Anyone interested in some intellectual exercise?

The best plan (IMO) would be for the IJN to commission some tests, with various types of aircraft in the ASW role before you commit to any project. Put some Japanese subs out and see if the aircraft can find them, and make a successful attack (with dummy bombs obviously)

This brings up a good point - is it possible in WITP to conduct exercises? Test theories? I understand that training time will increase an individual unit's effectiveness, but we can we bring units together? Like say rehearsing an amphibious landing? Will exercises enhance their ability to operate as a group? Can we try out tactics we haven't used previously and get feedback on their effectiveness? Or do we have learn "on the job"?

 

My impression is that it wasn't the CVE's alone that gave them a significant impact in the Atlantic. It was a combination of them, radar equiped aircraft (both carrier and land based) and Huff-Duff. Again my impression is that you didn't see a CVE without a decent escort as well. I wonder if the fuel consumption of a hunter killer group is available somewhere....

 

And Ultra - unfortunately a lot of the history written before Ultra was/could be revealed gives the impression that hunter-killer groups searching the ocean was a valid tactic, when most of the time they had at least an approximate idea where to look.

The Battle of the Atlantic was basically won without CVEs, few if any of which operated on the convoy routes before the turning of the tide in "Black May" 1943. The British actually employed their first CVEs in support of amphibious operations - Avenger, Biter, and Dasher in Torch and Attacker, Pursuer, Fencer and Searcher at Salerno. The first American CVEs in action were the four Sangamons also in Torch, three of which then promptly deployed to the Pacific. The decisive battles were fought and won by the convoy escorts and the support groups which, rather than hunter-killing all over the ocean, went where they could find submarines - to the convoys.

 

One thing on the carriers, they are only good during the day. One thing that I do in WITP is to use my PB is HK groups on key areas. I have success with them, Im not sure if that is just a game feature or would be successful. One thing to consider is that float planes and such are good for sweeping an immediate area, but the long range ones are needed for early warning. Im not sure how much air time a float plane or DB/TB would have as compared to a large spotter.

 

One thing that I do in WITP is to use my PB is HK groups on key areas.

Could you expand on that a bit?

I'm also interested in the operation of seaplane tenders you've mentioned. As I understand it, their usual mode of operation was as a mobile base, to set up in some sheltered bay etc. where their aircraft could cover the surrounding area (that's also why I'm skeptical of the need for high speed). Have you been able to use them effectively in support of convoys or merchant shipping?

 

Good post Carronade.
It might be best to try to stick to that terminology for MAC.

Fair enough, but you should be able to stick to what information they had at the time, and come up with some reasonable strategies.

A couple of questions:
1.) As mentioned earlier, did Japan have any dedicated ASW aircraft squadrons?
2.) Were they training ASW flotillas?

That would be the first most obvious solution, the British did fairly well in ASW because they had been planning & training their squadrons & flotillas for years and had invaluable real-war time to build up a large pool of trained staff.
The US was blindsided because they had few ships or aircraft trained when war broke out.

What Japan might best do is to start excercises to train crews how to find & attack subs.

Have you discussed building frigates or sloops instead of destroyers?

Although what would be the purpose of converting MACs? If the old biplanes are not able to provide much effective ASW (which we now know that they couldn't do much) you have a ship which can't operate attck aircraft (Kate or Val) and can't provide air defence because it's too small/slow to operate the Zero
With limited hulls & shipyard time it would probably be best to concentrate on CVEs of the Kaiyo type (550', 23 knots, 24 aircraft) which can still be used for a variety of missions.

 

Good point.
One other thing that I would mention, the Japanese started the war with just barely enough shipping and soon ran short.
However, they didn't run convoys, so if you choose to do that you will lose 30% - 40% of your capacity. Do you really want to pull another dozen or so ships out of service to convert them to MACs that might not even be useful?

