor scheme used except Bismarck was that the damage by boms is as much as high as possible. Which is not possible with turtle back armor without additional deck armor above practically doubling amount of deck armor.

Relating to ABL design. It should be done similar way as 4 centerline turrets or 5 centerline turrets - you need to invented it - it would be this way in RTW2, developers mentioned it.

The stability issue with armor higher could be issue however it was mainly issue of carriers and cruisers after adding a lot of additional AA guns. Look at HMS Vanguard, her deck is quite high and she was very stable gun platform.

You are confusing All or Nothing design principals with flat deck on belt armour. The concept of the armoured citadel was reintroduced by the USN in 1912 as part of the All or Nothing design philosophy, and every capital ship built by every nation from that time on incorporated those principals. Initially only the USN used flat deck on belt, and you are right that Rodney was the first RN ship to use it, however all RN ships built between 1912 and Rodney had armoured citadels even though they did not use a proper AoN armour scheme.

You sum up the problem of protecting ships from bombs. Ultimately there is no way to provide full protection and the bomb always wins, however the strength of the protection you can provide is limited by the vertical distance between the main armoured deck and the highest point in the ship you can put an armoured deck capable of triggering a bomb fuse. A ship with a turtleback armoured deck will always have a greater vertical distance available than a ship with a flat armoured deck due to the deck being positioned lower in the ship. This means that a ship with a turtleback deck can have better protection from bombs than a ship with a flat deck.

I don't disagree that ABL should be an invention unlock, but why is it that you are happy for such ahistorical (i do like that word) options but are so against making a turtleback armoured deck a similar unlock, that can then be used in whatever designs we want? If you feel that way why not limit flat deck on belt to USN only? They were the only ones that used it in the RTW time frame. Why allow 17" and 18" guns for anyone? There are many technologies that are present in RTW that were either limited to single nations or a small subset, but we allow every nation to use them.

Why must the turtleback armoured deck be irrevocably linked to a flawed real world ship and thus tainted forever?

The Bismark was a good first attempt at a battleship. It had design flaws, and much of the armour scheme was designed to fight the last war, and not the next one, but that was true of almost every ship being built at the time. The fact is that the Bismark has been put under a microscope like no other ship in history. Historians have dissected every aspect of the ships design with the perfect vision of 20/20 hindsight and called it a failure, but is that fair? The historians all agree that there was no contemporary ship that could have survived the damage that sunk Bismark, and no contemporary ship that could have put up much more resistance than Bismark did. The "flaws" in the armour, the "critical systems" that were not protected by the citadel that caused the ship to be unable to offer effective resistance amounted to a bunch of cable runs and pipes. These should have been under the turtleback, and could have been - it wasn't like there wasn't room for them, but the designers made a mistake. The sort of mistake that would have been corrected in refit, and certainly eliminated in the next class of ship. The truly critical mistakes in Bismarks design are the ones that allowed it to be caught. The torpedo defense system at the stern was fatally flawed which allowed the steering to be disabled - normally referred to by historians as a failure of the "armour" but in fact nothing of the sort when viewed in RTW terms. The other critical failure was to design it with only 3 propeller shafts and not 4, as was more common practice. With 3 shafts they were unable to steer the ship and maintain enough speed using the engines once the steering was damaged; if they had 4 shafts they would have been able to steer and maintain speed and the ship would have escaped the trap.

I am sure that if they had been given the opportunity to learn from experience and apply those lessons to a new design for a follow on class of battleship (as the designers of RN and USN ships did) the German designers would have eliminated most of the flaws.

I believe that the turtleback armour scheme has a place in RTW2 as an alternative to flat deck on belt armour. I believe it should be implemented in such a way as to accurately reflect the inherent limitations and also the inherent strengths. I believe it would offer us a genuine choice between alternative schemes that each have their own strengths and weaknesses and facilitate differing play styles.

[archelaos]

Feb 19, 2019 3:49:19 GMT -6 imryn said:

c. 65,000 tons, 29 kts, 9 x 17" ABL, 24 x 6", 60 x 5", 28" B, 8" D, 28" CT, 29" T, 10" TT, 2" Sec

Hardly breaking the laws of physics surely, just extending the available options.

IMHO this design breaks the laws of physics. It is close in size to Yamato, but it has DOUBLE belt thickness, same deck, much thicker turrets and CT, 2 knots faster, double amount of secondary guns and a whopping FIVE times as much tertiary guns. All this at the cost of an inch smaller main guns. I have hard time to believe there is even enough space on c 65k ton ship to fit all that guns not to mention ammo and crew. Such massive increase in armour would in fact make the ship smaller (you have to somehow save good 10-15k of hull construction steel as that's the weight of all that additional (over Yamato) armour you have. So the ship would have to be smaller (shorter, narrower etc) than Yamato

NOT due to armour, whether absurd or not. Ship gets damaged and the AI turns it away - it doesn't make a bit of difference whether it is damaged by a 17" hit on a 6" deck or a 15" hit on a 3" deck. The AI's behavior does not change. The 18+ mod actually adds additional designs for the AI that have realistic levels of deck armour.

