So can someone explain to me what's wrong with yubari ? I only understand(guessing) that he make Light Cruiser with same firepower like Heavy Cruiser, is this right ?
So can someone explain to me what's wrong with yubari ? I only understand(guessing) that he make Light Cruiser with same firepower like Heavy Cruiser, is this right ?
Not really, but she carries more firepower than a ship of her displacement usually can at that time. IIRC this actually overload her or something and has slower speed compare to other cruisers with her displacement.
Edit: Oh and, at that time, cruiser's displacement is limited by the Washington Naval Treaty.
So can someone explain to me what's wrong with yubari ? I only understand(guessing) that he make Light Cruiser with same firepower like Heavy Cruiser, is this right ?
Yuubari was an experiment cruiser designed by the IJN to become a test bed for several new Japanese technologies, because of her compact design which compressed firepower and armor with average speed (35.5 knots), she pioneered the Japanese designs for light cruisers and destroyers in the future which were effective fast hitters.
And beside the Japanese was still restrained by the Washington Naval Treaty to build more powerful cruisers.
Basically Yuubari has the firepower of a Sendai on a hull that is almost half the tonnage. While this didn't lead to more like her, it did lead to Fubuki, a destroyer that had the firepower of a older light cruiser.
Well you know aside from: -She didn't weigh 3,100 tons. 3,100~ tons at full load was design goal, this proved absurd and completely impossible she was already nearly 3500 when launched and by the time strengthening, ballasting, and other additions were made she was at nearly 4,000 tons by the time she saw combat. The 5,500 ton types did not by and large see the same inflation, coming in close to design weight to start with and needing less strengthening and ballasting afterward. There performance thus stayed closer to design goals during their service life. -35.5 knots was also her 'design' speed, but because she emerged overweight straight out of the yard she never made this and it only got worse with the above changes, by the time of the war her bloated weight (nearly 25% over design!) made her pretty easily the slowest of the cruisers in service, she struggled to make 32 knots. -For pretty much the same reason her range was also badly degraded and much less then the 5,500 ton ships, it was so poor in fact it was less then the DD she was supposed to be leading! -The 'armor' was so thin as to be effectively worthless and was weaker then even the marginal plating of the 5,500 tonners. It wouldn't even reliably resist shell fire from a DD, even if it had been installed properly, which it wasn't. In a failure of basic geometry that boggles the mind someone decided to slope it INWARD so that the impact angle of incoming (plunging) shell fire was actually normalized reducing it's effective thickness over even if it had just been installed as a vertical slab. About the only thing the armor was useful for was making sure that enemy armor piercing ammunition would encounter enough resistance to reliably initiate inside the ships vitals. -The armor was also made load bearing structure as a weight saving measure. This might seem logical (armor is strong!), but it's a debatable choice for the simple reason that armor is expected to sustain impacts that will likely deform and warp it even if it resists outright penetration. If it's hung on an independent underlying structure this is fine, but if that now warped and weakened plating IS the structure... well the issue here is rather obvious. Even if this doesn't result in a structural failure that causes the ship's outright loss it still meant any damage to armor was also automatically structural damage complicating repairs considerably even if the armor manages to stop penetration.
Overall Yubari was largely unimpressive in all areas besides the weight of weaponry for her displacement, but Japanese cruiser weapons were small at only 140mm so even that is deceptive, she was very weak for a 'cruiser'. In fact several "large DD/CLs" basically matched or even exceeded her weaponry at similiar displacement (largely by dispensing with the useless armor). In all other areas though she was mostly a compromised design too short ranged for the intended role as a DD flagship, also too slow for the job, her 'armor' quite possibly worse then useless, and her heavily integrated structure making any damage much harder to repair.
Some aspects of her design would later be used on following Japanese cruisers, but I've always considered those ships monstrously overrated so I hardly automatically count that as a good thing. Ships of her type though were clearly a dead end, combing basically the worst aspects of a DD with very few of the strengths of a cruiser.
Basically Yuubari has the firepower of a Sendai on a hull that is almost half the tonnage. While this didn't lead to more like her, it did lead to Fubuki, a destroyer that had the firepower of a older light cruiser.
However from Yuubari, she become the basis for the Aoba and Furutaka-class.
Some aspects of her design would later be used on following Japanese cruisers, but I've always considered those ships monstrously overrated so I hardly automatically count that as a good thing. Ships of her type though were clearly a dead end, combing basically the worst aspects of a DD with very few of the strengths of a cruiser.