Another good post.
Unfortunately for Japan, one of the best tools for ASW was the ASV airborne search radar which they didn't have. The mk. II was in use from the beginning of 1941 on Coastal Command bombers. However it couldn't be fitted on a Swordfish until the mk. XI, which gave a dramatic rise in the number of U-boats attacked from Swordfish.

A huge factor in "Black May" was the introoduction of the ASV mk III on Coastal Command bombers in Mar 1943.

From U-boat.net

British ASV Radars - Technical pages - Fighting the U-boats - uboat.net

 

What follows is obviously MO and to be taken as that only.

One of the things I haven't seen yet is the timing on how the various changes will work. For instance if said change in leadership happened and one of the new council had a new strategic concept that was brilliant that doesn't mean it would be adopted immediatly or at all. I can imagine a number of processes for adopting it one of which might be as follows:

1. Develop a paper describing the concept (hours to days).
2. The council meets and discusses it. (How often are council meetings).
2.a. If it's not obviously brilliant to all it's debated perhaps for several meetings.
3. It's staffed. i.e. subordinates gather all the data and plan out just how to implement it. (days to weeks)
4. The council approves implementation.

There are a number of issues that can slow it down even more.
1) Resources. Are they available and when.
2) By in. Scrapping Shinano isn't going to be popular with the battleship proponents. This is especially important in Japan because if a mid level officer thinks it is damaging to the Japan or the IJN he may take it into his head to assassinate the proponents.
3) Cultural resistence. Again this can be critical and not necessarily obvious. For example the Yamato was suppose to have had just enough oil to fight a battle or two and reach Okinawa for her final mission. However from what I've read the fueling crew didn't think it proper to send her out without enough fuel to return so she actually had more on board. The Japanese approach to damage control was likely influenced by cultural factors as well. Japanese tended to specialize thus damage control specialist rather than everyone practicing it. The allocation of air crews to ships rather than viewing the squadrons as independent may fit in this catagory as well.

The time lines for adopting your proposals could have considerable mutual impacts. For instance if you decide to scrap Shiano her work crews become available for use elsewhere almost immediatly (except for those necessary to scrap her). Her slip isn't going to be availabe right away though and her scrap will in some cases be immediatly available and in some over time. An analsys of where the choke points are in Japanese industry and where the critical paths are for various systems would be very useful.

I would suggest that an estimate of what resources are required and what freed up (if any) along with how much resistence is likely to be generated be considered/reported along with your ideas.

Another factor that you have discussed recently is if and how to use a historical information. I'm not sure that a position has been established on this but it might be a good idea. In many cases it's likely to effect the time estimates I mentioned above. If the idea stands on it's own then I don't see much of a problem. An example might be the mortars mounted on gunboats although in this case one can point to historical examples (ACW mortar boats for instance). Where the idea combines multiple post departure concepts it becomes questionable. An example here is probably the ASW carriers where to be truly effective radar, intercept, intell, and/or experiance are necesary to be really effective.

 

I assigned SP tenders to north Borneo, Cam Rahn bay and such to provide air coverage. I am not impressed with WITP and the mechanics of subs in the game since I am not suffering heavy losses as Japan and the game tends to assign subs to out of the way places like Nome if on computer control for the Americans. For the PB's I a have groups of 4 ships with similar endurance and give them patrol areas based on a port especailly on the approaches to Japan. I did suffer heavy losses as America at the start of the game from subs.

 