ITS NOT LARGER!!!! ITS NOT SMALLER!!! It is the SAME VOLUME. The armour and damage models used in WOWS are pretty realistic, the accuracy of the guns is where it is unrealistic. In WOWS the guns are at least 1000% more accurate that real life, to suit the arcade style of gameplay. Every ship has stuff outside the citadel that is critical and can be destroyed. The Bismark has been criticised for this, but it is true for all ships. Fire control, command and control, communications etc all have to be outside the citadel.

How it is the same volume if it is 2 decks or so lower? You have 150x20x16 box and 150x20x12 box how on earth can they have the same volume? You will lose around 20% of volume by going 2 decks (4m) lower and will have to make citadel longer and/or wider to get it back. Even if we assume the armour weight between AoN and turtle deck balances out (I don't think so) your ship will have heavier armour due to having longer belt and/or wider deck so you will have less free displacement to use on other things.

And only thing realistic in WoWS are some of the ship models. Accuracy is part of the problem, as it do not scale properly with distance - too accurate at long, awfully inaccurate up close.
The same guns having wildly different characteristic on different ships, especially BB secondaries having abysmal performance compared to same guns used as primaries on cruisers or everything moving faster than in reality, except turret traverse would be IMHO the biggest offenders.
And if damage model was realistic, it would promote fighting in realistic manner, instead, it promotes fighting bow on which was always considered disadvantageous position in reality. As it is now, pens to the citadel give massive damage while pens everywhere else produce just a little damage. It would be ok if we assume that only citadel is filled with critical systems and that "density" of those systems is the same in every ship. Which obviously is wrong, as AoN ships do not have more critical spaces than turtledeck ship of same tech. AoN and turtledeck ships have roughly same systems in hull, only in AoN ships 20% of those is protected by armour while on turtledeck it is not. As result some citadel penetrations in a AoN ship would not generate critical damage in real life, while some of the non-citadel hits on turtledeck ships would cause critical damage. Which is completely opposite to WoWS system.


The danger presented by flooding above the citadel exists, however it is caused by the water moving from side to side and causing the ship to capsize. This is what happened to the Kirishima. The Bismark was designed with very heavy compartmentalisation in this area and despite taking vastly more damage than the Kirishima did is not reported to have any stability issues.

In the real world protection against bombs was provided by adding additional armoured decks above the main armoured deck. The purpose was to trigger the fuse in the bomb to cause it to detonate above the main armoured deck, so these additional decks had to be far enough above the main armoured deck to allow for the fuse delay. Thus there is a fixed vertical distance between the two armoured deck. Putting armoured decks this high up in the ship presents all sorts of problems with stability. Because a turtleback armoured deck is positioned much lower in the ship than a flat armoured deck these additional armoured decks can be positioned proportionately lower in the ship and still maintain the necessary vertical separation, and thus cause fewer stability issues.

I will restate what I said earlier - if your fusing deck is at roughly same level as AoN main deck, massively larger volume of the ship (good 20%) is completely unprotected against bomb damage. Again, this is NOT AN EMPTY SPACE.

The Bismark was a good first attempt at a battleship.

No, it was not. Scharnhorst-class BB/BCs were first attempt.

dorn

I think you underestimate volume loss - a single deck would be closer to 2m than 1m in height and turtledeck would be 2 decks lower (based on Bismarck)

[imryn]

Feb 19, 2019 5:07:07 GMT -6 dorn said:

Feb 19, 2019 3:49:19 GMT -6 imryn said:

Hardly breaking the laws of physics surely, just extending the available options.

NOT due to armour, whether absurd or not. Ship gets damaged and the AI turns it away - it doesn't make a bit of difference whether it is damaged by a 17" hit on a 6" deck or a 15" hit on a 3" deck. The AI's behavior does not change. The 18+ mod actually adds additional designs for the AI that have realistic levels of deck armour.

ITS NOT LARGER!!!! ITS NOT SMALLER!!! It is the SAME VOLUME. The armour and damage models used in WOWS are pretty realistic, the accuracy of the guns is where it is unrealistic. In WOWS the guns are at least 1000% more accurate that real life, to suit the arcade style of gameplay. Every ship has stuff outside the citadel that is critical and can be destroyed. The Bismark has been criticised for this, but it is true for all ships. Fire control, command and control, communications etc all have to be outside the citadel.

The danger presented by flooding above the citadel exists, however it is caused by the water moving from side to side and causing the ship to capsize. This is what happened to the Kirishima. The Bismark was designed with very heavy compartmentalisation in this area and despite taking vastly more damage than the Kirishima did is not reported to have any stability issues.

In the real world protection against bombs was provided by adding additional armoured decks above the main armoured deck. The purpose was to trigger the fuse in the bomb to cause it to detonate above the main armoured deck, so these additional decks had to be far enough above the main armoured deck to allow for the fuse delay. Thus there is a fixed vertical distance between the two armoured deck. Putting armoured decks this high up in the ship presents all sorts of problems with stability. Because a turtleback armoured deck is positioned much lower in the ship than a flat armoured deck these additional armoured decks can be positioned proportionately lower in the ship and still maintain the necessary vertical separation, and thus cause fewer stability issues.

Please, calm down. There is no reason to be rude. Use arguments and in the case of volume math.

You can take cuboit.

As an example we can take this dimension which are reasonable close to citadel ratio.

Lenght: 120

Width: 30

Height: 7

We can get volume: 120*30*7=25200

We can thing that turtle back citadel will be height only 6 with same width 30. We can get lenght of 140.

