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USS Iowa vs. IJNS Yamato??

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  • #46
    Originally posted by Thorongil View Post
    *The 16" 50 caliber Mark 7 rifles were slightly less as credible at the IJN 18.1 inch having almost as much penetrating power with a smaller gun and a lighter projectile. Plunging fire from an open range would have more then likely easily made up that difference in penetrating Yamato/Musashi deck armor and since the Iowas are faster then can dictate that range in open water. (There are many other factors in this to consider including the machinery,FCR,gun crews etc.) So really Yamato/Musashi really doesnt have that great of an advantage overall to begin with if anything IMO the Iowas in firing cycle alone.

    MK7 can only penetrate about 510mm armor at 20000yards(not meters),and at this range,Yamato`s belt would equal to much thicker than 510mm.And with her Type 94s,she could easily penetrate Iowa`s belt.The only problem is Okun`s Decap thoery,but there is no larger caliber guns test can proof his conclusion in BBs.



    If you want to use MK7 to penetrate Yamato`s horizontal armor,the range must farther than 35000yards.Can you find any hit record at this range?The only one damage record may just belonged to Yamato herself which her near-miss shell damaged White Plain.Oh,by the way,I really want to learn something about the battle of Turk,which Iowa fired upon Sendai.

    *I wouldnt either except nor explain Yamato's armor in any such terms however it would not matter unless you are at point blank range firing at direct horizontal trajectory. Plunging fire does not need to penetrate the turret armor nor belt only the deck armor, bridge armor, magazine for smaller AA guns etc,powerplant or any other vital the ship has. And Yamato/Musashi belt was not as strong as they make it out to be and that has been noted in several books paricularly at the seems.

    You must remeber one thing.In Shinano`s original design,the belt was decreased to 400mm and deck was decreased to 180mm.Why?It was just because the 410mm and 200mm ones were too thick to against US 16in guns though they were equiped with 2700lbs shells.And I don`t need any book to listen me about VH`s quility,because US after-war reports have show it was exellent.


    This can be argued as technology for torpedoes and armor both play big hands in the same outcomes. Japanese torpedo technology was much better at the time of Pearl Harbor and the BB's sitting at Pearl Harbor were not suited to the newer Japanese torpedoes and none of those BB's had conditions (water tight or battle tight) set at the time. They were moored (sitting ducks), having maintence done and being resupplied and well as shore leave so basically very skeleton crews onboard with exception to the Arizona, Oaklahoma and Utah. Musashi and Yamato were caught in the open sea, fully crewed with battle conditions and watertight conditions already set plus they had escorts to protect them and were waiting for the USN planes that were coming. So in short of the two comparisons the Japanese were much better off then the Americans in almost any case argument that can be made bar none to date.

    Moreover,I have got the detailed data of Musashi`s flooding condition when the 6th air raid ended.About 10000tons in each broadsides` unprotected area,7000tons in protected area,7000tons in bow and 1000tons in astern,total weight about 35000tons,all of this data were including the counterflooding waters.And Musashi still held for 5 hours until she sank.Awesome!

    Long Lances, Well, IICR Yamato nor Musashi ever carried them for affixed launchers

    I didn`t say they had.I just meaned the real night battle was the IJN DesRons` job.


    Range and speed, The Iowas in just this simple case have it all over the IJN in other words they have more staying power and can dictate which range to engage at, greater speed also equals faster manuvering.

    Speed is useless in this case if it is a 1 vs 1 duel.It is not a battlecruiser against an armored cruiser.Yamato`s immune zone was far greater than Iowa`s.Speed advantage would just work in this two classes BBs in battleline engagment,but there`s no battleline in 1 vs 1 duel.

    And the range,I cannot get your meaning about this.Why?Because you were saying this while Yamato had greater immune zone and greater gunfire record than Iowa.


    I'm having problems with understanding Yamato's GM? Once you explain the "GM" then I will reply. Please do explain this GM term.

