ORIGINAL: Bullwinkle58
Absolutley the only one useable, and they were a very small proportion of the U-boat fleet. The vast majority were Type VIIs.
I looked through the development of the boats of the various navies this morning, and was quite astonished to find that the US fleet-boat types, although almost 30% larger in displacement, had about the same range as the Type IX. I always thought they also had a larger range and longer endurance, but it would seem at least from that point the type IX are comparable. The VII were about 25% shorter legged, comparable to the British (Dutch) boats like the T-class. Another surprise I found was how little the British and Dutch boats actually contributed to the defeat of the IJ merchants, far less than 10% of sunk tonnage. I think I use their boats to much greater effect in the game in 42 alone.
ORIGINAL: Bullwinkle58
The Allies didn't have 3.5 years of warning and their efforts then sprang forth fully formed. They worked incrementally, experimenting. The Japanese had ample warning too. USN fleet boats were leaving Pearl on war patrol on 12/8/1941.
That's what I was pointing at. The British quickly felt the effect of the U-boats and knew them from WW1, so they rather quickly implemented measures and put a high priority on submarine warfare, ASW developments, convoys etc. Admittedly, the geography you described offered them less disadvantage points than the Japanese faced, but more important thing probably is that the Japanese were not recognizing the seriousness of the submarine threat they would face in late 43 or 44 before 1943.
I assume the lack of success of the fleetboats in 42 to mid 43 due to the duds, and their still comparably small number, made the Japanese underestimate that. Add to that a difference in doctrinal thinking since they themselves did not see subwarfare as merchant warfare against civilian ships, and they general cultural differences, and you can see why it took until the peaking losses in spring 44 for them to install a command and coordination structure for civil convoys, until they began increasing convoy sizes from some 5 to 10-20 ships with better escorts usage, or began looking at ASW warfare with more pressure. Too little too late, though. The Japanese never saw this coming.
ORIGINAL: Bullwinkle58
That they even managed to get flaot plane ASW up in many of their islands is remarkable, not a failure. But to expect them to be able to operate multi-engine, radar-equipped ASW from flyspecs in the DEI is nuts.
This is true, but imagine how it would change AE if you knew that as Japanese, there would be now measures possible to reduce the damage due to the merchant warfare one the fleet boats arrive in numbers and the torpedo problems go?
In my opinion it is fortunate that AE is not hardwired like this and one can implement a proper convoy system rather quickly (latest by conclusion of the expansion phase late-42), just as if the Japanese had not had the problems in coordinating large numbers of ships in a formation, with the escorts, with air, or even coordinating the various convoys itself. As if the measures they started to adopt mid-44, would already be started 12/41. Or even using hindsight to copy measures the Allies learned against the Germans. From training pilots in numbers in ASW duty to building up small airstrips at suitable locations in the DEI, SRA etc so one isn't stuck with float planes in 43/44. Using air cover to suppress boats selectively along the convoy lanes etc.
It is a lot of benefit one can gain from hindsight, and this is one aspect where I believe the Japanese floundered so badly, that there ought to be a good potential to last out longer even with the technical capabilities they had.
I tried to find the statistics on merchant losses from convoys/independent travelers, but I only found the statistics from the USN Administrations as published in 1947. I think it was the same table that I saw in Nimitz book a while back, which showed that the adoption of a strict convoy system lead to a reduction in Allied shipping loss by 60%. It is convoluted with all the other factors that also changed during the same time, though. Unfortunately I couldn't find any similar table for the PTO losses, but I mean to recall that I had found a PDF of a thesis from a USN student from the early 50s on the PTO that had a table of losses by origin and by travel. I can't find of remember where I originally got it.
Anyway, I tried to google for such a table, but instead hit a book that actually discusses this exact topic: "
Japanese Military Strategy in the Pacific War", James B. Wood, 2007. See page 53 following, he estimates that with a timely implementation of a proper convoy system the losses could have been reduced by 50%. The argumentation seems sound for what I know, though of course it is just an estimate, but it is the size of the improvements that I would say a Japanese player could expect with proper effort. Not sure how it is in Greyjoy's game -- are the losses of AK and TK far below 10-20 ships per month?