No we can calculate are:

Turtle back armor

Belt: 2*140*6+2*30*6 = 2040

Deck: 140*30=4200

Flat deck on top:

Belt: 2*120*7+2*30*7 = 2100

Deck: 120*30 = 3600

We can use some standard armor thicknes used: 14 belt, 5 deck

Turtle back armor: 49560

Flat deck on top: 47400

As you can see turtle back armor is heavier. And I do not take into considaration sloped deck adding additonal armor because of slope for turtle back armor scheme.

But the sloped deck mainly helps in short guns duels because as range increase the angle of shell change making sloped deck less effective. And sloped deck protects mainly low part of citadel as only part of that large citadel is protected by sloped deck. The sloped deck divaded citadel into to parts (see picture several pages back), bellow deck armor and above deck armor. Practically it is not citadel as the higher part up to belt armor from deck armor has no protection against plungin fire. The citadel for turtle back armor is only for flooding purposes as long as as belt armor is not bellow waterline (bad weather problem).

So question is why no navy (except Kriegsmarine) build turtle back armor. I think that it is because of this advantages and disadvantages of turtle back armor:

1. short gun duel - advantage (better protected lower part of citadel) but not buoyancy! as there is space above deck armor calculated to volume of citadel.

2. long gun duel - disadvantage (less protected volume)

3. bomb damage - disadvantage (bombs could explodes deeper into the ship)

4. overal protection of volume - disadvantage as flooding area is same however because of lower deck the more area of ship is not protected

5. armor weight - disadvantage as you need more weight for same flooding protection and less overall protection

To sum it up, for more weight you get better protection of very internal parts of ship but not better protection of buoyancy and much worse protection in long ranges and against bombs.
I can easily see why navies choose flat deck on top.

The one of modern ships with turtle back armor Bismarck has a lot of other flaws, mainly forward and aft bulkeads, less protected main guns, a lot of systems over deck armor so in citadel but not protected by plungin fire.

The others are Scharnhorst class but there were even more flaws even if they were in same areas more armored.

I am calm, and I am happy with your maths, I have always said that it would be heavier than flat deck scheme, along with a bunch of other limitations as well.

You lost me when you started talking about divided citadels. The area above the turtleback deck is not the citadel, the citadel (that should contain all the critical systems) is the area below the turtleback and the citadel has enough reserve buoyancy to keep the ship afloat. The stability issues with flooding above the citadel were apparently mitigated by compartmentalisation. Protection of the citadel from plunging fire is provided by the deck armour just like any other ship.

1. equal in buoyancy - space above turtleback is not part of citadel and not needed to preserve reserve buoyancy of citadel.
2. No. SAME protected volume.
3. No. Armoured decks to detonate bombs are easier to mount on turtleback ships and as long as the bomb detonates outside the citadel effect is equal.
4. Overall protection of volume is diametrically opposed to AoN principals so I am not sure what you mean.
5. More weight but not less protection

For more weight i get better protection of the citadel, exactly the same buoyancy, the same protection against bombs (but with fewer stability issues), and the same protection against long range fire.

All of the flaws in Bismark can be ascribed to an inexperienced design team. The systems that were over the turtleback were not in the citadel - they should have been, I agree, and could have been, and probably would have been in a follow in class. The same with the weakness of the barbettes and turret facings and the lack of angling in the turret facings... the list goes on and on. But I still maintain that these were issues that could have been resolved in follow on ships.

[imryn]

Feb 19, 2019 5:56:45 GMT -6 archelaos said:

Feb 19, 2019 3:49:19 GMT -6 imryn said:

c. 65,000 tons, 29 kts, 9 x 17" ABL, 24 x 6", 60 x 5", 28" B, 8" D, 28" CT, 29" T, 10" TT, 2" Sec

Hardly breaking the laws of physics surely, just extending the available options.

IMHO this design breaks the laws of physics. It is close in size to Yamato, but it has DOUBLE belt thickness, same deck, much thicker turrets and CT, 2 knots faster, double amount of secondary guns and a whopping FIVE times as much tertiary guns. All this at the cost of an inch smaller main guns. I have hard time to believe there is even enough space on c 65k ton ship to fit all that guns not to mention ammo and crew. Such massive increase in armour would in fact make the ship smaller (you have to somehow save good 10-15k of hull construction steel as that's the weight of all that additional (over Yamato) armour you have. So the ship would have to be smaller (shorter, narrower etc) than Yamato

NOT due to armour, whether absurd or not. Ship gets damaged and the AI turns it away - it doesn't make a bit of difference whether it is damaged by a 17" hit on a 6" deck or a 15" hit on a 3" deck. The AI's behavior does not change. The 18+ mod actually adds additional designs for the AI that have realistic levels of deck armour.

ITS NOT LARGER!!!! ITS NOT SMALLER!!! It is the SAME VOLUME. The armour and damage models used in WOWS are pretty realistic, the accuracy of the guns is where it is unrealistic. In WOWS the guns are at least 1000% more accurate that real life, to suit the arcade style of gameplay. Every ship has stuff outside the citadel that is critical and can be destroyed. The Bismark has been criticised for this, but it is true for all ships. Fire control, command and control, communications etc all have to be outside the citadel.

