It seems that there are few information about the development of Japanese AP shells and older type shells before the famous Type 91.
I have seen some interesting discussion on that topic but not in English. What's more, I have found some new information and decided to share them, so I start this thread.
The development of Japanese AP shells has been briefly described by several books, such as Japanese Cruisers of the Pacific War and 海軍砲術史(History of Naval Gunnery in English). They all claim that:
The following pic is from a Japanese doc dated 1918.08 (Taisho 7), it shows some different cap design and their description, translated as:
實帽 (Solid Cap) S.C. Fitted on shells bought from British Hadfields in Meiji 44 (1911), .
空帽 (Hollow Cap) H.C. Later improved Hadfields cap.
朱式帽 (Schneider Type Cap) R.S.C. S.S.C. Fitted on shells bought from Schneider in Taisho 2 (1913), there are two types, one round (edge) type, one sharp (edge) type, the cap head is hardened.
三年帽 (3 Year Cap) 3.Y.C. Standard shell cap adopted in Taisho 3 (1914) ... Cap head is hardened.
波社新型帽 (Hadfields New Cap) N.C. Fitted on new type shells bought from British Hadfields for test purpose in Taisho 7 (1918), the cap is similar to our own 3 year cap.
Based on the above doc and other Japanese sources, the so called Type 3 APC might be more accurately referred as 3 Year Cap AP shell as used by some Japanese authors, without a true Type designation. I have seen many late-1910s and early-1920s Japanese plate trial records labelled shells as 3.y.c., but never seen a 3 Year Type or Type 3 designation.
And, the cap of this shell is based on French Schneider hardened cap, while the body might be based on British design.
The following pic from Yuzuru Hiraga Digital Archive is an undated table of different shell designs for what the doc referred as "3 Year Type 14-inch Gun", which is clearly a cover up since the dimension of shells revealing the true 41cm calibre.
Note that the leftmost shell looks very similar to early French capped AP shells, indicating that these shell designs should be completed at a date not far from the adoption of Schneider cap design.
The other 4 drawings show 2 slightly different APC designs and 2 different CPC designs, all using a cap similar to the abovementioned "3 Year Cap", so these should be early design of 41cm 3 Year Cap AP Shells.
I have seen some interesting discussion on that topic but not in English. What's more, I have found some new information and decided to share them, so I start this thread.
The development of Japanese AP shells has been briefly described by several books, such as Japanese Cruisers of the Pacific War and 海軍砲術史(History of Naval Gunnery in English). They all claim that:
However, another Japanese book (海軍装甲技術史, History of Naval Armor Technology in English) describes the history of this early APC shell differently. The description is roughly as follows:Until the mid-1920s the 40-cm and 36-cm. capped armor-piercing (AP) shells of the Imperial Navy were the Type 3 (3 Nen Shiki, third year of Taisho = 1914) developed by the Kure Navy Yard in 1914. These shells were derived from the 36-cm AP shells imported from Great Britain for the battle cruiser Kongo, completed in 1913. Both capped AP and capped common 36-cm shells, adopted on 26 May 1915, were fitted with a Type 3 No.1 base fuze.
The above statement is in good agreement with some files found on Yuzuru Hiraga Digital Archive.In 1912 (Meiji 45), technology of Hadfields was introduced and the production of hollow cap shells began.
However, in 1913 (Taisho 2), Imperial Japanese Navy bought some Schneider APC shells and carrierd out firing trials to compare Schneider design with Hadfields design.
The cap of Schneider shell had its tip hardened to obtain better performance, and the trial result showed at least 10% advantage over Hadfields design which use a mild steel cap at 0° attack. Moreover, when subject to oblique impact, Hadfields shell can not perforate the plate in a condition fit to burst even if the angle of attack is less than 10°.
Due to its better performance, IJN adopted Schneider cap design and manufacture method, but changed cap attachment from French groove ring to British notch pits. The new cap was designated as 3 Year Cap (三年帽, Taisho 3 = 1914).
The following pic is from a Japanese doc dated 1918.08 (Taisho 7), it shows some different cap design and their description, translated as:
實帽 (Solid Cap) S.C. Fitted on shells bought from British Hadfields in Meiji 44 (1911), .
空帽 (Hollow Cap) H.C. Later improved Hadfields cap.
朱式帽 (Schneider Type Cap) R.S.C. S.S.C. Fitted on shells bought from Schneider in Taisho 2 (1913), there are two types, one round (edge) type, one sharp (edge) type, the cap head is hardened.
三年帽 (3 Year Cap) 3.Y.C. Standard shell cap adopted in Taisho 3 (1914) ... Cap head is hardened.
波社新型帽 (Hadfields New Cap) N.C. Fitted on new type shells bought from British Hadfields for test purpose in Taisho 7 (1918), the cap is similar to our own 3 year cap.
Based on the above doc and other Japanese sources, the so called Type 3 APC might be more accurately referred as 3 Year Cap AP shell as used by some Japanese authors, without a true Type designation. I have seen many late-1910s and early-1920s Japanese plate trial records labelled shells as 3.y.c., but never seen a 3 Year Type or Type 3 designation.
And, the cap of this shell is based on French Schneider hardened cap, while the body might be based on British design.
The following pic from Yuzuru Hiraga Digital Archive is an undated table of different shell designs for what the doc referred as "3 Year Type 14-inch Gun", which is clearly a cover up since the dimension of shells revealing the true 41cm calibre.
Note that the leftmost shell looks very similar to early French capped AP shells, indicating that these shell designs should be completed at a date not far from the adoption of Schneider cap design.
The other 4 drawings show 2 slightly different APC designs and 2 different CPC designs, all using a cap similar to the abovementioned "3 Year Cap", so these should be early design of 41cm 3 Year Cap AP Shells.
statistics: Posted by Jean_Bart_1955 — 4:17 PM - Today — Replies 0 — Views 22