    Higher GM means greater transverse stability and greater ability against capsizal.At the first case,do you remeber the differeces in stability performence between Vanguard and New Jersey in a maneuver?Yamato`s stability was certainly greater than Vanguard`s.
    *Take a look at this table, it discloses Ballistics data, Armor penetration,Destrutive Power, Main battery output and Final gunpower rating. As you will note the Iowas are almost equal. It also makes some critical points although it leaves others out such as maintaining FCR under manuvering which we all know Yamato lacked greatly. We have much accuracy reports on the Iowas but very little on Yamato and Musashi.

    http://www.combinedfleet.com/f_guns.htm

    I.E. as I mentioned above Yamato and Musashi spent more time at anchor then any of the Iowas and you cannot conduct gunnery practice while sitting at anchor, the effects are just not the same and nobody has enough data to truely state how accurate the Yamatos guns actaully were. Pretty much a one sided discusssion you have all the data for the Iowas but pretty much zip on Yamato and Musashi. Until that data ever becomes available it will always be a one sided discussion.

    *By the way Mr. Okun has great articles and references but as times has shown he like all others are not unfoulable to mistake. I do read alot of his articles though very interesting.
    Last edited by Dreadnought; 02 Jun 09,, 14:00.
    Fortitude.....The strength to persist...The courage to endure.

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    • #47
      I am sorry,I don`t think the data which is based on the USN Empirical Formula for armor penetration can adapt to all guns of the world.I would rather to accept the IJN data resource on IJN ships.(The data which is based on the USN Empirical Formula for armor penetration said that Type 94 could only penetrate 495mm armor.But the IJN Technical Department`s file saided it could penetrate 566mm armor at the same range.I would like to believe the IJN one.)

      During the Second Fleet stayed at Linga,Kurita spent a lot of time in gunnery practice(Because they were the main body of Sho-Go Operation).His man also was trained use their No.22 Mod 4 radar to direct gunfire at Linga.And in this period,Musashi got a spread record which was 300m on lognitudinal at the range of 27000m under her commanding officer who was called as Gunnery God(I cannot spell his name in English,the Japanese one was 豬口敏平).

      By the way,Okun`s data of VH was all wrong.For example,he said VH could only equal to about 46% or 43% KC/nA,I don`t know how he could reach this conclusion.

      I don`t know if you have read this.Because I just updata this in my last reply before your reply。So excuse me to write it again

      Moreover,I have got the detailed data of Musashi`s flooding condition when the 6th air raid ended.About 10000tons in each broadsides` unprotected area,7000tons in protected area,7000tons in bow and 1000tons in astern,total weight was up to about 35000tons,all of this data were including the counterflooding waters.And Musashi still held for 5 hours until she sank.Awesome!
      Last edited by Thorongil; 02 Jun 09,, 14:24.

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      • #48
        Ok, about Empiracal data. Since you have seen some of her spread statistics you must have a book. Do you ever remember reading this:

        March 20, 1942 In the Inland Sea, Admiral Yamamato conducted armament trails and they were judged a failure. Both captain Takayanagi and his gunnery officer were called fools because the Yamatos gun aimers manning the rangefinder misread the horizontal settings.
        Last edited by Dreadnought; 02 Jun 09,, 14:25.
        Fortitude.....The strength to persist...The courage to endure.

        Comment


        • #49
          Moreover,I have got the detailed data of Musashi`s flooding condition when the 6th air raid ended.About 10000tons in each broadsides` unprotected area,7000tons in protected area,7000tons in bow and 1000tons in astern,total weight was up to about 35000tons,all of this data were including the counterflooding waters.And Musashi still held for 5 hours until she sank.Awesome!


          *And later judgements found it to be a failure do to the pumping equipment provided aboard was inadequate to deal with the flooding. In other words they depended on the armor protection way too much from her initial fit out and equipment supply. That would not be the first time either, the set you mention above would however be the last time though.
          Fortitude.....The strength to persist...The courage to endure.

          Comment


          • #50
            Originally posted by Dreadnought View Post
            Ok, about Empiracal data. Since you have seen some of her spread statistics you must have a book. Do you ever remember reading this:

            March 20, 1942 In the Inland Sea, Admiral Yamamato conducted armament trails and they were judged a failure. Both captain Takayanagi and his gunnery officer were called fools because the Yamatos gun aimers manning the rangefinder misread the horizontal settings.
            This failure was based on the gunnery aimers` mistakes.Could this kind of failure show Yamato`s main guns spread performence?