How it is the same volume if it is 2 decks or so lower? You have 150x20x16 box and 150x20x12 box how on earth can they have the same volume? You will lose around 20% of volume by going 2 decks (4m) lower and will have to make citadel longer and/or wider to get it back. Even if we assume the armour weight between AoN and turtle deck balances out (I don't think so) your ship will have heavier armour due to having longer belt and/or wider deck so you will have less free displacement to use on other things.

And only thing realistic in WoWS are some of the ship models. Accuracy is part of the problem, as it do not scale properly with distance - too accurate at long, awfully inaccurate up close.
The same guns having wildly different characteristic on different ships, especially BB secondaries having abysmal performance compared to same guns used as primaries on cruisers or everything moving faster than in reality, except turret traverse would be IMHO the biggest offenders.
And if damage model was realistic, it would promote fighting in realistic manner, instead, it promotes fighting bow on which was always considered disadvantageous position in reality. As it is now, pens to the citadel give massive damage while pens everywhere else produce just a little damage. It would be ok if we assume that only citadel is filled with critical systems and that "density" of those systems is the same in every ship. Which obviously is wrong, as AoN ships do not have more critical spaces than turtledeck ship of same tech. AoN and turtledeck ships have roughly same systems in hull, only in AoN ships 20% of those is protected by armour while on turtledeck it is not. As result some citadel penetrations in a AoN ship would not generate critical damage in real life, while some of the non-citadel hits on turtledeck ships would cause critical damage. Which is completely opposite to WoWS system.


The danger presented by flooding above the citadel exists, however it is caused by the water moving from side to side and causing the ship to capsize. This is what happened to the Kirishima. The Bismark was designed with very heavy compartmentalisation in this area and despite taking vastly more damage than the Kirishima did is not reported to have any stability issues.

In the real world protection against bombs was provided by adding additional armoured decks above the main armoured deck. The purpose was to trigger the fuse in the bomb to cause it to detonate above the main armoured deck, so these additional decks had to be far enough above the main armoured deck to allow for the fuse delay. Thus there is a fixed vertical distance between the two armoured deck. Putting armoured decks this high up in the ship presents all sorts of problems with stability. Because a turtleback armoured deck is positioned much lower in the ship than a flat armoured deck these additional armoured decks can be positioned proportionately lower in the ship and still maintain the necessary vertical separation, and thus cause fewer stability issues.

I will restate what I said earlier - if your fusing deck is at roughly same level as AoN main deck, massively larger volume of the ship (good 20%) is completely unprotected against bomb damage. Again, this is NOT AN EMPTY SPACE.

The Bismark was a good first attempt at a battleship.

No, it was not. Scharnhorst-class BB/BCs were first attempt.

dorn

I think you underestimate volume loss - a single deck would be closer to 2m than 1m in height and turtledeck would be 2 decks lower (based on Bismarck)

The values for armour thickness in ship designs are not actual thicknesses of armour, the system is abstracted based on the amount of protection offered by a 1" armour plate built in 1900. I know, it confused me at first, but this is so that the game can scale through all of the armour upgrades without breaking down, and we get a number that means the same thing in 1900 as it does in 1925. 28" armour belt in 1925 probably represents an actual plate of half that thickness or even less. As for the rest of your complaints about my design -  I would point out that I designed it in a computer game not in the real world. Different constraints, different limits, not reality.

We have been over and over the volume question. The citadel has to be the same volume to incorporate the necessary reserve buoyancy, so if we make it shorter we have to make it either longer or wider. The weight doesn't balance out - turtleback deck weighs the same as sloped deck of same thickness, and there are no benefits for ABL turrets etc.

I take your point about WOWS, there is a lot that isn't accurate (Ha!) in that game, but I think the detailed armour models are pretty good. One of the things they have right is the way a Flat deck on belt (not AoN ship please) is vulnerable to having its citadel penetrated through the belt. The citadel contains most of a ships critical systems, regardless of the armour scheme applied, and any shell that penetrates the citadel causes enormous (often catastrophic) damage. A ship with a turtleback armoured deck was effectively immune to that type of hit through the belt. If anything, WOWS has toned down the effectiveness of a turtleback armoured deck at short range to maintain game balance.

The parts of a ship that are outside the citadel are not empty but they don't contain anything that is deemed critical to the ability of the ship to fight. The fact that the turtleback deck sits so much lower in the hull actually means that I can mount the armoured deck that triggers the bomb fuse higher in the ship than a ship with a flat deck could, meaning the bomb would detonate higher in the ship with a turtleback than on a ship with flat deck.

[dorn]

archelaos

I now that it is more height. I just want to show how even decrease by 1 needs increase by 20 lenght. And in real ship forward and aft section has less volume but the area of belt does not increase in same ratio. This is another reason why short citadel is much more effective.

imryn

You are wrong that standard armor was not used after Nevada class in the world. On opposite only USN used AoN armor scheme and the first launched capital ship with AoN armor scheme out of USN was Nelson and Rodney one decade later.

All other capital ships except USN used standard WW1 armor scheme, sloped deck and incremental armor.

I am not developer, developers design the game and the design as I understand is to allow to build ships which are close to history not because they were build but because the thinking envolved that way. And it has additional effect that enhance game that the player cannot build ships much better earlier becuase we know what works and what does not. At that time nobody knows if torpedo will be succesfull, if all main armament (Dreadnought) would be succesfull, if AoN armor scheme would be succesfull etc.
There is possibility in game to use varied technology to substitute this a little however this has some simplified mechanics.

