John 3rd
Posts: 17178
Joined: 9/8/2005
From: La Salle, Colorado
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Just went through the entire Thread writing notes. I decided to cut-and-paste the Fleet summaries so we have it all in one Posting:
CVs
You forgot Junyo and Hiyo in both calculations for both sides. Technically, Hiryu-class Zuiho and Shoho can and should be available at the start. They will actually occupy shipyards for less combined time, than shadow rebuilds. And they will be laid down instead of them, i.e., four years before the war. And repeat Shokaku carriers, laid down in late 1940 can be completed in winter - early spring of 1943 (construction of Unryu too 2 years, but here it will be slightly slower). That's what I envisioned, and that's the gameplay reason I'm opposed to making Ryujo so big.
What I see, at the opening of hostilities:
Stock:
Akagi (81),Kaga (72), Soryu (63), Hiryu (71), Shokaku (72), Zuikaku (72), Ryujo (48), Zuiho (30), Hosho (20), Taiyo (27) = 556
Mod:
Akagi (81), Atago (64), Soryu (63), Hiryu (71), repeat Hiryu 1 (71), repeat Hiryu 2 (71), Shokaku (72), Zuikaku (72), Ryujo (48), Hosho (20) = 633
Added later in 1942
Stock:
Junyo (53), Hiyo (53), Shoho (30), Ryuho (31), Unyo (27), Chuyo (27) = 221
Mod:
Junyo (53), Hiyo (53) = 106
Total by the end of 1942, assuming no losses:
Stock: 773
Mod: 739
Considering that Taiyo-class escort carriers did not have active airgroups IRL, stock and mod almost break even. In the beginning disparity is greater than I thought, but even 70 planes are hardly impossible to produce, when there are obvious solutions for that (see above).
From gameplay perspective Japan actually falls behind in the number of carrier planes by the end of 1942, but these planes are based on much superior platforms. Japanese carrier fleet will fare much better in 1943 and later.
I'm assuming here that Ryujo in the mod can honestly carry 48 planes.
So, the updated OOB of IJN's capital ships:
BBs
BatDiv1--Nagato, Mutsu, Kaga, Tosa
BatDiv2--Ise, Hyuga, Fuso, Yamashiro (None of them modified past the first modernization, and adding a couple of AAMGs, conversion options present from the start)
BatDiv3--Kongo, Hiei, Haruna, Kirishima
BatDiv4--Available: Owari, Satsuma. In construction: Musashi (7/42), Shinano (4/43). As discussed above.
We have all needed art for the battleships.
CAs/CLs
CruDiv1: (Myoko-Class) Myoko, Nachi, Haguro, Ashigara
CruDiv2: (Takao-Class) Takao, Atago, Maya, Chokai
CruDiv3: (15x155 Mogamis, built to displace 10k standard from the beginning): Mogami, Mikuma, Suzuya, Kumano
CruDiv4: (Old CAs, armed as IRL) Aoba, Kinugasa, Kako, Furutaka
CruDiv5: (12x203mm super-CA class) Available: Niitaka, Iwaki. In construction: Hikari (3/42), Kurama (10/42).
Leaders of torpedo divisions: Yubari, Naka, Sendai, Jintsu, Isuzu. The latter four are slightly modernized.
Training cruisers: Kuma, Tama, Kitakami
To be assigned to carrier divisions as recon/AA defense/command center ships there are four CLAAs in construction: Yahagi (6/42), Agano (12/42), Sakawa (2/44), Oyodo (8/44).
In reconstruction as CLAAs/torpedo cruisers, whatever the player prefers: Nagara, Kitakami, Natori, Yura, Kinu, Abukuma.
Reconstructed as AS: Oi, Kiso
Reconstructed as CM: Tenryu, Tatsuta.
Art needed: for both classes of new cruisers, reconstructed ASs and reconstructed CMs.
The proposed OOB clearly goes past the historical Japanese budget for capital ship construction in the areas of pre-treaty BBs completed according to the modifed Washington treaty (2 extra BBs are completed), and post-treaty cruiser construction (10 ships are replaced with 8 of comparable combined tonnage and with considerably more expensive armament). Hopefully, pre-treaty BBs being well on the way to completion and absence of expensive Mogamis rebuilds and rearming will keep these deviations small enough to be plausible (particularly with the overall better economic situation we're engineering for late thirties).
Comparison with RL:
10 modernized old BBs available + 2 new BBs in construction IRL. 8 modernized old BBs, 2 new BBs, 4 unmodernized old BBs available + 2 new BBs in construction in the mod.