Care to follow up on this?
What makes the cruisers that followed her overrated? (Isn't it just the Agano class and Ooyodo?)
What makes the cruisers that followed her overrated? (Isn't it just the Agano class and Ooyodo?)
Where to start might as well break it down by category I suppose (this all applies to basically all the "big" cruisers from Myoko to Mogami to one degree or another, not a shock given that the three classes covered where fairly linear incremental improvements):
You asked for it...
Protection:
They included a large longitudinal bulkhead (in other words a bulkhead that ran fore to aft) good for stiffening a hull and theoretically containing flooding to one side of the ship. Bad since it allows one side to flood unevenly risking more rapid capsizing and listing.
This was deemed needed largely because the machinery was not well separated. The engine and boiler rooms were each clumped together meaning a hit in either could theoretically flood or damage the entire space and stop the ship dead. (Admittedly the last pre-war US classes also went back to this arrangement too in an attempt save hull length.) The bulkhead was a somewhat suspect attempt to overcome this by dividing these spaces down the middle. The wisdom of allowing such a large space to flood so unevenly is questionable and indeed the lead designer opposed it, but was overruled.
This then lead into a rather questionable obsession with counter flooding to combat this problem, but if one was simply going to flood other spaces to maintain trim the entire point of the centerline bulkhead starts to look rather dubious.
Their armor was also often structural in order to try and shave weight, why this is a questionable idea was already covered.
The armor was still very weak in a number areas the turrets were effectively protected only from splinters by 25mm RHA plate that DD fire could penetrate at battle ranges. The barrettes were barely better. US cruiser turrets by contrast had thick protection largely proof against their own weapons.
The deck armor was also weak averaging about 30-35mm, most US cruisers had at least 50-65mm. The Tone is the only exception, but only over the magazines which had a good 56mm top, her machinery protection remained a weak 31mm. (Ignore quotes of Mogami having a 50mm+ deck, this actually covers only a small plate connecting the armor deck's edge to the top of belt over the machinery. In any case due to this plates downward slope it would normalize the impact angle of incoming projectiles reducing effective thickness, the extra thickness is likely compensation for this fact, Tone also shared this feature over her machinery section.)
The belts were probably their best protective feature, and changed the most across the classes getting progressively thicker, but ONLY abreast the magazines.
The Myoko was a uniform 100mm, but it was somewhat inclined. This probably made it slightly better then most mid 30s ships, but as other ships began mounting 5 inch belts or thicker it lost most if not all of that advantage.
The Takao boosted thickness to 125mm~ over the magazines (although one line in the rather definitive Japanese Cruisers of the Pacific War seems to indicate these thicker belts might not have been inclined, sadly no hull sections at the guns are included for this class).
Mogami went up to 140mm and Tone to 145mm abreast the magazines, and sections in the aforementioned book show that these belts were inclined. Although the inclination was increased somewhat on these last two classes providing a modest increase in side protection to the machinery even though thickness remained 100mm.
The magazine sections from Takao onward were probably among the best protection on any cruiser, but it was somewhat comprised by the total absence of turret or barbette protection from cruiser fire. The thick armor was also needed due to the magazines position fairly high in the hull with tops at about the waterline.*
In the late 30s and war era US cruisers (along with the later Italian cruisers) began utilizing face hardened armor for belt and turret protection. All steel is not created equal and against cruiser caliber shells this was a vastly superior material. This was only compounded by the fact thickness increased to around 150mm on the Witcha and Baltimore, and 140-130mm on the Brooklyn and Cleveland whose belt was also slightly inclined.(It's unfortunate this plate was not available in time for use on the prolific mid-30s New Orleans class.) Japan never deployed any face hardened plate on a non capital ship due to the difficulty of production and as such even with the increased incline of Mogami and Tones belts it's side protection had definitely become inferior by about 1940 compared to new US cruisers.
As noted later the Japanese had become rather obsessed with diving shells, they thought others would be too and so they began incorporating large tapering 'lower belts' all the way to their ships double bottoms in the Mogami and Tone class. All this really did was add useless extra weight and compromise what torpedo protection the ships had. (It wasn't appreciated at the time, but the very stiff backing of an armor plate compromised TDS systems that by necessity relayed largely on plastic deformation to absorb energy. The US Fast battleships after North Carolina also had this defect due to having adopted lower tapering belts for similar reasons, Montana would have featured a modified design that eliminated this feature)
As a cost cutting measure some bulkheads, protective plating, and structural elements were produced from lower grades of high tensile steel rather then what other nations would consider true 'armor grade' material. The US meanwhile was using scads of RHA equivalent STS all over it's later ships. This effected some of the older Japanese battleships worse though Nagato for instance when examined post war was considered by the USN to not technically have an armored deck over her machinery since she had only fairly mundane high tensile steel plating over it.
