Whilst thinking about optimizing the Japanese Navy, which involved mostly building aircraft carriers, destroyers and escort vessels over 1937-41, I started to imagine an optimized rebuilding of Nagato and Mutsu over 1936-7 paid for out of the budget for the 1935-6 and 1936-7 financial years. If a very costly rebuilding was undertaken, Japan might gain some diplomatic advantages over 1937-41 and an expensive rebuilding of two battleships would make it less likely that anyone would guess that the concealed ships named after ancient provinces being built over 1937-41 were aircraft carriers. Delaying the rebuilding by a year and a half has a few advantages including slightly better machinery, possibly using 25 kg/cm2 rather than 22 kg/cm2 boilers, more time for hydrodynamic studies and making it easier to reveal the details to foreign naval attachées ("Honestly, until we reattached the belt in January the displacement hadn't gone up by even 3,000 tons always assuming that one could calculate a displacement when there were holes in the hull"). The IJN might even send Mutsu in place of Ashigara to the May 1937 Coronation Review if she was ready in time.
Historically Japan added large bulges and used the extra displacement to support additional armour and some anti-aircraft guns. There are some obvious criticisms of the rebuilt ships vulnerability to battle damage. The most obvious is that Nagato's machinery was still only protected against WW1 pre-Greenboy shells and even then only at close range. The second is that the dive bomber attacks on Ise and Hyuga suggested that bomb hits on the bulges could cause serious flooding (for example, bombs 6 and 11 on Ise https://www.fischer-tropsch.org/primary ... S-06-1.pdf) and that bombs exploding on the armour shelf could blow the main belt outwards. The report also suggests that the design of roofs of the main armament turrets of Ise and Hyuga were flawed due to the sighting hoods, which was addressed in the rebuilding of Nagato and Mutsu. We might also mention the contrast between the Japanese ships with four twin five inch anti-aircraft turrets after rebuilding and the rebuilt HMS Renown with ten twin 4.5 inch anti-aircraft turrets. However, Nagato's rebuilders did ensure that the fate of HMS Hood, a near contemporary of Nagato with similar strength of armour, could not happen to their ship.
As I know nothing about naval architecture, very little about naval history and cannot read Japanese, naturally I believed after looking at a few images on the internet that I could do better than the IJN. However, it seems that it is rather more difficult than I had initially assumed to plan a rebuild to give 25 knot ships that will not be quickly defeated by more modern battleships. Although Nagato's full load displacement in 1944, 46,690 tonnes or 45,950 long tons, is similar to that of later battleships (45,519 tonnes for North Carolina; 47,728 tonnes for Richelieu; 45,236 tonnes for Littorio), the constrains of modifying an old design make it impossible to match those ship's qualities. The constraints obviously become more severe as we retain more of the existing 1920 design to save on cost. Thus I am reduced to asking for assistance from you experts.
Historically Japan added large bulges and used the extra displacement to support additional armour and some anti-aircraft guns. There are some obvious criticisms of the rebuilt ships vulnerability to battle damage. The most obvious is that Nagato's machinery was still only protected against WW1 pre-Greenboy shells and even then only at close range. The second is that the dive bomber attacks on Ise and Hyuga suggested that bomb hits on the bulges could cause serious flooding (for example, bombs 6 and 11 on Ise https://www.fischer-tropsch.org/primary ... S-06-1.pdf) and that bombs exploding on the armour shelf could blow the main belt outwards. The report also suggests that the design of roofs of the main armament turrets of Ise and Hyuga were flawed due to the sighting hoods, which was addressed in the rebuilding of Nagato and Mutsu. We might also mention the contrast between the Japanese ships with four twin five inch anti-aircraft turrets after rebuilding and the rebuilt HMS Renown with ten twin 4.5 inch anti-aircraft turrets. However, Nagato's rebuilders did ensure that the fate of HMS Hood, a near contemporary of Nagato with similar strength of armour, could not happen to their ship.
As I know nothing about naval architecture, very little about naval history and cannot read Japanese, naturally I believed after looking at a few images on the internet that I could do better than the IJN. However, it seems that it is rather more difficult than I had initially assumed to plan a rebuild to give 25 knot ships that will not be quickly defeated by more modern battleships. Although Nagato's full load displacement in 1944, 46,690 tonnes or 45,950 long tons, is similar to that of later battleships (45,519 tonnes for North Carolina; 47,728 tonnes for Richelieu; 45,236 tonnes for Littorio), the constrains of modifying an old design make it impossible to match those ship's qualities. The constraints obviously become more severe as we retain more of the existing 1920 design to save on cost. Thus I am reduced to asking for assistance from you experts.
statistics: Posted by Ralphseymour — 8:19 PM - 1 day ago — Replies 4 — Views 117