I do not know where you take this but if all the ship is destroyed and your citadel is still without penetration I think that this ship is winner. But in reality it does not work this way. In reality it was Bismarck, just a lot of steel on water without ability to do anything.

I would recommend you read this article.

This is written by Nathan Okun, and it is quite good. It is need to be read carefully, there is a lot of information, a lot of details that needs to be put into whole picture.

German designers could eliminate a lot of flaws in next design as would do other foreign designers (they did not do it as only USN build several classes of battleship and HMS Vanguard was commisioned after the war and was still emergency war program) in their designs however there are several factors which is need to be considered:

1. the most inefficient weight was in Bismarck armor scheme

2. there is still a lot of important parts of ship that could not be protected enough - fire control systems, screws, shafts

[imryn]

Feb 19, 2019 5:36:57 GMT -6 sykes said:

Feb 19, 2019 3:49:19 GMT -6 imryn said:

[...] The armour and damage models used in WOWS are pretty realistic, the accuracy of the guns is where it is unrealistic. In WOWS the guns are at least 1000% more accurate that real life, to suit the arcade style of gameplay.

Except that in World of Warships, the following are
true;

• Shell plating is tiered and can get thick enough to be effective armour due to ricocheting shellfire. Including large calibre gunfire ("Only the Yamato can overmatch 32mm of bow armour", is how I've heard it put).
• AP shellfire cannot cause fire or progressive flooding. Ever.
• Progressive flooding is a status effect that causes HP loss and slows the ship down. There can only be 1 flooding status effect at a time and there are never any issues with trim or list after damage.
• Ships with unitary machinery layouts can lose all propulsion from a single hit to the machinery spaces, unless they pay for the captain perk Last Stand. This means the ship that captain is commanding always gets the benefit of being able to split the machinery, even if they couldn't. (See all 3 boiler Japanese destroyers...)
• Have multiple fires, flooding, weapons disabled, steering gear and/or machinery knocked out, or any combination thereof? Use your damage control party consumable! It'll clear all those nasty status effects instantly, and even give you temporary immunity to new status effects!

And those are only the ones I can think of...

Very realistic armour and damage models, yes.

Totally not undermining your arguments, yes.

LOL Ok you got me. I should have said I like the armour models and the way they interact with incoming fire. The damage implementation and control is pretty cartoony. The overmatch mechanics they use are actually a real thing and do happen in the real world; just nowhere near as often as in WOWS. That's just a knock on effect of having the guns so much more accurate than reality.

[imryn]

Feb 19, 2019 6:49:09 GMT -6 dorn said:

archelaos

I now that it is more height. I just want to show how even decrease by 1 needs increase by 20 lenght. And in real ship forward and aft section has less volume but the area of belt does not increase in same ratio. This is another reason why short citadel is much more effective.

imryn

You are wrong that standard armor was not used after Nevada class in the world. On opposite only USN used AoN armor scheme and the first launched capital ship with AoN armor scheme out of USN was Nelson and Rodney one decade later.

All other capital ships except USN used standard WW1 armor scheme, sloped deck and incremental armor.

I am not developer, developers design the game and the design as I understand is to allow to build ships which are close to history not because they were build but because the thinking envolved that way. And it has additional effect that enhance game that the player cannot build ships much better earlier becuase we know what works and what does not. At that time nobody knows if torpedo will be succesfull, if all main armament (Dreadnought) would be succesfull, if AoN armor scheme would be succesfull etc.
There is possibility in game to use varied technology to substitute this a little however this has some simplified mechanics.

I do not know where you take this but if all the ship is destroyed and your citadel is still without penetration I think that this ship is winner. But in reality it does not work this way. In reality it was Bismarck, just a lot of steel on water without ability to do anything.

I would recommend you read this article.

This is written by Nathan Okun, and it is quite good. It is need to be read carefully, there is a lot of information, a lot of details that needs to be put into whole picture.

German designers could eliminate a lot of flaws in next design as would do other foreign designers (they did not do it as only USN build several classes of battleship and HMS Vanguard was commisioned after the war and was still emergency war program) in their designs however there are several factors which is need to be considered:

1. the most inefficient weight was in Bismarck armor scheme

2. there is still a lot of important parts of ship that could not be protected enough - fire control systems, screws, shafts

I think you are again mixing up All or Nothing design principals and Flat deck on Belt armour. The first is the way the ship is designed, the second is a suitable way to armour the ship, but not the only way.

I was quoting from that article earlier - it is very good. I agree with both you and Nathan Okun that in the real world the turtleback armour scheme was a poor choice compared to the flat deck on belt scheme. I agree that in the real world the protection it offers is very situational and at a cost of a lot of additional weight.

The thing is that RTW and RTW2 are not the real world. The situation under which the turtleback armour scheme offers maximum protection is quite common, and therefore the weight cost might just be worth it.

[dorn]

imryn

I will comment directly in text using different color. This is my last answer as I cannot explained it to you more and if you would like to have your opinion which is opposite the designers that constructed battleships and even experts I will let you.

I am calm, and I am happy with your maths, I have always said that it would be heavier than flat deck scheme, along with a bunch of other limitations as well. Much heavier so inefficient (look at source I gave you).