I'll answer Carronade. First, seaplane tenders are used exactly as they were historically, to provide support for seaplanes. You can set them up in a coastal location and use them to support seaplane operations without the need for an airfield.
As for ASW operations, you have the option to choose ASW as a mission and then give them a destination and they will patrol for subs to that spot, then depending upon the ASW TF's orders they will remain on station or return to their assigned port. I normally issue "patrol around orders", in which case the ASW TF will partol around that particular area, in a search pattern, until they need to return for fuel or you order them to stop. You can also specify a reaction distance, in which case the TF will react to sightings or contacts up to that range from their specified patrol area. This is where aircraft are helpful. Say you set your ASW TF to patrol an area SSW of Island "X" and set the ASW TF to react up to "Y" distance. When the aircraft set to ASW search spots a submarine (or even a periscope or shadow in the water) it will attack the contact if it can, and radio in a contact report. If set to react the ASW TF will move to the contact area and search for the submarine and attack if detected. Detection and effectiveness of the attacks depends upon the physical properties of the ships in the TF, the experience of the crew(s) and the tactical ability of the ships captain and TF commander. Certain ships within the TF will perform better than others because of the captains and crews. It has been my experience that you get the best results within the game if you use actual tactics. Also, the more tactical you think, instead of just giving orders, the better your results. For instance, you can give a squadron an order to search for submarines and it will search a 360 degree arc. I look at the most likely avenues of approach and concentrate the majority of my efforts there, you are able to set your search in 10 degree arcs, and can set search range and aircraft altitude.

 

Freebird:

While historically the IJN did not carefully consider trade protection or ASW warfare, in part because they were considering a short war, we are attempting what's called a counterfactual. It's often been asserted that this or that decision led to Japan's eventual loss, or at least hastened their defeat. Well, we're trying to test that. So we're not going to attack Pearl Harbor preemptively and we're carefully debating what else we might do differently. We're certainly not going to do everything differently, but if we do nothing differently then we know how the war goes. There's really no point fun that, is there? Additionally, even if it didn't work, the RN certainly TRIED to counter KM submarines with air assets from the very beginning of the war. (And lost one carrier and nearly a second for their trouble.) We KNOW that submarines can be a threat to trade. We know the U.S. has more than a few of the darned things. We know Germany has used them before to good effect and are presently using them again. We're debating using them ourselves, for crying out loud. While they haven't brought England to it's knees they've certainly been trouble. We're even more vulnerable to the things, since the U.S. isn't making their merchant fleet available to us.

I believe a majority of our council strongly favors taking the U.S. submarine threat to our commerce quite seriously. We are attacking this threat in several ways:

First, we are attempting to delay war with the United States until after we have secured our primary objectives. The additional time will allow us both to build new assets and to implement new strategies. We're well aware that this will not be an immediate or even a quick change, but no time in the future will be any more auspicious to make changes than the present. I believe our Prime Minister is quite right. We change now.

Second: We fully intend to use our land based assets to scout for U.S. submarines. The H6K and H8K as it becomes available are great scouting assets should serve us well. I was very much under the impression we have aerial depth charges. If we don't, we VERY soon will.

Third, we aim to put aircraft in our convoys. The advantage range gives land based aircraft is this: they can be where the subs are. Subs will come to our convoys. Guaranteed. If we have a few aircraft in those convoys it won't matter that their range is less. Further, these are IJN biplanes we're discussing, not swordfish. They have a radius of action of 400 miles or more. The IJ Army began developing an autogyro, the Ka-1, for ASW work in mid 1941. The IJN began developing a dedicated ASW bomber in 1942. IJA planned to use Akitsu Maru from the outset as a coastal ASW platform with the Ka-1 flying from her decks. Fixed wing aircraft weren't coming back, but an autogyro would need much less runway. Anyway, the point is this: even historically, Japan was considering aerial ASW operations. They didn't do anything on scale, but we aim to change that.

You assert that we have demonstrated that older biplanes will not be useful ASW assets. How have we demonstrated this? The RN had little luck with them in the early war without airborne radar, but there are some significant differences: the RN was operating principally in the Atlantic, the Fleet Air Arm was primarily equipped with aircraft with woefully short ranges and often poor visibility across the nose, the RN had few aircraft carriers and was unwilling to risk them in ASW warfare. The Atlantic is murkier than the equatorial and South Pacific where we expect to operate. Clear Pacific waters will make it more difficult for a submarine to hide from aircraft. The aircraft that we propose to use have better downward visibility than most RN types beyond the short legged Swordfish. We propose to use merchant ships with a makeshift flight deck. (Thus the term MAC, which I will persist in using to describe these since I'm suggesting using them and not full conversions.) Since it's fundamentally a merchant ship, there's no additional risk. There is no reason not to operate them with a convoy.