The torpedoes were outside any armor protection and consequently a huge liability.
Machinery and Hull:
That machinery wasn't that greater either, temperature and pressure were unimpressive by US standards it was also bulky leading to large machinery spaces, this likely then drove the feeling that some further form of subdivision within the space was needed in the form of the center-line bulkhead in addition to increasing armored volume.
This was compounded by the ships being way overpowered due an obsession with uselessly high speeds, foreign designs came within 2 or 3 knots for on the order of 30 to 50% less power with the expected weight and volume savings.
The call for ridiculous top end speeds also forced a high length to beam ratio as well making the ships even longer still driving up weight and stressing the lightly built hulls (most obviously seen on the Mogamis).
The result of all this was a very long ship with large machinery which resulted in a larger volume that needed to be armored, with the ships already overweight there was little weight to spare and this likely largely explains their decidedly average protection given their displacement.
And these designs were seriously overweight in most cases, at light loads they were considered unstable and had to be ballasted. The result was that these ships were effectively maxed in displacement upon leaving the shipyard. There was for instance plans to produce and bolt much heavier face plates to the turrets, but this was never done as their was simply no stability left in the designs.
The high power, comparatively less advanced machinery, and overweight conditions also produced unimpressive cruising ranges on the order of 25 to 30% less then US cruisers of the same age carrying similar to even somewhat less fuel oil.
Weaponry:
The use of a large farm of twin turrets was also wasteful and inefficient in terms of space. It resulted in extra magazines and shell handling equipment driving up the armored volume and weight even further. The firing arcs on the aft most forward gun was also quite frankly terrible. The arrangement on the Tone class was worse still. The US use of triple turrets resulted in 90% of the firepower from 40% fewer turrets and better arcs. This was also likely a contributing factor to why the Japanese ships had turrets and trunks protected by cardboard.
The obsession with diving shells produce a suboptimal AP shell since some compromises were made to produce a more stable underwater trajectory. This appears to have worked as hoped exactly once during the entire war and also instantly showed why it was probably a dumb idea to start with. An 8 inch shell just barely slipped under the bottom of the enemy belt into a magazine as hoped... and the water rushing in through the necessarily submerged breach smothered the fire before it caused an explosion. Opps.
In the same battle against the same ship it further demonstrated how this trade off wasn't even close to worth it when the same shells bounced off a six and a half inch turret face plate at under 10,000 yards. The turret was not effected and the guns in it continued firing. Another hit lodged in the six inch barbette armor of a second turret freezing it, but failing to penetrate and explode within. Against any Japanese cruiser both of these shells would have been assured penetration and high order denotations and would have probably burned out both turrets at minimum.
The super long delay needed to keep the shells from exploding during a long underwater trajectory was also a problem. At Augusta Bay for instance two 8 inch shells passed through large (unarmored) portions of USS Denver above the water and out the far side and failed to explode within the ship (also showing all or nothing armoring in action). Either due to the long fuse delays or the insensitive nature of the fuses (also needed to keep them from per-maturing on water impact).
Honestly just everything about the Japanese shells was bad, bad, bad. They were pretty easily the worst designs in wide use by any navy in the war. (The US shells were coincidentally the best, rather showing off the two nations technical focus pre-war)
The Long lance was more dangerous to the cruiser then the enemy by most indications. This deserves its own explanation honestly since it seems so unintuitive.*
AA battery was weak compared to the war built US cruisers (50% fewer heavy AA guns on the broadside) although it was about as good as the late 30s US designs and better then most other pre-war ships. The bigger issue was that the designs had so little margin in them that it was largely impractical to try and improve it despite the ships bulk during the war. This is evident with Maya who when fitted with improved AA weaponry lost numerous other weapons in return.
High angle fire control was poor in any case, radar directed AA was never attained and in fact the automatic weapons had no computing director control whatsoever. This as much as the marginal caliber probably amply explains their woeful ineffectiveness.
