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Post by bcoopactual on Jul 10, 2016 11:42:07 GMT -6
Hello all. I was hoping someone could explain to me why the G3/N3/Rodney design was considered advantageous from a weight of armor required for the same amount of protection standpoint. It's never made sense in my head. Let's start with my assumptions: 1. The goal of the citadel is to provide protection for the conning tower, turrets/barbettes/magazines, and propulsion spaces (boiler rooms and engine rooms). 2. Propulsion spaces cannot be located under turrets because of how deep the shell rooms and powder magazines are located.
So, if the length of the citadel and therefore the length of the ship that requires significant armor is the combination of X number of turrets and Y number of boiler rooms and Z number of engine rooms, why does the order they are placed in matter? Why is X-X-X-Y-Z-Y-Z more efficient from an armor weight perspective than X-X-Y-Z-Y-Z-X? What am I missing and where am I going wrong? And does anybody know why the Royal Navy went back to the more traditional 2-A-1 and 2-A-2 configurations for KGV and Lion/Vanguard? Thank you for your input?
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Post by oldpop2000 on Jul 10, 2016 13:36:05 GMT -6
Hello all. I was hoping someone could explain to me why the G3/N3/Rodney design was considered advantageous from a weight of armor required for the same amount of protection standpoint. It's never made sense in my head. Let's start with my assumptions: 1. The goal of the citadel is to provide protection for the conning tower, turrets/barbettes/magazines, and propulsion spaces (boiler rooms and engine rooms). 2. Propulsion spaces cannot be located under turrets because of how deep the shell rooms and powder magazines are located. So, if the length of the citadel and therefore the length of the ship that requires significant armor is the combination of X number of turrets and Y number of boiler rooms and Z number of engine rooms, why does the order they are placed in matter? Why is X-X-X-Y-Z-Y-Z more efficient from an armor weight perspective than X-X-Y-Z-Y-Z-X? What am I missing and where am I going wrong? And does anybody know why the Royal Navy went back to the more traditional 2-A-1 and 2-A-2 configurations for KGV and Lion/Vanguard? Thank you for your input? The main reason for the reversion to conventional layout was cost. The G3 and N3 battleships were going to be 200 feet longer than the Queen Elisabeth class with almost double the displacement. This was more of an investment than the taxpayers could or would afford both in building the ships and upgrading the infrastructure in terms of docks, slips etc. on the Thames shipyards. The primary shipbuilding was already moving to Newcastle on tyne from the Thames due to space requirements for the larger ships. Remember this was post WWI, and the British economy was suffering from inflation and the struggle to get back to a normal economy with the reduction in spending on defense. It was later discovered that by the middle of the 1930's, the all gun forward design was poorly adapted to the installation of HA gun and pom-poms for antiaircraft protection. Due to the blast effect of the larger guns, the AAA guns had to be centered around the after superstructure of the all big guns forward design. The conventional design was able to adapt better to these new weapons requirement with the guns at either end of the ship. There were also changes in armor configuration, armor strength to weight ratio and the addition of the torpedo protection system which essentially increased the distance between the outer hull and the machinery plus magazines. All in all, for these reasons, the conventional design was used, and the larger 18 in. guns were never installed. The conventional design with the 16 and then 15 in. guns were more economically sound investments.
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Post by director on Jul 21, 2016 18:57:59 GMT -6
Well, that's a good question, to which I don't have a ready answer. I did pull up descriptions of the design decisions, consulted Breyer's "Battleships and Battlecruisers" and ran a quick eyeball comparison with the USS North Carolina (a later design with better boiler and engine technology). Armor plans for the Nelson and North Carolina can be googled.
The stated goal of the G3/N3/Nelson design was to reduce the length of the main citadel, limiting the length that had to be armored and permitting maximum armor thickness over the critical areas. I have seen a lot of claims that 3% or more of weight (over 1000 tons) was saved by grouping the turrets together but I have not seen an explanation as to exactly how that was achieved. The closest I came to an explanation was that grouping the turrets together let them save on stiffening the after hull. This would need to be done in a conventional layout to keep the turrets on the same horizontal line - in other words to offset the slight twisting of the hull in a seaway - not dangerous to a ship per se but a serious interference with gunnery direction.