Also, Japan's merchant fleet was unusually modern and fast at the outset of WWII. In the fall of 1941 we have about a dozen or so civilian tankers of about 500' with speeds of over 19 knots that we have requisitioned for fleet oilers. I don't have hard numbers yet on ships remaining in civilian service, but I should be able to provide those in a week or two. (When an intelligence report on civilian shipping both friendly and enemy should arrive.) We also have passenger ships of similar specifications that could serve. And slower smaller ships might well suffice with older lighter biplanes. We don't NEED and cannot afford to use frontline aircraft for this duty since we anticipate no aerial threat so far behind our own lines. (Once we have secured the Malay barrier and neutralized the Philippines if necessary.)

Lastly, we very much intend to use sloops, subchasers, and whatever other overglorified fishing boats we can tie depth charges to for our ASW requirements. We've been discussing classes of Kaibokan that could be developed quickly and built cheaply. We have no intention of using airborne assets alone to combat submarines. It would be patently absurd. At present aircraft have no sonar capabilities. Aerial observation and attacks are useful, but should not be the limit of our ASW capability or even necessarily its principal thrust.

You question our skill in operating from small carriers or using converted tankers. First, Ryujo was a testbed for small carrier operations. her flightdeck is only 512 feet long. It was decided that this was too small for effective fleet use, but it should be more than fine for what we propose. We've been operating Hosho (7,500 tons, 552 feet) since 1922 and Ryujo (about 14,000 tons) since 1933. Both have shorter flight decks even than HMS Argus. Both are effectively smaller than any other carrier operated by any other power before 1941. Our pilots have operated from them extensively and in combat. We know how to fly from small carriers.

You contend that Taiyo has no arresting gear. If you carefully examine this photograph of Chuyo, you will see one distinctive element of Japanese carriers that I waggishly call the "flap." These are small platforms that extend to either side at the after end of the flight deck. They serve only one purpose: to make the after end of the flight deck more visible for landing operations. In this case you can see it in front of the crane and just above the trusses supporting the rear end of the flight deck. If there were no arresting gear, there is no need for these flaps. While it has been suggested that Taiyo and her sisters didn't have arresting gear, such a lack would be quite remarkable. Japanese carriers have arresting gear. Why wouldn't Taiyo? Akitsu Maru has no need as IJA aircraft are not designed to land on a carrier even if the carrier had arresting gear, thus it's at least believable that she might not. (Why pay for something you cannot and will not use?) Such a lack in Taiyo defies convention, and while photographic evidence appears a little scant Okham's razor puts the impetus of proof on the less likely proposition. Prove to me she doesn't have it, otherwise I'm safely assuming that she does. Even if she doesn't the point is rather moot since we clearly have the technology.

You have asserted that we should not use MACs because we didn't think of them. I ask why not? They're not that much of a stretch. We have ships large enough and fast enough. We know how to build carriers. We know how to convert merchant ships to carriers. We have even begun a minimal conversion that leaves the ship largely intact below a light flight deck. What makes this something we can't do? I respectfully ask the Prime Minister and other members of the council if we might consider the question of whether we CAN build MACs closed in the affirmative.

Whether we SHOULD is perhaps another question, but it seems inexpensive and at least prudent to be prepared for a threat we see coming. This is certainly something we should test and work to develop, but we can do that. There's no time like the present.