4 small CAs, 14 large CAs available IRL. 4 small CAs, 10 large CAs, 4 large CLs available + 2 large CAs under construction in the mod.
18 old CLs available + 5 CLs under construction IRL. 5 old CLs available + 6 old CLs under reconstruction + 4 CLAAs under construction in the mod.
We see a stronger battleline, little change to A-grade cruisers, and considerable reduction of B-grade cruiser strength before beginning of the war. Arguably that is the logical results of greater battleship tonnage allowed, but still, Japanese light forces are actually weakened. The need for building more large destroyers is pressing.
DDs
So a rough destroyer proposal, modified for new 120/45 Type 90 and 120/55 Type 98 guns.
Modification of old DDs - execute modifications described previously, but 120/45 Type 90 replaces 127/40 Type 89. Otori-class TBs are not built. As not building any new light cruisers frees alot of extra resources, also reconstruct 12 Mutsuki-class DDs shortly before the war, replacing old gun armament with 2x2 120/45 Type 90 (one fore, one aft), 2x2 25/60, 2x1 13.2/76, 18 DCs. Accept speed reduction due to extra weight.
Building of modern DDs until Hatsuharu - as RL (23 Special Type DDs).
6 Hatsuharus - modified as DDAA, with 3x2 120/45 Type 90 in unshielded mounts, 3x3 25/60, 2x1 13.2/76, 2x3 610mm TTs with no reloads, 36 DCs.
10 Shiratsuyus - 3x2 120/45 Type 90 in properly enclosed turrets, 2x2 25/60, 2x4 610mm TTs with reloads, 16 DCs. Size and design as RL.
10 Asashios - main armament is the same as on the previous class, the main differences are turret positioning and powerplant. Hull is smaller compared to RL, allowing to save materials and achieve greater speed (36-37 knots) with the same power.
20 Kageros - slighly bigger than Asashios, main armament is the same, but the number of depth charges on board is increased to 18. The main differences, as IRL, are lighter engine and greater cruise speed. Savings achieved by building smaller ships start to tell here, allowing to build 2 more DDs (and probably even have extra materials and money left for other projects).
37 Yugumos - design of these ships will be adjusted according to preliminary reports on the war in Europe, if not from the start, then during construction. They will be bigger and slower than Kageros (albeit smaller than RL Yugumos) due to extra armament. Moreover, more robust industry, diverting resources from cruiser construction, in addition to their smaller hull and not building extremely expensive Shimakaze, will allow to construct significantly more of them. 3x2 120/45 Type 90, 2x3 25/60, 2x1 13.2/76, 2x4 610mm TTs with reloads, 36 DCs (1 thrower and 2 racks). The number above includes 20 RL Yugumos, 12 in place of 5 light cruisers (not sure if this is not too few, even after funneling some resources into reconstructions) and 2 in place of Shimakaze. 3 more are added due to savings on hull size/streamlining of production. 7 of these are available before the war, then about 10 per year for next three war years.
Total number of 1-st class (i.e., can fire 610mm torpedoes) DDs available at the opening of hostilities: 88 (80 IRL). Total number of DDs with modern DP armament among them: 65 (basically 0 IRL, around 30 ships, if not less, had guns with limited anti-aircraft capabilities).
16 Akizukis - the size of RL Akizukis or slighly smaller, due to carrying heavier guns. Lack of expanded magazines for the fourth turret will allow to install a bigger and more powerful engine. Alternatively, just use the same 52 000 hps engine and accept the modest drop in speed. Initial armament of 3x2 120/55 Type 98, 3x3 25/60, 4x1 13.2/76, 2x4 610mm TTs with reloads, 72 DCs (2 throwers and 2 racks). Available from summer of 1942, and construction is limited by availability of the new guns.
35 (81) Matsus/Tachibanas - a slightly less bare-bones design, reflecting slightly better economical situation of Japan due to various things going better for her before and during war. The design is accepted earlier, due to Escort Command long crying for new ships, designed to be improved versions of reconstructed escort destroyers, and having designs on hand. But construction is slower, as the existing Yugumo design is more suited for realities of the war than the RL one. First ships are available in autumn of 1943. 35 are built until late spring 1945. 46 more are late-1945 and 1946 ships (going RA route and building only Matsus late in the war, if the player chooses to build anything at all), to a total of 81. About 1450 tons of standard dispacement, 2x2 120/45 Type 89, 4x3 + 6x1 25/60, 1x5 610mm TT without reloads, 60 DCs.