They also never obtained useful integrated radar fire control against surface targets. The extent of their capability was that the guy working the radar late in the war could verbally give the plotters an estimated range, but the comparatively primitive Japanese radars had such an uncertainty factor (plus of minus hundreds of yards) that this was useful in only the most general terms.
This is not to say they were awful ships at all mind you, but people often seem to just act like all other cruisers paled before them and that the lack of radar was their only real issue. Certainly they had their strengths, but they had some pretty glaring weaknesses too. In my view the US and Italy produced better overall designs from a technical stand point. (With the US being the clear winner in terms of doing the most while acting in good faith regarding the treaties.) Both Italy, Germany, and Japan cheated treaty limits pretty heavily, by accident or design, yet I don’t think Japan benefited from that cheating as much as it could have with a better design philosophy (still better then Germany though the Hipper was a complete turd for such a massive cheater cheater). I'm dead certain that if the US designers had been willing to simply allow their designs to spiral thousands of tons overweight when the limits became inconvenient like the Japanese did or willing to outright lie like Germany and Italy they would have produced much better ships, given that as it was they'd already produced arguably superior designs within the treaty limits.
My own personal list of ships would be*: Best Classes: Zara, Baltimore, Deutschland (I actually like the Duestschlands allot I think with a few thousand more tons for more effective armor and slightly more speed they would've been world beaters, as it was they were close. I think the 'very large gun, marginal armor' solution in general was a better design paradigm for a 10,000 to 15,000 ton ship to be able to contribute in a fleet action and that without treaty limitations 11 to 12 inch guns would've become the standard 'armored cruiser' battery of the inter-war years.) Very Good Classes: Witcha, Cleveland, Algerie, St Louis, Mogami (only after the last and most extensive rebuild) Good Classes: Brooklyn, the rest of the large Japanese CAs (Despite some improvements I don't like Tone's layout and Japan didn't either seeing as Ibuki was basically a repeat Mogami), Hipper, New Orleans, Town Class, Duca degli Abruzzi (placed here mostly due to a lack of detailed sources I can find, depending on what those might reveal it could go to very good) Compromised Classes: Any large ship is dangerous, but these vessels where clearly sub-par County Class, Aoba, Furutaka, anything US before New Orleans(the Portland being perhaps debatable), Italian ships besides Zara and Duca, pretty much anything French before Algerie.
*I'm excluding Des Moines as a post war class, but if included she'd be in a class of her own.
* Note on magazine placement
Some later US cruiser might seem at a glance to have weaker side magazine protection, this however is because the US moved it's magazines lower into the ship on later designs leveraging water as part of side protection, another example of using clever design instead of brute force. The tops of the forward magazines on most late 30s and war era US cruisers were 5 to 6 feet underwater at design weight, the Japanese magazines tops were at to slightly above the waterline for comparison. Because of the shafts the aft magazines on US ships had to be placed higher, but where still slightly lower then the Japanese ships and slightly submerged. These received about 120mm of protection due to the lack of water to slow incoming shells however.
* Regarding damage to Japanese cruisers from their own torpedoes and torpedoes on cruisers generally
The sum total then for IJN heavy cruiser torpedoes in WWII seems to be 1 DD (Kortenaer), 2 CL (Java and De Ruyter) and 1 CA (Vincennes). Some strike must also be given for the fact that cruiser torpedoes also sank five friendly vessels (four transports and a minesweeper) during Sunda Strait.
By contrast the following Japanese cruisers suffered damage that probably contributed to their sinking from their own torpedoes: Chokai: either shell of bomb fragments set off her torpedoes at Samar the resulting blast centered aft as it was knocked out all propulsion forcing a scuttling Mogami: While she had extensive damage already the final death blow was fire reaching torpedoes that couldn't be accessed due to said fire and devastating her remaining machinery Mikuma: GP bombs that failed to penetrate the deck readily set off torpedoes aboard and with similar results to Chokai knocked out her machinery ending any hope of escape Suzuya: Bomb fragments set off a torpedo in the tube, which in turn set off a chain reaction that crippled the ship Furutaka: Shell hits started a fire that set off her torpedoes. She was taking allot of shell hits already (and later took a torpedo proper) so her survival was already questionable, but this certainly 'sealed the deal' and it still demonstrates the vulnerability during a surface action. Aoba: A bomb hit set off torpedoes; the resulting blast tore open the ship's side so badly it sunk with only beaching allowing her to be later salvaged
There were other near misses as well; Mogami decided to jettison her torpedoes before she came under air attack at Midway. This move probably saved the ship given the bomb hits she sustained in the area shortly their after. Chikuma likewise was saved by a damage control officer taking it upon himself to jettison here-to-fore undamaged torpedoes during an air attack. A bomb landed almost directly on one of the mounts minutes later and could’ve easily killed the ship if not for this call.