 

This subject has come up in a number of posts recently and I can't address each instance individually, so I'll try to give my opinion here. We are trying and I feel, succeeding in keeping the decisions made within the exercise from being dictated by hindsight. It can not be totally eliminated because we are human, it has been my experience that many things considered contemporary ideas actually started as concepts years before they were implemented. I see it every month when I get my Marine Corps Gazette where officers discuss force structure, weapons, tactics, operational strategies, etc. for what they see as the requirements of the service ten and twenty years down the road. Japan's military officers would have been no different, they were innovative. In 1914 they conducted the world's first Naval launched air raids, the Hosho was the first commissioned warship designed and built as an aircraft carrier. Their decision to carry our a naval air attack on Pearl Harbor, their excellent intelligence work in support of the operation, and their innovative adaptation of weapons in order to carry off the attack, demonstrates their understanding, appreciation of, and adaptability in the use of air power. The Pearl Harbor attack was something they observed from the 1933 exercise involving the Lexington and Saratoga, filed away and used nine years later. The concept was out there. I would further submit that if the effectiveness of naval air power was appreciated, the need for defensive measures to counter this threat was also understood. Hence the justification for all the discussion on AA defenses. Few of the apparent military breakthroughs occur in a vacuum, when they develop into a full blown innovation it is usually because it has been observed and used before and then it is adopted and refined. Germany didn't pioneer close air support, German officer observers saw US Marines experimenting with it in the carribean in the early 1930's and took the idea home and developed it. The US Marines saw ramps on Japanese landing barges in China and brought the concept home and added it to Higgins' Eureka boat to develop the war winning LCVP. Germany didn't develop the doctrine and tactics they used to defeat Poland and France out of thin air. They were a combination of their WWI experiences and incorporated the theories of British Officers J.F.C. Fuller and Liddell Hart, further refined by the German military.

It is documented that some Japanese Naval officers worried about a US submarine campaign. Japan had experience in anti-submarine operations having conducted, with the British, those type operations in the Med during WWI. They built and used submarines aggressively. It is no stretch to think that Japanese submarine officers knew the strengths and weaknesses involved in the tactical employment of submarines and that these were discussed within the naval community. Japan was also well aware of the effectiveness that the German submarine campaign was having in the Atlantic, both from news reports and from Germany herself. IMO, where they got off track was because segments of the military convinced the political leaders that it was possible to fight a short war with the US, in this case the offensive use of submarines against warships makes sense. Had they planned on a long war, their operational use of their assets would in all likelyhood have been different. It is also obvious from looking at a map that if the Japanese succeeded in their initial war plans, the US would have few military options but to strike back with submarines. The short war concept was not taken as Holy writ within the Japanese military either, one of the most prominent voices to the contrary was Yamamoto himself. The Japanese military was dominated by the Imperial Army China element, they also dominated the politics. One of the reasons for promoting Tojo to Prime Minister was because he was popular within the Army and the radical China element, in spite of the fact that he was against initiating war with the US. In our timeline, this element has attempted a coup, but over reached by deciding to target the Divine Emperor with kidnapping. (This actually was attempted late in the war when they feared he would support surrender) If this had occurred and failed the Army's political power would have for a time been diminished. It is during this period that we as the Council would take the reins and for a time, depending upon our success, alternate points of view that had previously been quashed would be able to be voiced.

Japan also was very prone to copy the weapons systems and equipment of other nations, they did it all the time. They were also very receptive to adopting unusual weapon systems. They imported an autogyro in 1939 and intended to use it for artillery spotting and ASW work. Some of the advanced subjects we have discussed that would be based upon wartime experience are things that were actually attempted later in the war, the reason behind this is that I have to input the data into the game editor so that we have that option down the road. The Zero is a perfect example. It eventually had all the improvements that I have suggested, the reason they were not incorporated in the earlier versions is because the added weight would effect performance. The improvements had to wait for the development of higher performance engines. Within the game we will have to devote resources and infrastructure towards R&D in order to develop the more powerful engine. There is no set date or certainty that the research will pay off. When we get it I'd like to have the fighter built with the improvements so I need to enter the data now so we have the option, though we may never be able to build it. The suggestion for designing aircraft to take engines from multiple manufacturers to insure supply and to protect against developmental problems also has basis in fact. The Zero was originally designed to use Mitsubishi Zuisei-13 engine, the Nakijima Sakae-12 had better performance so the design was modified to take that engine and that is how it entered production. So if we discuss designing the B6N to take either the Mitsubishi or Nakijima engine, and the Nakijima engine encounters developmental problems as it did historically, we can still produce the aircraft instead of having it delayed. This decision while not historical would not be outside the bounds of probability, I would however need to enter the data to have the plane use the other engine, in case we make that decision, even if it is something we will not encounter until sometime down the road.
In the end, the game will prove the validity of many of our decisions. I have been tempted a number of times to run some of the decisions with the modified data to see if they prove out, but I have resisted because that would give us an unfair advantage in our decision making. We need to have to deal with the consequences of our decisions, many times unforseen, in order to get the most out of this.