You lost me when you started talking about divided citadels. The area above the turtleback deck is not the citadel, the citadel (that should contain all the critical systems) is the area below the turtleback and the citadel has enough reserve buoyancy to keep the ship afloat. The stability issues with flooding above the citadel were apparently mitigated by compartmentalisation. Protection of the citadel from plunging fire is provided by the deck armour just like any other ship. In this case you need to take out all part above deck and it is quite a lot of space you cannot easily substitute by lenght.

1. equal in buoyancy - space above turtleback is not part of citadel and not needed to preserve reserve buoyancy of citadel. As mentioned above than for that armor you get much lower space protected by citadel. And part of the ship above deck armor is bellow waterline.
2. No. SAME protected volume. In case you increase lenght of citadel, than yes. But the ship has still a lot of important stuff unprotected.
3. No. Armoured decks to detonate bombs are easier to mount on turtleback ships and as long as the bomb detonates outside the citadel effect is equal. It is the same if the thickness is the same however bombs detonate in turtle back armor close to waterline so it is more likely that even water could get in.
4. Overall protection of volume is diametrically opposed to AoN principals so I am not sure what you mean. The most important is centre of the ship as there is more important equipments so decrease protected volume in adminship and increase it on ends of ship is worse.
5. More weight but not less protection - but it could be much much heavier, protection of Bismarck was in same level as other 35.000 tons battleship, probably even lower, but with 6.000 tons more.

For more weight i get better protection of the citadel, exactly the same buoyancy, the same protection against bombs (but with fewer stability issues), and the same protection against long range fire.

All of the flaws in Bismark can be ascribed to an inexperienced design team. The systems that were over the turtleback were not in the citadel - they should have been, I agree, and could have been, and probably would have been in a follow in class. The same with the weakness of the barbettes and turret facings and the lack of angling in the turret facings... the list goes on and on. But I still maintain that these were issues that could have been resolved in follow on ships.

I am not expert on designing battleship however I do not think that they can be included in citadel with this armor scheme. You need them in center of the ship not in bow or aft.

You can certainly design much large ship with turtle back armor which would have overall similar protection with difference weaknesses however she would be not overall better for tonnage you spent. Because in that case you can build more ship with same budget with overall similar protection.

[dorn]

imryn

Finally we understand each other. 

I think you are again mixing up All or Nothing design principals and Flat deck on Belt armour. The first is the way the ship is designed, the second is a suitable way to armour the ship, but not the only way. I understand what you mean, that you look at it as :

1. if ship has citadel to protect buoyancy

2. how ship is protected - sloped deck vs. flat deck on top of belt armor

I was quoting from that article earlier - it is very good. I agree with both you and Nathan Okun that in the real world the turtleback armour scheme was a poor choice compared to the flat deck on belt scheme. I agree that in the real world the protection it offers is very situational and at a cost of a lot of additional weight. Agreed.

The thing is that RTW and RTW2 are not the real world. The situation under which the turtleback armour scheme offers maximum protection is quite common, and therefore the weight cost might just be worth it.

In case you are speaking of 18+ mod, I cannot tell, I do not use it.

If you speak about standard game, there is no possibility to build ship with citadel to protect enough buoyancy and sloped deck armor except one possibility. The game does not allow it and no ship with such configuration was build at era of the game.

You can build ship which has complex protection from bow to aft if you put BE and DE at same level as B and D. However you get ship too heavy, for vanilla game it is useless as completly inefficient and it is correct.

[elouda]

Firstly - that 'c. 65,000 tons, 29 kts, 9 x 17" ABL, 24 x 6", 60 x 5", 28" B, 8" D, 28" CT, 29" T, 10" TT, 2" Sec' design is utter fantasy. It is literally breaking the laws of physics. The games calculations don't scale right past 52000tons, and you're trying to cram a lot more ship than Yamato onto the same displacement.

Secondly, to adress the volume thing;

Even with a single deck height difference, the volume difference is significant. It worth remembering that the 'wedges' left above the sloped deck are also not part of the protected volume, and these need to be subtracted. There's also a balance with regards to slope angle here - steeper slopes will leave less volume unprotected but come with other downsides. And of course, as the deck doesnt come level with the top of the belt, we need to be a little more creative with our math.

Here's a rough estimate I came up with something in the size range of Bismarck and Vanguard. I am assuming a 'cuboid' ship (block coefficient = 1), but the comparison should hold up even if one wanted to do something more elaborate to account for hullform, as the main belt area of the ship is going to be more blocky than the ends anyway.

I'm going to use an arbitrary weight unit of 'ub' and 'ud' for weight area, for belt and deck respectively. Im assuming belt end bulkheads are the same thickness as the belt itself, so will use the same ub units.

