User talk:Shibumi2/Archive1

Replacing metric units with English
Hello! I've noticed that you're making updates to various articles about Japanese ships. In many cases, like here, you're replacing metric units with English ones. I am not sure what units were used to engineer Japanese ships, but I know that their armament was engineered in metric units, and so the metric units should come first with an English conversion following. TomTheHand (talk) 23:22, 4 December 2007 (UTC)

Akagi and Kaga
Please stop saying that Akagi and Kaga retained battleship barbettes after they were converted to carriers. This is plainly false, as these diagrams show.

http://www.voodoo.cz/ww2car/schems/akagi.jpg

http://www.voodoo.cz/ww2car/schems/kaga.jpg

Orpy15 (talk) 05:15, 19 December 2007 (UTC)


 * Your information is false and you have failed to provide any citation that could have supported it. The jpegs above clearly show that no large barbettes remain. Please stop introducing false information to these articles. Orpy15 (talk) 02:51, 27 December 2007 (UTC)


 * Sorry, but your assertions are incorrect on almost every level.


 * 1. The initial conversions were complicated and extensive. They took several years, beginning in 1923.  Akagi was not completed until 1927.  Kaga not until 1928. Far from just laying a "wooden deck" over the hull, Akagi and Kaga received two full hangar decks and two flying off decks at the bow. The ships also received 2 8-inch gun turrets.


 * In the case of Akagi, this resulted in three separated, vertically arranged flight decks: an upper landing deck 624 feet (190 meters) in length, a middle flying off deck for fighters 60 feet (18 meters) long, and a 160-foot (49-meter) flying off deck beneath that for launching torpedo bombers. [] [] As you can see, the result was quite elaborate.


 * Why do you think that two hangar decks and large 8 inch gun turrets, which took several years to build, could be "quickly stripped off"? Look at this picture showing the massive structure necessary for two hangar decks. [] How could that be "quickly stripped off"?


 * 2. You assert that the initial conversion simply added a "wooden deck" for airplanes to land on. This is absurd. No operational aircraft carrier has ever had just a "wooden deck." Akagi and Kaga, like almost all carriers of that era, used wood PLANKING (45 millimeters thick) over a STEEL deck (7 millimeters thick). See "The Unknown Battle of Midway: The Destruction of the American Torpedo Squadrons" by Alvin Kernan.


 * 3. During the initial conversion, Akagi's belt armor was reduced from 10 inches to 6 inches. Why would the navy have reduced the armor to an unusable thickness if they intended to convert the ship back to a battlecruiser?


 * 4. You assert that Akagi and Kaga were "Rebuilt in 1935-38 by stripping off flight deck and removing barbettes. Then building new hangar deck where barbettes once stood. Then adding new wooden flight deck on top." You go on to claim that the increased aircraft capacity came from the barbettes that were allegedly removed.


 * These assertions do not make sense. Please read a reputable book such as "Imperial Japanese Navy Aircraft Carriers 1921-45" by Mark Stille and Tony Bryan or "Aircraft Carriers of the World 1914 to the Present. An Illustrated Encyclopedia" by Roger Chesneau. These books explain that the flight deck and existing hangars were LENGTHENED and EXTENDED over the bow, and the flying off decks were removed. The flight deck was never "stripped off."


 * The lengthened hangars were the reason for increased aircraft capacity after the second conversions, but they were not added in place of battlecruiser barbettes. They were added where there was no structure before. Two barbettes and turrets were removed in the process. But they WERE NOT the battlecruiser barbettes. They were the two 8 inch gun turrets mounted on one of the flying off decks. Look at the JPEGS above. These guns are clearly illustrated. The Washington Naval Treaty specified that carriers could mount 8 inch guns, so the Japanese took advantage of that provision. They did not prove very useful, but the 8 inch guns were retained in casemates even after the second reconstructions.


 * Based on your comments, it appears that you do not understand what barbettes are or where they would have gone. Look at this diagram showing the barbettes in Nagato. [] Do you see how deep they are? In Akagi and Kaga, retaining the original battlecruiser barbettes after the initial reconstruction would have been impossible because the B barbette would have protruded through at least the lower hangar floor and blocked the flying off deck. Flying off decks did not work well for the Japanese or the British, who also used them. But the Japanese were not stupid enough to physically obstruct them.


 * As for A, Q, X, and Y barbettes, they were only designed to extend up to the main deck level, below the floor of the lower hangar. It would have been impossible to "build new hangar deck where barbettes once stood," unless the ships were demolished to the waterline. Your assertion is not only false, it's completely implausible and physically impossible.