One thing I noticed from studying one drawing of the Nelson layout is that the last twin secondary turret is outside the end of the armored belt, and the rudder/steering motor/screws areas are not armored. Another drawing shows all the secondaries were behind the armor belt, so there's that.
The armored deck was thicker over the turret/magazine areas (160mm) than over the engineering plant (76mm). Breyer says the internal armored belt was not tapered, but putting the engines aft under a thinner deck (knowing the midships area was most likely to be hit) and concentrating the horizontal deck armor on a limited area above the magazines might have saved significant weight, compared to having to keep a thick deck above the engines if they were in the most-likely-hit midships area. Of course, you can't armor everything, and whatever system you expose will probably take an unlikely hit - such is the Murphy's Law of battleship design.
I think it was a 'best case' design strictly of its time, invalidated soon after by advanced weight-reduction and control technologies and by advances in power-plant hp-to-weight ratios. I do think it is telling that the 'all together' grouping was not used in later British designs (also, the last French battleship was intended to have the B turret moved aft). Britain never said the Nelsons were anything but a success, but the ships were never modernized, suffered from engine problems throughout their lives, were unpopular because of the lightweight 16" shell and because the guns tended to wear and droop, and retired before WW2 was over. Perhaps the design involved too many compromises - or as with Bismarck too many advances for all to be successful - or they were simply too radical a departure for a traditional military service, or perhaps they were simply a little flawed and unlucky.
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Post by oldpop2000 on Jul 21, 2016 22:10:38 GMT -6
Well, that's a good question, to which I don't have a ready answer. I did pull up descriptions of the design decisions, consulted Breyer's "Battleships and Battlecruisers" and ran a quick eyeball comparison with the USS North Carolina (a later design with better boiler and engine technology). Armor plans for the Nelson and North Carolina can be googled.
The stated goal of the G3/N3/Nelson design was to reduce the length of the main citadel, limiting the length that had to be armored and permitting maximum armor thickness over the critical areas. I have seen a lot of claims that 3% or more of weight (over 1000 tons) was saved by grouping the turrets together but I have not seen an explanation as to exactly how that was achieved. The closest I came to an explanation was that grouping the turrets together let them save on stiffening the after hull. This would need to be done in a conventional layout to keep the turrets on the same horizontal line - in other words to offset the slight twisting of the hull in a seaway - not dangerous to a ship per se but a serious interference with gunnery direction.
One thing I noticed from studying one drawing of the Nelson layout is that the last twin secondary turret is outside the end of the armored belt, and the rudder/steering motor/screws areas are not armored. Another drawing shows all the secondaries were behind the armor belt, so there's that.
The armored deck was thicker over the turret/magazine areas (160mm) than over the engineering plant (76mm). Breyer says the internal armored belt was not tapered, but putting the engines aft under a thinner deck (knowing the midships area was most likely to be hit) and concentrating the horizontal deck armor on a limited area above the magazines might have saved significant weight, compared to having to keep a thick deck above the engines if they were in the most-likely-hit midships area. Of course, you can't armor everything, and whatever system you expose will probably take an unlikely hit - such is the Murphy's Law of battleship design.