Ship A - Deck on Belt
Belt length of 160m
Belt height of 7m (2m below waterline, 5m above)
Draught of 10m
Beam of 33m

Volume below waterline (under belt area) = 10x33x160 = 52800m3
Volume above waterline (inside belt/deck box) = 5x33x160 = 26400m3
Total enclosed volume = 79200m3

Weight of belt sides = 160x7 = 1120ub (x2 for both sides)
Weight of belt ends = 33x7 = 231ub (x2 for both ends)
Total weight of belt+ends = 2702ub

Weight of deck = 160x33 = 5280ud

If we assume deck to be 1/3 the thickness of belt, we can estimate the armour weight area as 4462ub


Ship B - Turtleback Deck
Belt length of 160m
Belt height of 5m (1.5m below waterline, 3.5m above)
Deck at 1m above waterline
Deck sloped at 30 degrees (= 4.33m 'slope depth' per side, 5m slope length)
Draught of 10m
Beam of 33m

Volume below waterline (under belt area) = 10x33x160 = 52800m3
Volume above waterline (inside turtleback, ignoring 'wedges') = 1x33x160 = 5280m3
Volume not protected due to wedges = 2.5x4.33x160x0.5 = 866m3 (x2 for both sides)
Total enclosed volume = 56348m3

Weight of belt sides = 160x5 = 800ub (x2 for both sides)
Weight of belt ends = 33x5 = 165ub (x2 for both ends)
Total weight of belt + ends = 1930ub

Weight of deck (non-sloped portion) = 160x24.34 = 3894.4ud
Weight of deck slopes = 160x5 = 800ud (x2 for both sides)
Total weight of deck = 5494.4ud

Making the same assumption as above (deck 1/3 thickness of belt), armour weight area estimate of 3761ub

So if we keep the dimensions of the 'box' the same, we get ~71% of the protected volume for ~84% of the weight by using a turtleback over a deck on belt setup.

If we want to get the same protected volume, then lets consider a third ship;

Ship C - Turtleback Deck, Equalized volume
Belt length of 195m
Belt height of 5m (1.5m below waterline, 3.5m above)
Deck at 1m above waterline
Deck sloped at 30 degrees (= 4.33m 'slope depth' per side, 5m slope length)
Draught of 10m
Beam of 36m

Volume below waterline (under belt area) = 10x36x195 = 70200m3
Volume above waterline (inside turtleback, ignoring 'wedges') = 1x36x195 = 7020m3
Volume not protected due to wedges = 2.5x4.33x195x0.5 = 1055.4m3 (x2 for both sides)
Total enclosed volume = 75109.2m3

Weight of belt sides = 195x5 = 975ub (x2 for both sides)
Weight of belt ends = 36x5 = 180ub (x2 for both ends)
Total weight of belt + ends = 2310ub

Weight of deck (non-sloped portion) = 195x27.34 = 5331.3ud
Weight of deck slopes = 195x5 = 975ud (x2 for both sides)
Total weight of deck = 7281.3ud

Making the same assumption as above (deck 1/3 thickness of belt), armour weight area estimate of 4737.1ub

This is ~95% of the protected volume for ~107% of the weight area.

Note that for C I had to also widen the ship, as getting to a similar volume with only length would have required 215m, which if we assume a main belt coverage of 70-75% (Bismarck is ~71%) means a ship length of 286-307m, which is going to add a lot of non armour weight (for reference the A/B ships are 213-228m long at that ratio). Even with the current compromise, the 'underwater' section of C displaces ~35% more than A or B. A more 'square' arrangement allowed by a wider beam would probably also be more weight efficient on the deck on belt A design.

We can also play with that armour thickness ratio I assume as to see how it affects both;

A = 2702ub, 5280ud

C = 2310ub, 7281.3ud

If we assume Deck:Belt thickness ratio of 1:2 instead of 1:3, we get weight area estimates of;

A = 5342ub

C = 5950ub

A/C = +11.5% (vs +7% at 1:3)

At a ratio fo 1:4, we get;

A = 4022ub

C = 4130ub

A/C = +2.5%

So its clear that at equivalent volumes, the weight on the turtleback version is driven more heavily by deck thickness (due to the longer and wider area), which is probably these sorts of designs often had thinner decks in reality. Even at a 'conservative' 1:3 ratio (eg. 110mm deck with a 330mm belt), there is a notable cost in weight.

Conclusion

You're not going to get the same amount of protected volume on a similarly sized ship with a turtledeck design, unless you make one of the compromises I mentioned in the my first post here, which come with their own issues. You -can- get a smaller, better protected volume for the same weight, but that has its own issues.

[imryn]

Feb 19, 2019 7:08:37 GMT -6 dorn said:

imryn

I will comment directly in text using different color. This is my last answer as I cannot explained it to you more and if you would like to have your opinion which is opposite the designers that constructed battleships and even experts I will let you.

I am calm, and I am happy with your maths, I have always said that it would be heavier than flat deck scheme, along with a bunch of other limitations as well. Much heavier so inefficient (look at source I gave you). Heavier yes. Efficiency is assessed based on context. In the real world yes it was inefficient. In RTW I believe it would be efficient.