The CVE/MAC for ASW debate is another good example. There are elements within the council that are convinced that it is a concept we need to explore. I think we can accomplish most of it with land based air. Some think our proper course is to convert merchant/tanker hulls to meet the perceived need, others think it will hurt our logistical effort. This is exactly the type of give and take I was wanting when I started the thread. We all have different visions as to the proper course to take, we will have to compromise. In this area I am not so convinced of the correctness of my position that I'm willing to expend political capital on opposing what appears to be the majority opinion. What would happen in real life is that I would barter my vote to support a limited number of these ships being built to test the theory and ask that if I throw my support behind the decision that whoever I'm bartering with support something I feel strongly about. Right now we're still discussing theory, strategic vision and doctrine, when it comes to the actual implementation and voting I think many of the concerns that have been raised as to what we're discussing will become irrelevant. At that point we will have to make hard decisions and deal with the reality of compromise that is necessary in human interactions.

 

Although what would be the purpose of converting MACs? If the old biplanes are not able to provide much effective ASW (which we now know that they couldn't do much) you have a ship which can't operate attck aircraft (Kate or Val) and can't provide air defence because it's too small/slow to operate the Zero

Again, we're talking about merchant ships in say the South China Sea, hundreds of miles from anything we need Kates, Vals, or Zeros to engage. Any aircraft patrolling around a convoy can deny subs the surface throughout daylight hours and provide warning to the convoy, not to mention the opportunity for the aircraft or escort ships to engage.

As for the actual conversions, I would make the same suggestion as in the earlier discussion about AA improvements to light cruisers, to modify individual ships as they rotate through the shipyards for repair or upkeep. In the case of tankers we could also incorporate MAC facilities in ships under construction; this will allow us to match the pace of conversions to the actual war situation. Saving even a few ships from being sunk will compensate for the out-of-service time.

One other thing that I would mention, the Japanese started the war with just barely enough shipping and soon ran short.
However, they didn't run convoys, so if you choose to do that you will lose 30% - 40% of your capacity.

Good point for the group to consider, should we back off on the rigorous implementation of convoy for logistic traffic until we see how much of a threat enemy subs really present? The 30-40% figure is consistent with the drop in imports to Britain cited by Blair in Hitler's U-Boat War; on the other hand the impact is proportional to the size of convoys and therefore the time involved in assembling and unload them.

Have you discussed building frigates or sloops instead of destroyers?

We have plans for escort ships, although we have not discussed curtailing construction of destroyers for them. It appears that we will complete only about thirty fleet destroyers through 1944 (Yugumo, Akizuki classes, Shimakaze), hardly excessive. Hopefully we can find additional capacity for escorts. The 1941 construction program includes Etorofu/Mikura class ships; I had suggested scaling back to the 740-ton Type C/D which appears adequate for the distances over which our convoys will operate.

We've also considered AA/AS ships comparable to the British sloop, which would be a bit larger than necessary for our pure AS types. I suggest that the minimal useful AA armament would be two twin 3.9" with a Type 94 gunfire control system and one twin 40mm (in the superfiring position aft for excellent sky arcs). This would require about 1000 tons; it might just be accommodated on an Etorofu. Personally I'd like to see two more twin 40s (sided amidships) which would probably cost another 100-200 tons.

