Still nobody to comment ? ...
Anyway, I'm still not tired of posting
2) Geographic deployment and analysis by classes
I have a grand total of 3290 month.DD for the IJN during the war. Among those, 597 were months of refit/repair.
This leaves 2693 month.DD for the IJN to allocate to all its tasks and areas.
Below is a chart of the geogrpahic deployment by classes
Under each geographic column header are both the total number of month.DD spent in this area over the war and the percentage it represents for this class.
For example : the ships of the Kamikaze class spent 35 months in the North Pacific, which represent 15% of the 239 available months for the Kamikaze class.
The unavailability is computed as U/(U+avail) : for the Mutsuki class : 15% = 39/(39+216). Note that the 30% unavailability for the Minekaze class is artificially high and comes from the fact that two ships very put in the reserve for training/target practice very early -- and they are labelled as U in my database.
- IJN_DD_stats_class.jpg (76.85 KiB) Viewed 2644 times
So the main workhorses of the fleet were (not surprisingly) the Kageros and Fubukis, with Yugumos & Mutsuki as distant followers. (I do not take Minekaze and Kamikaze into account here, as they were old DDs, outdated for fleet action).
What appears regarding the geographic deployment is that the South Pacific was the first area where IJN deployed its DDs, with the Home Waters as close second.
"East Indies", "Central Pacific", "Philippines" and "North Pacific" are secondary nonnegligible areas.
Indian Ocean, China and "Viet-Nam" are clearly backwaters.
It's however interesting to note that the classes which around half of the weight of the Home Waters investment are either the late war Matsus, commissionned when there were no other waters any more in the empire, and the old Minekaze, relatively unfit for first line duty.
This should lead us to conclude that the single main area of effort for the IJN DDs was the South Pacific. Actually, it was the focal point of no less than 6 classes out of 12 (I do not count the singl Shimakaze as a 13th class for statistical purposes).
Another relatively surprisingly fact are the 283 month.DDs spent in the North Pacific. It seems like a real overinvestment in meaningless backwaters, and that some of these efforts could have yield greater rewards elsewhere.
However, these are agregate data over the whole war and do not show the evolution of these deployments along the course of the war.
3) Geographic deployment : a 'dynamic' approach
Below is a chart of the number of DDs per location on a monthly basis.
The 'backwaters' (IO, VN & CH) are not shown so as not to overload the chart.
[chart DD_line_area here]
- IJN_DD_line_areas.jpg (38.66 KiB) Viewed 2639 times
So we do not have the information by ship classes, but we now have a pseudo-dynamic view of the succession of areas of effort of the IJN.
We retrieve the well-known sequence of the events of the beginning of the war : conquest of the Philippines (Light blue initial peak) & Central Pacific in Dec 41, immediately followed by an effort in the East Indies (purple peak). Then come operations AL & MI (yellow peak) ... followed by the main effort in the south.
Some other interesting patterns :
* The purple-yellow-green sequence of May-june-July 44 is actually mainly the same fleet -- the one which fought the Marianas Turkey Shoot, showing the concentration in forward base, move towards mariannas & retreat.
* The absolutely massive reaction to the Guadalcanal landings in august 42, with 45 ships transfered in less than one month. IJN staff is often criticized because it did not recognize it as the Decisive battle. However we can see here that the threat was not overlooked, and that the assets, at least regarding DDs, were not sent piecemeal.
* It's only the Hailstone operation that put an end to the presence of the IJN DDs in the South Pacific.
* the Green tail is of relatively small meaning, owing to the lack of fuel. Many of those ships were more floating AA batteries than DDs.
Overall, what is impressive here is the concentrated use of the IJN DDs in one area for a short period (well, it lasted longer in the Solomons, but not for a lack of will from IJN staff).
(note that the chart is not normalized, so even if the Philippine peak of 44 is lower than the Philippine peak of Dec 41, it represent a far higher
proportional investment).
Actually, we can also see it the other way : IJN did not have enough assets to do all its jobs, and was compelled to strike short-term concentrated blows -- leaving the rest of the Empire relatively lightly protected.
More to follow ....