I think it was a 'best case' design strictly of its time, invalidated soon after by advanced weight-reduction and control technologies and by advances in power-plant hp-to-weight ratios. I do think it is telling that the 'all together' grouping was not used in later British designs (also, the last French battleship was intended to have the B turret moved aft). Britain never said the Nelsons were anything but a success, but the ships were never modernized, suffered from engine problems throughout their lives, were unpopular because of the lightweight 16" shell and because the guns tended to wear and droop, and retired before WW2 was over. Perhaps the design involved too many compromises - or as with Bismarck too many advances for all to be successful - or they were simply too radical a departure for a traditional military service, or perhaps they were simply a little flawed and unlucky. I went ahead and put together, using very limited information and my own experience, a Springsharp design for a G3 Battlecruiser dated 1921. The armor, weapons, length, beam, Draught, engine types and power, range etc. are about as close as I can get it. This may give you some reference information for your use. I can probably develop an N3 also, this weekend. My best source is "The Grand Fleet:Warship Design and Development 1906-1922" by D.K. Brown. Note: In this version of Springsharp, the engine calculations are a bit high for the actual speed. If I lock the power at 160000 HP, you get speed of about 30.5 knots, which is close. The only way to get accurate speed of a ship is to test it through a measured mile, both one way, then another, in a harbor. Her original estimate when designed maybe too high.
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Post by director on Jul 22, 2016 7:03:58 GMT -6
There's no question the G3s and N3s would have been terrific ships; they had the size to accommodate the armor, speed and armament. The Nelsons are interesting to me because the design was so tightly constrained by post-Washington tonnage limitations - in effect proving that you couldn't really build a post-Washington battleship capable of handling the challenges WW2 would bring. Even a slight easing of the constraints (3k more tons, or a reduction to 15" main armament) would have made them far more powerful and useful ships.
Of course we have 20-20 hindsight. And if Britain had been able to build the G3/N3 classes the US would have built the inter-war South Dakotas and who knows what else while the Japanese would have built their BBs and BCs and so on and so forth. Naval limitation was an economic blessing for everyone but the US, though some naval construction spending might have mitigated the Great Depression.
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Post by oldpop2000 on Jul 22, 2016 9:10:20 GMT -6
There's no question the G3s and N3s would have been terrific ships; they had the size to accommodate the armor, speed and armament. The Nelsons are interesting to me because the design was so tightly constrained by post-Washington tonnage limitations - in effect proving that you couldn't really build a post-Washington battleship capable of handling the challenges WW2 would bring. Even a slight easing of the constraints (3k more tons, or a reduction to 15" main armament) would have made them far more powerful and useful ships. Of course we have 20-20 hindsight. And if Britain had been able to build the G3/N3 classes the US would have built the inter-war South Dakotas and who knows what else while the Japanese would have built their BBs and BCs and so on and so forth. Naval limitation was an economic blessing for everyone but the US, though some naval construction spending might have mitigated the Great Depression. I have doubts about how well the G3/N3 ships would have conducted themselves in a real gun fight. Human intervention can change all of the best design ideas quickly, we found that out at Jutland. We also can't escape the march of technology, the aircraft was coming and it would have progressed technologically without the Washington Naval Treaties of 1922/1930. Air power would be a game changer. We know the limitations on battleship designs with their guns in the front, they have problems with the placement of AAA on the superstructure. The blast from the main armament would have been astounding to the men in the open tubs of the AA guns. The AAA would have to have been concentrated in the rear superstructure and would have been blocked from attacking torpedo bombers coming in from the front. The only way to alleviate this would be to continuously change course to keep the AA guns aimed in all directions, a difficult task in actual combat. So, my guess is, that those ships probably would have been restricted in the use to certain kinds of operations and would have needed lighter AA ships like AA cruisers for support. However, now we are getting into virtual history. I have never subscribed to the idea that WWII would be a WW1 replay with decisive battles between capital ships without the extensive use of aircraft. It would have been exactly the same because A. Germany would not have built the fleet like the HSF in the 1930's and the US was not going to fight the decisive battle near the Bonin Islands like the Japanese had wished, they knew that by 1935. So, all turned out exactly as it did turn out.
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Post by oldpop2000 on Jul 22, 2016 11:31:01 GMT -6
I found this diagram of the proposed G3 battlecruiser. Maybe we can expand on the discussion with it.