Skipping ahead, the AA escort resembles the Matsu class escort destroyers, which were attractive ships; it's a question of. torpedos and a little more speed vs. improved AA capability.

 

Since the G3M "Nell" is being relegated to second line use, it would also make an ideal ASW aircraft.

WRT aerial depth bombs, we have 2. The small 60kg Type 99 Number 6 Mark 2 which was adopted in 1940, and the larger 250kg Type 1 Number 25 Mark 2 which was adopted in 1941. Also, in a pinch, standard general-purpose bombs could be used with an appropriate time delay or instantaneous fuse.

It is also worth noting that the depth bomb fuses were not hydrostatic, but time delay. As such, the time delay could not be adjusted once the aircraft took off. There were 4 types of fuses; one that was variable for between 0 and 1.5 seconds delay(0-50 feet depth), a 3.5 second delay(80 feet), a 6 second delay(150 feet), and a 17 second delay(300 feet).

For more information see:
http://www.fischer-tropsch.org/prim...Reports/USNTMJ-200E-0465-0531 Report 0-23.pdf
pages 26-29

and

HyperWar: War Damage Report 58: Submarine Report [Section 3]
Sections 3-15, 3-16, and 3-17.

 

WRT Taiyo,

http://www.fischer-tropsch.org/prim...Reports/USNTMJ-200A-0560-0608 Report A-11.pdf
in Table 3 on page 19, lists the Taiyo as having a Type 3 Model 10 and Type 3 Model 11 arresting gear, with 4 wires per unit, for a total of 8 wires. However, going on the basis of one Japanese naming convention, the Type 3 arresting gear would have been introduced in the Japanese year 2603 or, for Westerners, 1943. So, at least sometime during her life, the Taiyo was equipped with arresting gear(even if not originally).

 

Unlike the Atlantic there are no areas between the SER and Japan that cannot be covered by land based aircraft so we may not need A/C for scouting but the actual HK groups. This also means that convoys can be covered enroute by groups besides escorts. One thing to prepare for is that the presence of choke points makes it easier for mining. In the game I have not had much success, but In reality it could be a problem.

 

Secretary Michizane,

Your suggestion about the proposed MACs seems prudent. We could start with one conversion right now and begin running rigorous exercises to test the concept. We have just requisitioned a number of tankers for conversion to auxiliary fleet oilers. Itsukushima Maru is one such and she is scheduled to arrive at Kure for refitting on 25 November. Alternately Toa Maru might serve. She's currently at Kure finishing her conversion. She's should be completed by 15 October. I hate to take a fleet oiler back out of service, but we could start on her immediately and since we've canceled the Pearl Harbor operation we should be able to squeak by on one less oiler for now. Slap a deck and some arresting gear on her and see how it works. Assign, lets say six of our spare Aichi D1As as an initial air group.

We also have several submarines just coming off the ways. I-25 is just commissioning in Kobe and I-26 will come off the ways soon in Kure. I would suggest that a little game of thump tag with our new MAC, a few escorts, and some suitable "targets" might be precisely what the doctor ordered. It would be a wonderful way for the new boats to work up. We could temporarily assign Taiyo or any of the various submarines that were until recently assigned to the Pearl Harbor operation for exercises. As a matter of fact this would conceivably make a good subject for one part of our annual grand exercises, which I believe are about due up anyway. We could conceivably invite his majesty to watch and demonstrate what his new council plans to do. Such an invitation would surely show courage, and also demonstrate the stark difficulties of our path while showing the care we wish to take.

 

Also freebird: I don't think we need to actually institute convoys until we find ourselves at war with the United States at earliest. Dutch submarines will be a modest threat, but they are few and far from home and we can test our ASW ideas on them in a small way before dealing with the larger problem of the United States. We hope to delay U.S. entry into the war by at least six months, and perhaps a year or more. This will give us a little time to build additional merchants to create a little slack in the system so that we won't be squeezed so badly when we need to implement convoys. But we can certainly begin work on ASW assets in advance of anticipated hostilities. Hopefully we can make submarine warfare in our waters dangerous and expensive. British submarines could be a different matter. They have enough to do us injury, though if we can secure their bases against them it will do much to hamper them. War against Britain will do much to educate us for war with the United States.