You lost me when you started talking about divided citadels. The area above the turtleback deck is not the citadel, the citadel (that should contain all the critical systems) is the area below the turtleback and the citadel has enough reserve buoyancy to keep the ship afloat. The stability issues with flooding above the citadel were apparently mitigated by compartmentalisation. Protection of the citadel from plunging fire is provided by the deck armour just like any other ship. In this case you need to take out all part above deck and it is quite a lot of space you cannot easily substitute by lenght. Agreed

1. equal in buoyancy - space above turtleback is not part of citadel and not needed to preserve reserve buoyancy of citadel. As mentioned above than for that armor you get much lower space protected by citadel. And part of the ship above deck armor is bellow waterline. Agreed, the citadel sit lower in the ship but the buoyancy is the same
2. No. SAME protected volume. In case you increase lenght of citadel, than yes. But the ship has still a lot of important stuff unprotected. Agreed, but no more than a flat deck ship
3. No. Armoured decks to detonate bombs are easier to mount on turtleback ships and as long as the bomb detonates outside the citadel effect is equal. It is the same if the thickness is the same however bombs detonate in turtle back armor close to waterline so it is more likely that even water could get in. The bombs detonate a short time after penetrating the armoured deck above the turtleback. the time is determined by the bomb fuse. The higher up in the ship you initiate the fuse the higher up in the ship the bomb will detonate. because turtleback deck is so low we can put the armoured deck for bomb initiation higher up in the ship than an flat deck ship can.
4. Overall protection of volume is diametrically opposed to AoN principals so I am not sure what you mean. The most important is centre of the ship as there is more important equipments so decrease protected volume in adminship and increase it on ends of ship is worse. Agreed but can be applied equally to turtleback and flat deck
5. More weight but not less protection - but it could be much much heavier, protection of Bismarck was in same level as other 35.000 tons battleship, probably even lower, but with 6.000 tons more. Agreed

For more weight i get better protection of the citadel, exactly the same buoyancy, the same protection against bombs (but with fewer stability issues), and the same protection against long range fire.

All of the flaws in Bismark can be ascribed to an inexperienced design team. The systems that were over the turtleback were not in the citadel - they should have been, I agree, and could have been, and probably would have been in a follow in class. The same with the weakness of the barbettes and turret facings and the lack of angling in the turret facings... the list goes on and on. But I still maintain that these were issues that could have been resolved in follow on ships.

I am not expert on designing battleship however I do not think that they can be included in citadel with this armor scheme. You need them in center of the ship not in bow or aft.

You can certainly design much large ship with turtle back armor which would have overall similar protection with difference weaknesses however she would be not overall better for tonnage you spent. Because in that case you can build more ship with same budget with overall similar protection.

"Better" is a very subjective word. I think that the ship I am describing could be built in RTW with a relatively realistic representation of the turtleback armour scheme that was designed using All or Nothing principals. I think it would definitely be heavier than a similar ship with flat deck armour. I think it would have a long citadel (ABXY turret layout). I think it would be significantly better protected a ranges below 12,000 yards. Whether that ship is "better" than a flat deck ship would depend how you play the game.

[imryn]

Feb 19, 2019 7:30:37 GMT -6 elouda said:

Firstly - that 'c. 65,000 tons, 29 kts, 9 x 17" ABL, 24 x 6", 60 x 5", 28" B, 8" D, 28" CT, 29" T, 10" TT, 2" Sec' design is utter fantasy. It is literally breaking the laws of physics. The games calculations don't scale right past 52000tons, and you're trying to cram a lot more ship than Yamato onto the same displacement.

Secondly, to adress the volume thing;

...

Conclusion

You're not going to get the same amount of protected volume on a similarly sized ship with a turtledeck design, unless you make one of the compromises I mentioned in the my first post here, which come with their own issues. You -can- get a smaller, better protected volume for the same weight, but that has its own issues.

I suggest you install the mod and take a look. There is a sticky patch after 51,500 where the calculations for machinery break down but if you move up to 60,000 they work again. If you don't believe my design install the mod and check it out.

Thanks for all the great maths but I have highlighted exactly why it is all meaningless. I have never claimed a similar sized ship, I have always said it would be heavier.

[elouda]

Feb 19, 2019 7:49:12 GMT -6 imryn said:

Feb 19, 2019 7:30:37 GMT -6 elouda said:

Firstly - that 'c. 65,000 tons, 29 kts, 9 x 17" ABL, 24 x 6", 60 x 5", 28" B, 8" D, 28" CT, 29" T, 10" TT, 2" Sec' design is utter fantasy. It is literally breaking the laws of physics. The games calculations don't scale right past 52000tons, and you're trying to cram a lot more ship than Yamato onto the same displacement.

Secondly, to adress the volume thing;

...

Conclusion

You're not going to get the same amount of protected volume on a similarly sized ship with a turtledeck design, unless you make one of the compromises I mentioned in the my first post here, which come with their own issues. You -can- get a smaller, better protected volume for the same weight, but that has its own issues.

I suggest you install the mod and take a look. There is a sticky patch after 51,500 where the calculations for machinery break down but if you move up to 60,000 they work again. If you don't believe my design install the mod and check it out.

I don't need to install it to tell you that that design isn't realistic. It might work in the mod, but that does not mean it isnt fantasy. You can try plug that into a design tool like springsharp or springstyle and see what they give you, but I would wager something around ~80,000t.

EDIT: I went and put a rough version together on springsharp - looks like somewhere around ~86-90kton standard with 1940s tech. I had to assume a few things which I'm not sure how RTW calculates (turret armour other than face?, torpedo bulkhead thickness, etc), but erred on the light side where I could.

Thanks for all the great maths but I have highlighted exactly why it is all meaningless. I have never claimed a similar sized ship, I have always said it would be heavier.

If you aren't comparing ships of similar displacement then the whole debate is meaningless. For every bit of weight you add to your design, you can do the same to an alternative design. If your whole argument is boils down to 'turtleback AoN is possible, but only if I can have ships 35% bigger than anyone else', then its not much of an argument, is it?