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Post by director on Jul 22, 2016 21:08:57 GMT -6
No-one in the 1920s could forecast what naval combat in WW2 would be like. Their best guess was like predicting the weather - the most statistically likely event is that tomorrow's weather will look more-or-less like today's. So the designers of they day took their best shot at what they thought the important issues would be, and even compared to the American 1920's South Dakota design I think the G3/N3 designs come off pretty well - they are fast, powerful and well protected.
I do agree with you that the shift from battleship to carrier had a bigger effect on tactics and operations than on strategy - given the likely building strategies of the larger industrial nations, their broad naval strategy was fairly easy to predict. But while a massive naval engagement near the Philippines or Bonins was easy to predict, Guadalcanal was not; Germany using commerce raiders was predictable but a naval invasion of Norway was not.
British designs and construction certainly had problems. It is hard for us to determine if they had more issues than other navies or simply were better documented. Other than typical British prejudice against long superstructure-mounted rangefinders I don't see any reason to think the G3/N3 designs wouldn't have performed well in a gun fight. The later design date of the G3/N3 would have let them incorporate war lessons better than Hood (which could only be modified a little) and their generous displacement would have let them avoid the compromises of the Nelsons. So I do think they would have been far better ships than Hood, a refitted Renown and Repulse, or the two Nelsons. With a core of G3/N3 ships, Repulse and Renown could have been converted to carriers and the old 'R' class possibly scrapped.
All battleships in WW2 were limited in the places they could safely go and types of missions they could undertake; these would have been no different. As far as I know, the Nelsons never reported problems with siting the AA guns (though no ship ever had 'enough'); if issues arose from experience they could have been ironed out in a refit. Muzzle blast from big guns was a problem on virtually every battleship from the 1930s on and the usual solution was to keep sailors a certain distance from the big guns. There is only one engagement I'm aware of (Samar) where battleships needed to work their heavy guns and AA weapons at the same time, so that was not usually a problem.
So I don't see anything drastically wrong with the G3/N3 designs. I'd improve the secondary battery and re-site them, and around 1936 give some attention to the AA (perhaps replace the secondaries with some dual-purpose guns), but other than that I'd expect to get good use from them during WW2.
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Post by oldpop2000 on Jul 23, 2016 11:22:29 GMT -6
I have never believed that the dreadnoughts had that much influence on naval warfare in the 20th century beyond the projection of naval power. Of all the battles, major engagements in the early 20th century, I don't believe they affected the outcomes of the wars in substantial way. They would have less influence in the future. It really did not take 20/20 hindsight to see that conclusion.
As to the G3/M3/N3 designs, they had some issues with firing arcs but importantly the unarmored ends of the ship, which could affect stability. The AAA issue did not develop until the mid-1930's but could have been fixed. However, in reality, many military officers and others could see that the days of the dreadnoughts was ended and that the submarine and carrier were going to be the power projection ships of the future; which they still are. I don't feel these designs would have had any real effect on the future of naval warfare because of the rise of airpower and submarines. It would have made no real difference whether there was a Washington or London Naval Treaty because militaries were aggressive in their pursuit of a technology that could effectively sink ships at long range or a technology that could sink ships with stealth. What happened during the interwar years, would have happened no matter how many naval treaties were signed. It's the way militaries work.
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Post by bcoopactual on Jul 27, 2016 18:42:18 GMT -6
Thank you both for the interesting discussion. To your knowledge, did any other navy except for France ever give serious consideration to the all-forward design?
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Post by oldpop2000 on Jul 27, 2016 18:54:24 GMT -6
Thank you both for the interesting discussion. To your knowledge, did any other navy except for France ever give serious consideration to the all-forward design? I have not seen any other all-forward designed capital ships except the British and French. There might have been some preliminary designs by other countries but I haven't seen any. Springstyles book1 which covers 1913-1925 doesn't have any for the US Navy. Russia might have but I haven't seen any such designs.