 * 5. And the reason for the second reconstructions?  You assert that Akagi and Kaga received "extensive rebuilds to improve aircraft handling capacity because plans to convert them to capital ships were abandoned." Your assertion is patently false. Instead, the multiple flight deck configuration was a failure and that was the reason for the reconstruction. Stille and Bryan write that Akagi's "multi-level flight deck configuration proved impractical."  This Naval War College Review article, available on the Naval Historical Center's website, says "both Japanese carriers sported multiple flight decks when completed. This arrangement proved so unsatisfactory, however, that both had to be redesigned and rebuilt in the mid-1930s with single flight decks." []


 * 6. You state that your version of facts is supported by "Warship Mechanisms Picture Book: Japanese Aircraft Carriers" written by Hasegawa Tôichi, published by Grand Prix, Tokyo, 1997. Other people have told me that this book does not support your claim. See this forum, where I posed the question we are now debating. [] I think you should post your theories there and see what those forum members say. They are extremely knowledgeable and as you can see, they have explained that your assertions are false.

Orpy15 (talk) 21:09, 28 December 2007 (UTC)

Thank you Orpy. Please see forum you cited [] where very experienced and extremely knowledgeable members Dan Kaplan and Rod Dickson say this:


 * Dan Kaplan: "Shibumi-san's answer is very concise, and makes much sense within the context of those times. Especially interesting is the specificity of the two different reconversion schemes. Perhaps it makes more sense for the Wikepedia entry to be modified to say that initially, there were reconversion plans for these ships due to IJN concerns about how effective aircraft carriers would be, but these plans were abandoned by the time the carriers were reconstructed as full deck vessels. We all want to get the information correct but, perhaps the Japanese did place more emphasis on these alternatives then has been known in the West. Something to consider."


 * Rod Dickson: "I have to agee Dan - it does put a different prespective on a fluid period. As far as armament laying about after a conversion - just look at SHINANO's battleship amarment surviving postwar."

Orpy I invite you to modify affected articles to reflect suggestion contained in message by Dan Kaplan: "Perhaps it makes more sense for the Wikepedia entry to be modified to say that initially, there were reconversion plans for these ships due to IJN concerns about how effective aircraft carriers would be, but these plans were abandoned by the time the carriers were reconstructed as full deck vessels." Thank you. Shibumi2 (talk) 18:49, 4 January 2008 (UTC)

I will copy my response to all members of discussion on that message board Orpy. I copy it here for all Wikipedia editors to see.

I will try to answer all questions. I thank everyone for your inquiries.

Dan Kaplan: "Perhaps the reconversion plans were a sort of contingency alternative formaulated when these ships were being converted for the first time."

Yes this is exactly true Dan.

Dan Kaplan: "However, it is quite clear that, as Frido pointed out, serious alterations were required to make them into carriers in the first place. Along with the Treaty requirements, it seems unlikely that the reconversion plans were anything more than a contingency. The costs to reconfigure again, aliong with advances in design, make it so unlikely that it would have actually happened."

Remember environment in which these decisions were made: mid-1920s Japan. Always concerned about invasion fleet approaching Home Islands. This is at central core of Japanese naval strategy since days of Genghis Khan. His invasion fleet was destroyed by typhoon. Otherwise Japan would have been another province in Mongol empire. In 1920s aircraft carrier was believed to be inferior to battleship due to weakness of carrier based aircraft. As their capabilities improved opinion of admirals improved. I agree it was unlikely. But because of belief that battleship was superior admirals created contingency plan.

Tiornu: "I think that it is common to make plans that are not really plans. It is possible that someone suggested the Kaga and Akagi reconversion plans only to please those admirals who doubted aircraft carrier abilities, and no one really meant to change the two ships."

Tiornu please remember in 1920s all Japanese admirals doubted aircraft carrier abilities. Only Billy Mitchell with heavy land based bombers sinking OSTFRIESLAND proved aircraft could sink battleship. Light bombers for carriers were believed impotent against battleship. Like Americans they believed aircraft carrier would serve best as scout to find enemy. Then send wireless message to capital ships which would close in and destroy enemy. This was reason why KAGA and AKAGI had plans for reconversion. HOSHO aircraft plus catapult floatplanes on capital ships and cruisers were believed to be sufficient.

David Dickson: "Coming at it from the other end of the line it has been my understanding that after Midway when the navy was looking around for likely candidates for flight decks the ISEs (and FUSOs) were candidates, but the most preliminary studies to convert them to a kind of cross between AKAGI/KAGA with JUNYO style superstructures indicated you could build keel up UNRYU type ships quicker and easier than the contemplated conversions."

David this is what I always said. UNRYU was Japanese version of ESSEX. It could be quickly mass produced. Too many resources invested in reconstructing existing ships. Better investment would be train more crews and build new ships to expand fleet. But Japanese High Command was reluctant to expand number of ship crews rapidly like Americans did in 1942-1945.