            I don`t think so.

            And this pratice was held when Yamato just conmission for 3 months.I don`t surprise in her gunnery aimers`s skill were not good.
            Last edited by Thorongil; 02 Jun 09,, 14:34.

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            • #51
              Originally posted by Thorongil View Post
              This failure was based on the gunnery aimers` mistakes.Could this kind of failure show Yamato`s main guns spread performence?

              I don`t think so.

              And this pratice was held when Yamato just conmission for 3 months.I don`t surprise her gunnery aimers`s skill were not good.
              What it relates is experience. You can have the biggest guns in the world but if you dont have accuracy then it doesnt equate to much at all.

              http://www.fas.org/man/dod-101/sys/s...709176_jpg.gif
              Fortitude.....The strength to persist...The courage to endure.

              Comment


              • #52
                Originally posted by Dreadnought View Post
                What it relates is experience. You can have the biggest guns in the world but if you dont have accuracy then it doesnt equate to much at all.

                http://www.fas.org/man/dod-101/sys/s...709176_jpg.gif
                I remeber this practice was held in 1980s(If I`m wrong,I`m very glad you to point me about my mistake)...I have seen it before,and got conclusion that it`s not meaningful for a WWII duel.



                Excuse me,do you have some data about the battle which Iowa fired upon Sendai?Maybe we can compare it with Yamato upon Taffy III,and then wo can get an undoubtful conclusion.
                Last edited by Thorongil; 02 Jun 09,, 14:42.

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                • #53
                  Originally posted by Thorongil View Post
                  I remeber this practice was held in 1980s(If I`m wrong,I`m very glad you to point me about my mistake)...I have seen it before,and got conclusion that it`s not meaningful fot a WWII duel.
                  Yes it was but with the very same ammunition and gunpowder. Basically what Im trying to relate is accuracy. The Iowas even did better as time moved on. If you would like I can run you links to birds eye views as to the accuracy of the gun going back as far as the Korean era. Same exact powder, same exact projectiles and just like the condition of Yamato and Musashi's guns as far as wear is concerned since the majority of the Iowas were not regunned until after the Korean War. IMO its all in the training and accuracy of the crews and how well then blend together.
                  Fortitude.....The strength to persist...The courage to endure.

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                  • #54
                    Originally posted by Dreadnought View Post
                    Yes it was but with the very same ammunition and gunpowder. Basically what Im trying to relate is accuracy. The Iowas even did better as time moved on. If you would like I can run you links to birds eye views as to the accuracy of the gun going back as far as the Korean era. Same exact powder, same exact projectiles and just like the condition of Yamato and Musashi's guns as far as wear is concerned since the majority of the Iowas were not regunned until after the Korean War. IMO its all in the training and accuracy of the crews and how well then blend together.
                    The post-war Propellant Charge was changed,and with different fire control system.It just like difference between F-14A and F-14D...They`re all Tomcats,but not the same one.

                    664.6 lbs. (301.5 kg) NC (WWII)
                    319.6 lbs. (145.0 kg) NC (WWII reduced charge)
                    659.6 lbs. (299.2 kg) SPD (Post-WWII)
                    325.0 lbs. (147.4 kg) SPD/N/CG (Post-WWII reduced charge)



                    A persistent anecdote is that the Iowa class suffered from alignment problems until after the Battle of Leyte Gulf. William Jurens, a noted expert on US naval weaponry, together with Iowa crewmembers and the staff at NSWC Dahlgren, performed a search of the official records for detailed data on this specific problem but could find nothing in the files suggesting that the alignments were in any way out of the ordinary. Mr. Jurens' suspicion is that there may have been an oblique reference to an alignment problem in some document that was taken out of context; perhaps they were waiting for parts.
                    Last edited by Thorongil; 02 Jun 09,, 14:59.