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Post by director on Jul 28, 2016 7:07:31 GMT -6
There were a lot of preliminary designs. Not sure the US ever seriously considered one but Japan did - I'd have to go to my Breyer's to look up which design, And Japan built the only all-forward cruiser design (the Tone and Chikuma - how geeky is it that I didn't have to look up the names) which used the after part of the ship for a large seaplane hangar. I've learned a lot from this discussion, so thank you for asking the original question. I used a lot of 'all forward' designs in my Byzantium AAR and had very good luck with them. You don't gain much additional tonnage from it but when laying on the armor plate every little bit helps.
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Post by oldpop2000 on Jul 28, 2016 8:22:50 GMT -6
There were a lot of preliminary designs. Not sure the US ever seriously considered one but Japan did - I'd have to go to my Breyer's to look up which design, And Japan built the only all-forward cruiser design (the Tone and Chikuma - how geeky is it that I didn't have to look up the names) which used the after part of the ship for a large seaplane hangar. I've learned a lot from this discussion, so thank you for asking the original question. I used a lot of 'all forward' designs in my Byzantium AAR and had very good luck with them. You don't gain much additional tonnage from it but when laying on the armor plate every little bit helps. The Tone's were specifically designed as scout cruisers, approved in 1934. They were based on the Mogami's. With the requirement of 5 - 6 scout aircraft generally, and the need to fire the guns at the same time, all the guns were moved forward to eliminate gun blast. The weight of armor was the same as Mogami's but the design allowed for a more compact magazine area and heavier protection. It was Tone's scout 5 that was late in launching and missed our carriers at Midway. I have enjoyed this discussion, we should have a general thread on design criteria for warships and discuss armor, engineering, armament, hull design etc. Generally everything we research in the game, might be interesting.
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Post by steel selachian on Jul 31, 2016 21:22:33 GMT -6
There were a lot of preliminary designs. Not sure the US ever seriously considered one but Japan did - I'd have to go to my Breyer's to look up which design, And Japan built the only all-forward cruiser design (the Tone and Chikuma - how geeky is it that I didn't have to look up the names) which used the after part of the ship for a large seaplane hangar. I've learned a lot from this discussion, so thank you for asking the original question. I used a lot of 'all forward' designs in my Byzantium AAR and had very good luck with them. You don't gain much additional tonnage from it but when laying on the armor plate every little bit helps. See the "A" design for what became the North Carolina-class BBs, with nine 14-inch guns in three turrets mounted ahead of the superstructure: en.wikipedia.org/wiki/North_Carolina-class_battleship#/media/File:North_Carolina_class_scheme_A.jpgen.wikipedia.org/wiki/North_Carolina-class_battleshipThis was the only one of the original proposed designs to remain within the 35,000-ton limit imposed by the Washington Naval Treaty; as originally specified it would have been a 30-knot design armored against 14-inch shells with a displacement of 32,150 tons.
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Post by oldpop2000 on Aug 1, 2016 7:32:29 GMT -6
There were a lot of preliminary designs. Not sure the US ever seriously considered one but Japan did - I'd have to go to my Breyer's to look up which design, And Japan built the only all-forward cruiser design (the Tone and Chikuma - how geeky is it that I didn't have to look up the names) which used the after part of the ship for a large seaplane hangar. I've learned a lot from this discussion, so thank you for asking the original question. I used a lot of 'all forward' designs in my Byzantium AAR and had very good luck with them. You don't gain much additional tonnage from it but when laying on the armor plate every little bit helps. See the "A" design for what became the North Carolina-class BBs, with nine 14-inch guns in three turrets mounted ahead of the superstructure: en.wikipedia.org/wiki/North_Carolina-class_battleship#/media/File:North_Carolina_class_scheme_A.jpgen.wikipedia.org/wiki/North_Carolina-class_battleshipThis was the only one of the original proposed designs to remain within the 35,000-ton limit imposed by the Washington Naval Treaty; as originally specified it would have been a 30-knot design armored against 14-inch shells with a displacement of 32,150 tons. Interesting, I have that book and did not look at it. I will today. Thanks for the reminder. Update: The page is from U.S. Battleships by Norman Friedman, Page 246. I've had to upload scan as a zip file for viewing. Attachment Deleted
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