 

I have no problem with increased emphasis on ASW, it seems reasonable especially considering the info poster earlier by Takao

OK, that seems reasonable in light of that.
BTW, what is your source for the KA-1 planned for use as ASW? (There's not too much on wiki)

You misunderstand me, I didn't assert that. I said that there's no evidence that carrier based aircraft are particularly effective, vs a very substantial cost.

Also seems pretty reasonable.

We propose to use merchant ships with a makeshift flight deck. (Thus the term MAC, which I will persist in using to describe these since I'm suggesting using them and not full conversions.) MAC is fine for the ship you describe, I would suggest "CVE" for A/C with hangers.

I would be cautious about assuming that you will face no threats, this could be as dangerous as Japan assuming that it didn't need to worry much about ASW.
Unless you plan to invade and occupy Australia, NZ, India Hawaii etc, there could always be the threat of long range anti-ship aircraft, and enemy naval action.
Japan may be in a better position, or you might force an agreement on them etc, however when planning years ahead (when building MACs vs CVE's) it would be better not to paint yourself in a corner. (IMO)

It's not the skill that I'm questioning, it's the ability to launch loaded aircraft from a small, short carrier.
Ryujo/Ryuho are very much different from a MAC in that they are 550'+ and can do 25 or 26 knots, which make operations much easier. (Ryujo is 512 but can make 29 knots) The Avenger/Bogue are only about 470' but they all had catapults.

This is probably a question for one of those with more aircraft expertise than mine, would a deck takeoff from a very short (450' - 500') carrier that can only make 13 or 14 knots be a problem?

I'm not out to prove anything to you here, but just using the best info that I can find.
I use Hazegray.org, but I'd be interested to see if you have different info.
World Aircraft Carriers List: Japanese Aircraft Carriers

I had more of a question on whether there was any reasonable basis for Japan to be planning ASW carrier operations in 1941 or if it was 20/20 hindsight, I think you've answered that. MAC's weren't something that the Japan ever used, despite the availability. I suppose they could have made them if they wanted to, but they didn't think they were useful.

 

I asked an "out of game" question, so it's not something that the (in game) Prime Minister can ajudicate.

I'm asking some questions when I have some doubt that it would be reasonable for Japan to do something, and if you have a plausible explanation for doing it.
If you can explain why they could have done it then it would be reasonable to do it in your simulation.

Carronade - about the loss of capacity by implementing convoys - yes the larger convoys are harder to organize (read - greater loss of efficiancy), however the (proposed) smaller Japanese convoys run into another problem - overloading the low capacity ports in the SRA. For example, instead of sending two tankers every day to Borneo, the IJN runs all 14 together as a convoy with protection. However, the oil port that they arrive at can't handle 14 tankers at once, so some of them have to wait days to unload. On the return voyage, some tankers have to wait 4 or 5 days after loading to move with the convoy.

It's something to consider.

SP, the big cost of MACs is that they will tie up a shipyard space for 6 - 10 months while the work is done, which subtracts the space & resources that one freighter that could have otherwise been built with. It might be better to construct a smaller number of more capable carriers, while still building the tankers etc that you so badly need.

Actually there is no need to build even one MAC first, just use the Hosho (or Ryujo etc) for testing, but back the ship off to about 13 or 14 knots max speed in low wind conditions, and see if you can take off loaded aircraft in 450 or 500 feet. Also embark some biplanes and see how effective they are at finding & attacking hidden subs. If it works, great! If it doesn't - then dump the idea of using MACs, keep the shipyards building freighters, and stick to the idea of Shoho or Chitose type CVE's (CVL's) conversions, which can be used for ASW and can still be used as auxilliary carriers with first-line aircraft