Note on armament: a single 25/60 mount is introduced earlier in this alternative, due to earlier demand for a free-swinging flak weapon, capable of quick aiming, but it is still not available until late 1942. 13.2 MGs (also in limited supply...) are installed instead of it on newly constructed/reconstructed DDs, as well as DDAAs.
While I'm at it, how about the following take on the escort forces and subchasers?
Escorts
CD-A Class (16 ships built before the war, 2 in construction). First ships laid down in 1938-39 according to the specifications created by the Escort Command, instead of Shimushu escorts and Ch-4 (and following) large subchasers, using diesel engines of same power (2600 hps) as the latter, but with the requirement of relatively high range and greater seaworthyness, so that these ships will be able to escorting resupply convoys to Mandates in case of a war (convoys from SRA obviously aren't on the table yet...). This, as well as the requirement of heavier armament, so that new ships won't be outgunned by subs, leads to serious increase in size. Their hull resembles a cross between a Ch-13 subschaser and a RL kaibokan. The design is kept simple, by pre-war standards, due to conflict between doctrines and plans developed by Escort Command with limited funding, not allowing to implement them. Armament removed from reconstructed warships is used for same reason. 800 tons of standard displacement, speed closer to 17kts, range 6000 nms, 1x1 120/45 10YT (on the bow), 1x4 13.2/76, 1x1 40mm Vickers, 18 DCs (an increase to 36 is already planned).
This class obviously replaces Ch-4 and Ch-13 large subchasers.
CD-B class (1 built before the war, 15 in construction, available throughout 1941-42). A version which production launched on merchant shipyards in parallel with Standard Type cargo ships in late 1940, as the part of the same program of ensuring the Empire's economical security in case of a war. Plagued by various flaws and delays, caused by excessive attempts to cut costs and builders' lack of experience, as well as struggles for obtaining their cut of budget until the opening of hostilities. Uses an engine comparable to Ch-13 subchasers, which proves underpowered. Results are less than impressive: 730 tons, 14 kts, range 4800 nms, 1x1 120/45 3YT (due to shortage of high-angle guns), 2x1 40mm Vickers, 1x1 76/40, 36 DCs.
CD-C class (80 available starting from autumn of 1942 and until the end of 1944). Ordered immediately after the initial success in the war becomes clear, in place of Etorofu kaibokans and Ch-28 subchasers. Replaces Etorofu, Mikura and Ch-28 classes. Derived from CD-A, as Escort Command cannot resist the lure of a ship with greater overall performance. 850 tons, 20 kts (engine is less powerful than that of Etorofu/Mikura/Ukuru, about 3400 hps, but size is smaller as well), 7000 nms, 1x1 120/45 10YT, 3x2 25/60, 2x1 13.2/76, 72 DCs.
Take note, that the aft 120mm guns aren't installed on any of the proposed escorts. That's due to doctrine, that commands escorts to engage subs by swiftly closing distance, with the intent to conclude attack by ramming. Therefore aft guns are seen as unnecessary for artillery duels with subs, and against air targets extra 25mm MGs are more effective than 120mm DP guns without real fire directors (IRL, not in the game...). If some sort of modern single-mount 76-88 AA gun will be adopted by Navy in this alternative, it can be installed in the aft position later in the war, instead of more 25/60 triples. Besides more ASW/AA weapons, extra space will be used to expand fuel tanks a bit.
CD-D and CD-E (300+ available starting from early 1943 and until the end of the war). Class CD-B finally done right. A rough equivalent in size, engine power, and capabilities to RL Types C and D, including use of turbine engines on CD-E, due to deficit of diesels, but with armament based on CD-C above, although with less AAMGs initially.
I'm postulating parallel production of two escort classes to keep a link with the reality, to a degree. Tactically, fast and more capable CD-C escorts will be intended to be able to support escort destroyers in protecting fast convoys running to the frontline, (or working in dedicated ASW patrols, when these will be adopted), while other escorts will be meant to defend shipping lanes to SRA.
Cha-1 auxilary subchasers (approximately 200 available, beginning from summer of 1942). No difference from the type in the game. Production starts on small shipyards immediately after the beginning of hostilities, to provide protection from coastal convoys and harbor defense.
Pa-1 patrol boats (approximately 300 available, beginning from early 1944). A replacement class for Cha-1 SCs, using the same engine and built on the same shipyards. Bigger and slower, with 2500 nm radius of action, and armament of 4x1 25/60 and 18 DCs.
So, subs in detal.