So during the war five Japanese cruisers had their torpedoes heavily aggravate damage if not outright cause their sinkings, and at least two others escaped it by the skin of their teeth by ditching the weapons preemptively when they came under attack (a tactic that seems somewhat unworkable if one hopes to use them during a battle!). Keep in mind that Japan had only 17 heavy cruisers during the war meaning nearly a third of the fleet was at least partly destroyed by their own weapons. One more was sunk, but in water shallow enough to be salvaged, and at least two more were saved only be jettisoning them when under attack. Thus the danger of oxygen torpedoes on a cruiser cannot simply be shrugged off. Keeping the weapons on board when under bomb or artillery attack is clearly a major risk that also negates some of a cruiser’s durability against smaller weapons by providing something a ‘lucky hit’ or even mere fragments can turn into massive damage.
The lack of enemy kills to show for this is rather damning but also entirely predictable.
The primary purpose of a cruiser, unlike a destroyer, is to bring it’s battery of guns to bear on enemy ships. The best way to do this is to maintain a reasonable distance and fairly steady course to facilitate a good gunnery solution. Torpedo attacks require a very different profile. The effective range of torpedoes is much less then cruiser gunfire and more or less requires a fairly direct approach course in order to close to effective range. If the enemy simply holds his formation and fires as you come on you’re effectively granting him a crossed T as while simultaneously reducing the range virtually assuring you’ll be taking more hits.
A note here in counter to the usual “long lance outranges a battleship!” stuff: It doesn’t. The maximum theoretical mechanical range and maximum effective range are different things. Wartime experience showed the huge effort put into torpedo range by the Japanese was largely a waste of time. The number of hits scored at ranges beyond those Allied torpedoes could’ve reached can be counted on your fingers. The long lances greatest asset proved actually to be its somewhat higher speed at the 'short' range setting which made it more accurate within effective torpedo range and a very large warhead that made it very deadly if it found it’s mark.
Effective torpedo range was in fact well below almost any gun range. A very good illustration of this is Captain Hara memoirs and in particular his discussion of a number of destroyer actions in the Solomon’s in 1943. He talks about torpedo shots at 10-11,000 yards as being effectively wastes of ordnance with almost no chance of success on an alerted enemy, and with good reason as these massed long range salvos basically never achieve shit. He further talks about considering ideal range for even the Type 93 being a mere 3,000 yards with 6 to 7,000 being workable with a good firing position.
Even the later isn’t half the effective range of a six inch cruiser, it’s barely a third of an eight gun ship.
Thus even with the long lance real results were only obtained during comparatively close launches which were doctrinally against what a heavy cruiser is supposed to be doing, if for no other reason then that trying to close range would make the much larger and less agile cruiser highly vulnerable to torpedo attack itself. Certainly torpedoes were deadly, but that death was coming from submarines, airplanes, and destroyers (in that order), aka platforms that could get close to launch, not cruisers. It's interesting to note that by WWII cruisers where engaging at ranges similar to WWI battleships which had not long after the war already been determined to be so long as to render torpedoes on said battleships basically deadweight.
I thus don't consider a lack of heavy torpedo weaponry to be a particular problem for a cruiser, even less so if the saved weight (torpedoes and tubes combined tended to weigh nearly as much as a DP mount) is utilized for a heavier AA battery which only increased in importance as time went on while surface torpedo attack was already almost extinct even among DDs by the late 40s.
It'll be cheap if it's small!Ah? I didn't say that much...Thanks for waitin'.Ship architect mastermind, Hiraga Yuzuru.The worldwide depression and the inflation... Can't you build warships cheaper?Naval bigwigWe wouldn't be suffering if it was possible.It's all right. It's complete!!No need to be pretentious...I'll make a 3000 ton cruiser with the weaponry of a 5500 ton!!It didn't just surprise Japan. It surprised the entire world.What the heck is she?It's Yuubari!WHHHAAAT??!??Yuubari is doneLeave it to me, young'un!3100 ton displacement with the combat potential of a 5500 ton! It's fast and it has armor!