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                    • #55
                      A persistent anecdote is that the Iowa class suffered from alignment problems until after the Battle of Leyte Gulf. William Jurens, a noted expert on US naval weaponry, together with Iowa crewmembers and the staff at NSWC Dahlgren, performed a search of the official records for detailed data on this specific problem but could find nothing in the files suggesting that the alignments were in any way out of the ordinary. Mr. Jurens' suspicion is that there may have been an oblique reference to an alignment problem in some document that was taken out of context; perhaps they were waiting for parts.

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                      That anecdote is about as true as USS Missouri's keel being bent when she grounded. In other words baseless and without fact.;)
                      Fortitude.....The strength to persist...The courage to endure.

                      Comment


                      • #56
                        Originally posted by Dreadnought View Post
                        A persistent anecdote is that the Iowa class suffered from alignment problems until after the Battle of Leyte Gulf. William Jurens, a noted expert on US naval weaponry, together with Iowa crewmembers and the staff at NSWC Dahlgren, performed a search of the official records for detailed data on this specific problem but could find nothing in the files suggesting that the alignments were in any way out of the ordinary. Mr. Jurens' suspicion is that there may have been an oblique reference to an alignment problem in some document that was taken out of context; perhaps they were waiting for parts.

                        --------------------------------------------------------------------------

                        That anecdote is about as true as USS Missouri's keel being bent when she grounded. In other words baseless and without fact.;)
                        I`m bothered by this paragraph for a longe time(Actully,I cannot understand entire meaning of it.I was used to believe it was said Iowa class have a fire control problem and without solution) .It looks like my ability of English must be improved much...
                        Last edited by Thorongil; 02 Jun 09,, 15:10.

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                        • #57
                          Originally posted by Thorongil View Post
                          I`m bothered by this paragraph for a longe time(Actully,I cannot understand entire meaning of it.I was used to believe it was said Iowa class have a fire control problem and without solution) .It looks like my ability of English must be improved much...
                          *Dont be bothered, most experts are not bothered by that. My meaning, The Iowas conducted gunnery long prior to Leyte and there are writings by gentlemen that were there to see the practice. The Iowas suffered no hits during the Leyte Ops that would either impeed her gunnery or her FCR. One could imagine though teething problems with updated fire control, stabile verticle etc after being refitted although I would have to check on how many refits were recieved during WWII. Iowa and New Jersey would have been the first since joining the fleet in 43. Missouri and Wisconsin didnt join the fleet until 44.

                          *As opposed to the anecdote, There are still many that write that Yamato only had fuel for a one way trip to Okinawa when in fact men that were aboard her state quite differently and she did in fact have fuel for a round trip to Okinawa. All depends on who is doing the writing and where they get their facts from.


                          On March 29, 1945, an order arrived for Yamato at the Navy's Kure Harbor to sortie toward Okinawa, but everyone knew that the giant battleship and nine smaller ships stood no chance against a much stronger enemy. Yasugi had the opportunity to spend one night at a Kure inn with his mother before Yamato left port for Tokuyama Harbor (Yamaguchi Prefecture), where Yasugi states that the ship received enough fuel for a round-trip to Okinawa despite many sources that still claim the battleship had enough fuel for only one way.

                          Yasuo Yasugi was there and stated this numerous times although many writers ignored these facts.
                          Last edited by Dreadnought; 02 Jun 09,, 17:30.
                          Fortitude.....The strength to persist...The courage to endure.

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                          • #58
                            Originally posted by Dreadnought View Post
                            There are still many that write that Yamato only had fuel for a one way trip to Okinawa when in fact men that were aboard her state quite differently and she did in fact have fuel for a round trip to Okinawa. All depends on who is doing the writing and where they get their facts from.
                            That`s right.Yamato carried 4000tons fuel when she began the Ten-Go Operation.It could made her had an endurance of about 4500-5000nm at 16kts.

                            And some of the other ships,Yahagi carried 1250tons,Isokaze carried 599tons,Yukikaze carried 588tons.