Eugen Pinak: "Both "Akagi" and "Kaga" had 5 turrets - 2 on the bow (A, B) and 3 on the stern (X, Y, Z). Of them B and Z were located on the positions of the elevators, co its barbettes simply had to be removed. I'm also not sure, if batbette of A turret will fit between barbettes of 20-cm turrets. There is another problem (at least in case of "Akagi") - you can't "squeeze" barbette of Y turret between 20-cm gun casemattes. And don't forget about problem with armour (it was simply not enough for capital ship) and fire control directors (you need to build new superstructure from scratch to place them high enough). So, IMHO, one can forget about "quick conversion".

Here is link to profile of AKAGI as first designed.

http://www.globalsecurity.org/military/world/japan/images/akagi-cb.gif

Reading from bow to stern I learned to identify this turret configuration as A-B-X-Y-Z with B and Y turrets being tallest. Not B and Z turrets. It is true that B and Y turrets were not part of emergency rebuild plan (PLAN A). But A-X-Z would give 3x2 main armament configuration similar to REPULSE and RENOWN. Parts for these three turrets with tripod mast and two smokestacks were built and stored in warehouses at shipyards. Observe its simple superstructure with armored bridge and fire control decks. Armored bridge also built and stored in warehouse.

This was not story of sailor. This was story of engineer. My grandfather had detailed blueprints. More extensive rebuild (PLAN B) would have added B and Y turrets with barbettes and improved armor belt. Some 20cm casemates would also be removed but some were planned to stay. This 20cm secondary battery plan was unique to AKAGI and KAGA rebuild plan. No other capital ships anywhere were planned with 20cm secondary battery. This was planned to compensate for reduced main battery (only three twin turrets).

After 1935 contingency plans for rebuild of AKAGI and KAGA as capital ships were abandoned. Components built and stored in warehouses became useless. I do not know what happened to them. Probably scrapped and metal used in building new ships such as YAMATO. Most copies of blueprints for conversion were destroyed.

You mention spacing of 20cm casemates. Remember this was plan for violation of Washington Naval Treaty. Secrecy was essential. I give you example. This is from Wikipedia article about Japanese battleship Yamato. It was designed as 68,000 tons.

"To further confuse the intelligence agencies of other countries, Yamato's main guns were officially named 40.6 cm Special, and civilians were never notified of the true nature of the guns. This worked so well that as late as 1945, the U.S. believed the Yamato had 16 inch (406 mm) guns and a 40,823 tonne displacement, comparable to the Iowas. Funding for the Yamato class was also scattered among various projects so the huge costs would not be immediately noticeable. At the Kure Navy Yard, the construction dock was deepened, the gantry crane capacity was increased to 100 tonnes, and part of the dock was roofed over to prevent observation of the work. Many low-level designers and even senior officers were not informed of the true dimensions of the battleship until after the war. When the ship was launched, there was no commissioning ceremony or fanfare."

As you can see Japanese Navy shipyards were capable of skilled deception. I suggest some details of AKAGI and KAGA conversions in 1920s believed to be fact today might be part of deception that survived as "fact." This may include space between 20cm casemates. Shibumi2 (talk) 18:55, 4 January 2008 (UTC)


 * I am sorry, I don't want to poke my nose into other people's business, but I noticed this discussion and found it interesting. I am very skeptical of the claim that Akagi and Kaga retained their barbettes, but I would like to hear more.  I wanted to point out one inaccuracy in your statements above.  You stated that B and Y turrets were tall, and were not part of the emergency rebuild plan, but A, X, and Z were planned to be restored.  X turret is just as tall as B and Y, so it could not have been retained either; it would have projected into the hangar. TomTheHand (talk) 02:29, 5 January 2008 (UTC)


 * Hello Tom. Your opinions are welcome. I answer your question here. You say X turret has same elevation as Y turret so its barbette would also extend upward into second hangar. But question for B and X turrets was elevator placement not extension into second hangar. Each elevator required "well" for hydraulic cylinders. This required space about 9ft (3m) under elevator when in fully retracted position level with third hangar deck. So there was no space for Y turret barbette.


 * Rebuilds in 1935-38 were very extensive. Same amount of resources could easily have built two more SHOKAKU class aircraft carriers. This would mean eight full sized carriers at Pearl Harbor - four at Coral Sea - maybe six or eight at Midway. Result of war could have been very different.


 * Thank you for your question. I will leave note on your talk page also. Shibumi2 (talk) 22:00, 6 January 2008 (UTC)


 * Why would they place the aft elevator in a position that required removing Y barbette? Why wouldn't they just put it between X and Y, if they wanted to retain barbettes? TomTheHand (talk) 22:50, 10 January 2008 (UTC)