SS
First, I think if we accept "Terminus doctrine", torpedo armament will evolve in a different direction. Historically the doctrine called for a large-distance surface attacks against the enemy fleet, therefore new oxygen torpedoes had excessively long range (during the war it was reduced to increase the warhead). Now, as our subs still are primarily aiming at enemy warships, big and heavy torpedoes that can deal massive damage by any succesful hit are still in order, but range requirements will be lesser, allowing to either install a larger warhead from the beginning, or to take more of them onboard. With the doctrine stressing the importance of attacking anything that floats, I think the latter is a more logical choice (albeit less effective in game).
On building program: until 1933-34 it goes as IRL, including an experiment with aircraft-carrying boat (I-5) and home waters defense boats (RO-33 and 34). However, IJN doesn't enter its prolonged stage of doubts about the optimal sub type in thirties. Three Junsen 2/3 subs aren't built because the first one proves disappointing from the viewpoint of the new doctrine. Instead KD6A type is expanded by one boat, and KD6B by two. KD6A/B is the first significantly changed type, as more powerful electric motors and stronger hull to increase underwater speed diving depth slightly further than IRL are used, while hps of diesels and top surface speed do not increase as much. The cruise speed these subs can maintain is increased though, as IRL (actually, IRL these subs had a range of 14000 nm, when maintaining the same 10 knot cruise speed as their precedessors, but they were able to cruise at 14 knots, at the expense of decrease in range).
So, overall, 11 KD6A/B subs are built.
Then comes 1937 and the beginning of the Japanese post-treaties sub-building rush. Two types of subs are laid down are constructed during it. Both include changes in construction similar to KD6 above. I.e., advances in engine design are used to improve underwater speed and maneurability or save space for other improvements, rather than supercharging surface speed (which is kept around 20 knots).
First is C1 type (A1 type in this alternative) attack boats, meant to serve as midget carriers. 6 are laid down and completed before the war. As A/B/C boats were developed from Kaidai, rather than Junsen, no problems with designing them here...
Second is KD7 type. IRL that type seems to be a failure, to be honest... I wonder why it carries less fuel and less torpedoes than KD6, without real increases in anything else, and no books on Japanese subs I've read explain this. Speed is, however, higher than that of KD6, despite bigger size and less powerful engines. Can it be a case of someone misreading its stats and the mistake then propagating across various books? Anyway, in the mod, this series should basically repeat modified KD6B, except with all-forward torpedo tubes and diving depth standartized to that of A1.
This class will replace 22 A/B subs and 8 RL KD7 subs laid down before the war. However, this budget also must provide for 2 ARs and 4 new ASs, which will cost about as much as 8 attack subs. The remaining money will be sufficient to fund construction of approximately 32 KD subs (exchanging big subs for medium ones at 2:3 proportion). Hopefully, smaller size and faster construction will enable to complete 2/3rds of this number before the opening of hostilities.
The number of available subs on 7/12/1941 therefore will be:
11 large submarines (5 old patrol subs of J1/J1M class and 6 midget-carrying A1 subs)
47 fleet submarines (of KD3 and latter types)
4 sub minelayers
2 coastal submarines
One thing I'm pondering here is exchanging 2 fleet subs for 2 sub minelayers of a more decent design in mid-30s... Mine warfare definitely should get greater attention if a protracted war is expected.
Amphibious Ships
0)Navy retains the overall control over construction and and maintenance of amphibious ships. They are staffed by IJN personnel and carry Navy's weapon models. Their operational use is regulated by a special Army-Navy agreement.
1)LSDs Shinshu Maru, Akitsu Maru and Nigitsu Maru. IRL Shinshu Maru was supposed to have floatplane tender capabilities, but never carries floatplanes IRL (this ship was owned by the Army, so it is not clear what it was even supposed to operate). Akitsu Maru and Nigitsu Maru had flight decks, but could serve only as aircraft ferries, until upgrades in 1943, which allowed them to operate Ki-76s and autogyros. In the game Shinshu Maru has no aircraft capacity, and the latter two operate floatplanes. Unfortunately, it is not possible to restrict a carrier to using certain types of aircraft. The last two ships confound me somewhat. On the first look fitting them with flight decks seems almost pointless, but Japanese seemingly saw them as valuable.
Anyway, I propose building Shinshu Maru as IRL, and Akitsu/Nigitsu Maru as its direct successors, with actual capability to use floatplanes (as IJN actually owns these). Maybe development of float fighters is given somewhat higher priority to hopefully give this amphibious force some teeth. Kumano Maru is reconstructed along the same lines later in thw war.