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                            • #59
                              "GM" is called "metacentric height." It is the measure of the line segment connecting the height of the ship's center of gravity (G) up to its metacenter (M), which can be conceived as the axis around which the hull rolls. It is used as a handy indicator of the ship's stability, usually in an undamaged state. Once the damage begins, things gets more complex. GM is often correlated with the ship's beam--two ships with the same GM but different beams will react very differently to flooding. This is one reason I'm not very impressed by old battleships that have been bulged to exceptionally great breadth. If you extended your arm and I hung a 15-lb weight to it just a couple inches down from your shoulder, you could keep your arm up for quite a while; if I hung it just a couple inches up from your wrist, that would be another matter. So beam for its own sake is nothing to crow about, and GM in damaged condition is a truly complicated subject. I think you can see this in Kirishima's loss--the ship's own command personnel appear to have been unaware of the effects on her GM, which had sunk to a negative value (her G was actually above her M) and thus hastened her sinking.
                              We should note that stability and steadiness are not the same thing at all; in fact, they tend to be mutually exclusive. This is the reason why the British deliberately designed the "R" class battleships with less stability than the preceding Queen Elizabeth class; the "R's" were meant to be steadier gun platforms. And again, GM and beam interact closely in this.
                              At full load, Vanguard had a GM of 8.2 feet. Iowa had a GM of 8.4 feet at full load. Both had a beam of about 108 feet.
                              I'd be very interested in knowing which source claims Yamashiro suffered only two battleship-caliber shell hits in Surigao Strait.
                              The comparative shell resistance of VH and Class A will vary with the caliber of the incoming shell. VH is actually superior to Class A against the largest shells (Yamato's).
                              Iowa is capable of piercing Yamato's deck at around 30,000 yards if the crew uses a reduced charge which gave the same performance as the NC/SoDak 45cal gun. The FC system was set up to allow this option. This doesn’t change the fact that Yamato has an IZ to Iowa's gunfire while the Iowa is vulnerable at pretty much all ranges.
                              It was generally held in the USN that a battleship's speed in a gun duel was largely irrelevant unless the ship wanted to flee.
                              The USN was also aware that its use of the Thompson F formula for armor penetration did not precisely model penetration of face-hardened armor (it was developed for homogenous armor), but it was deemed close enough for the specific criterion they used in formulating protection systems. I’m not sure if that’s correct even in this very specific application. Fortunately, we can go way beyond that with more modern formulae like Nathan Okun's.
                              I think the reference to Iowa and Sendai is meant to be Iowa and Katori. Unfortunately, Iowa's action report gives no specifics of the sort we would most like to see. It mentions no hits in particular but does credit Iowa’s 16in shells as a cause of the ship’s loss. Katori was literally a sitting target, and the fact that all Iowa's salvos were straddles is not that significant.
                              I have not found any strong indicators on the maintenance of gunnery skills for the Yamato crews. What I have seen seems to indicate a very limited amount of gunnery practice. How often did Yamato and Musashi practice?
                              I agree that the claim of excessive dispersion in Iowa's guns (first published in Friedman's US Naval Weapons) now appears to be mistaken.

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                              • #60
                                Re the number of hits on Yamashiro at Surigao, here's an extract from West Virginia's battle report:

                                The gun fire from this vessel was very effective. There were possible and probable hits in all salvos. Three pronounced flareups were observed on the target at the splash time of our 1st, 2nd, and 6th salvos. The 4th salvo seemed to be particularly concentrated on the target. The MK 8 radar operators had no difficulty in identifying or spotting our salvos. Splashes from other ships were observed but did not interfere except on the 5th salvo. It was possible to distinguish between our own and other ship's salvos by the size of the individual splashes.

                                and:

                                Enemy Battle Damage --
                                At the time of the splash of our 6th salvo when a distinct flare up was seen there were three officers and three enlisted men who saw the silhouette as a Japanese battleship by the characteristic construction of its foremast but could not definitely determine her class. Due to the fact that she was heavily pounded with 16 inch projectiles and that she disappeared from all radar screens at 0412, it is certain she was sunk. Later reports verified the sinking of one or more battleships

                                It suggests that Yamashiro was hit by more than 2 or 3 US BB shells.

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