2)Historical ships Mayasan, Tamatsu, Kibitsu, Hyuga, Settsu and Tokitsu Marus are added to construction queue as LSDs (we already added some of them in RA). Another RL landing ship apparently missing from stock, Takatsu Maru is added as an AP or APA.
3)Let's build a series of dedicated Type 0 APDs, capable of deploying landing barges, both to serve as a vanguard of ambitious operations, and to supply island garrizons if control of seas around them is temporarily ceded during a protracted campaign. Build 10-12 of them, using a simplified Shiratsuyu-class destroyer hull and an engine half as powerful. Half should be available before the opening of hostilities. The experience gained should also allow to start production of Type 1 APDs much sooner (mid-1943).
4)I thought about adding a pair of special-project 11 000-ton LSDs as a part of pre-war auxilary construction program, mentioned in the submarine proposal above. But I'm going considerably past the RL budget here. In fact, we do that with #3 above. And #3 is more important. So, while there are provisions for greater Japanese economical capabilities in this alternative, I'm reluctant about this.
Mine Warfare Ships
1)Okinoshima and Tsugaru are replaced by converted Tenryu and Tatsuta as fast minelayers.
2)I noticed that four-ship Hatsushima class of cable/net/minelayers is absent from the base DaBabes scenario. They weren't that useful for mine warfare, but let's include them.
3)W-classes minesweepers are not completely repurposed as escorts. Instead remove both their aft and amidships 120/45 guns, around 1943, replacing them with Y-guns, but keep sweeps.
EDIT: IRL these ships were repurposed as escorts, because the Allies did not put much effort into the mine warfare until the aerial mining campaign against Home Islands in 1945. In the game Allied players usually are much more active with offensive or defensive mining, or both. I personally forbit mid-war upgrades to W-clases DMSs, which turn them to Es.
As a side note, I don't know if it is possible to simulate ineffectiveness of traditional minesweeping methods against late-war US mines. Does a mine's Accuracy stat impacts its ability to hit a sweeping ship first?
4)No late mid-1943 give a serious thought to simplifying and streamlining mine warfare vessel production, bringing it in line with measures already taken to make destroyers and so on more affordable. Start laying down the equivalent of maximally simplified Kamishima-class CMs in autumn of 1943 (available in late spring of 1944) and use the same basic hull to construct AMs as well. Stop construction of W-19 class DMS past W-30, and instead build these cheap AMs in numbers.
EDIT: As Type 4 and Type 93 mines are not interchangeable, we need two versions of the same type, carrying one or another.
5)I also really think that a small production run of fast DMs, similar in dimensions and propulsion to the above-described Type 0 APDs would be really nice, but again, this is just adding ships from nowhere, particularly if done before the war. And I don't think IJN can afford to cut the destroyer production for this. Maybe we instead can take a half-dozen of old Momi/Wakatake destroyers, and instead of conversion into P.51 escorts, as described in the destroyer proposal, expand their mine load (they could carry mines in the initial design), but I'm not sure their speed will be enough to operate on the frontline, instead of escorting ships on inner communications.
Torpedo Boats
Built in greater numbers, instead of midgets, as in RA. One thing we overlooked there was Shinyo boats - as the naval combat model does not include ramming, I propose modelling them as low-accuracy CD guns, rather than ships. And their units as CD units, accordingly.
Cargo Ships
The first program of standard-type merchants construction is started in autumn of 1940 by Transport Ministry, and first it honestly doubles as the state-sponsored program of ensuring independence of Japan from foreign shipping, in case of breakdown of relations with the westen powers. Second War Standard Program is adopted in November of 1941, immediately after the decision to fight the war is made, thanks to the general assumption of a prolonged war. As the result, there are more cargo ships in the queue.
Also, AA armament of the most valuable large cargo ships and tankers is increased in 1943-44, with ineffective 13.2 MGs gradually replaced by 25/60 singles.
< Message edited by John 3rd -- 10/24/2011 5:34:04 PM >
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RE: IJN Troops - 
Dutch
Surely the Japanese can find 50 more planes and crews in 1944. The only real factor would be shipyard space, but perhaps in starting the Unryus earlier the repeat builds would be even more efficient? The decision could also be justified by the fact that the Taiho, while an excellent and tough ship, is less useful when horribly outnumbered (If Japanese planners consider American industrial potential, they might realize that sooner or later their fleet will be outnumbered and even the Taiho might take critical hits and sink anyways).
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