xthetenth wrote:The timing in a carrier operation is a very fine thing, and because they obsessively wargamed Pearl and carrier fights in general, the Japanese were likely keenly aware of how the difference between being found and hit or escaping unscathed could be made hours before they'd received any warning of it happening. If enemy carriers are around and the Japanese carriers are found, the Japanese would be at a massive disadvantage since they hadn't spotted the US carriers and wouldn't be able to necessarily get the first strike in, let alone get one off so much earlier that they'd be immune from strikes already launched.
Indeed, and also if the Japanese launch the third wave at Oahu, that means they have no reserve of planes to attack US carriers until the second wave is recovered and refueled and rearmed a couple hours later. Keeping the third wave in reserve gives them something to counter attack with, which is pretty important since the US carriers themselves are important targets. I forget if Japan was holding any ssignificant reserve of bombers for reconnaissance, I do believe they held back 40 fighters throughout the strikes for a CAP.
A full carrier strike could have been ruinous to Japanese plans, especially if one figures that the Japanese probably thought that the US would be better able to launch coordinated air strikes than they actually were.
Yeah, Japan had to assume US pilots were competent, which they effectively were not at that time.
To what degree would supplies ferried in through Persia and the Arctic be able to offset this loss? The Arctic was neither pretty nor fun, and I'd guess that the Persia route would add a ton of transit time to supplies, especially those from Pacific ports. Is an order of magnitude guess possible?
Historically the breakdown goes like this. About 17.5 million tons of cargo shipped from the western hemisphere to the USSR in total. Of this 23.8% came through Persia, 47.1% through the Far East, 22.7% through North Russian, 3.9% through the Black Sea (this was possible in 1945 after Greece fell to the British) and 2.5% came through the Artic which was mainly planes flown across from Alaska by US pilots. Pilots rode transport planes back home. That is a very hard tonnage to replace. Nothing could be done about it quickly.
Now these percentages are totals, all routes were developed and expanded over time, and for example for a number of summer months the allies refused to send any convoys to north Russia, allowing at times Persia to supply over 50% of deliveries for specific months, but overall nothing like that and generally its share is highest when total deliveries by all routes are lowest. But Persia only moved what it did in the first because the US sent 29,000 men to work on the transportation network, and assemble crated supplies like vehicles. It also employed a peak of over 40,000 civilians. Some of the work was done was pretty radical, entirely new docks were built, the railroad system completely overhauled, roads rebuilt, many supplies moved to Russia by road as well as rail and massive depot facilities established. It would be impossible to even equal the historical effort I’d say, if the US is not yet involved in the the war, or more likely entry into the war is delayed by lack of a Japanese attack. The local workforce was not effective enough, and the rail system still had to meet Iranian domestic needs (the US expanded it so much record numbers of Shi'a pilgrims were taken to Qom while still expanding cargo traffic...)
To ramble a bit, since this has come up before in my experience over the years and my ideas have refined a little, if the US is in the war then certainly all of that could be expanded, but the US Army was already pretty gung ho about what it did, any major increase in tonnage is only to occur with even more radical improvements like double tracking more of the rail system and building completely new bridges and tunnels in some instances. Some of specific projects could take a year or more. I believe pipelines were established, they could be increased in number so fuel movement at least should be easiest. All of this would have to be fed from bigger docks, bigger depots. All of that will take considerable time to expand and a lot of men and specialist engineering units which are hard to come by. I think you could ultimately replace a significant fraction of the Siberian tonnage, but it will be much more expensive to do so, and will consume a considerably larger pot of allied shipping. Especially as long as the Mediterranean is closed to supply convoys, forcing ships to go around Africa. The main difference would only be felt in 1943 and later, a serious limitation. Also the transport system on the Russian side may run into bottlenecks, though over time building ships from knocked down kits or even concrete on the Caspian Sea could overcome that. Still that's a big lead time kind of project.
More tonnage could go through the northern route by continuing convoy operations in the summer months that were historically abandon, but this would come with great risks and considerable losses into 1943 as well. The Germans might also make a bigger effort to try to take Murmansk after failing in 1941. The rail lines from Murmansk and Arkhangelsk, the latter of which cannot be used in winter, also placed restrictions on tonnage to a certain point. The land is pretty bad too, but Russia did build a diversion line for Murmansk, after the Finns cut the main line in 1941, pretty quickly.
For a brand new route, near the top of the top of the Urals, Russia historically extended a railway line during the war to access new sources of coal, this line could be and later was extended another 80 or so miles to reach the ocean but at a tiny town with no real port facilities. Google earth calls it Labynangi, I don’t think it was called that during the war. For a few months a year you could also barge supplies south down the Ob river. I think that's the Ob anyway, at least one of the big rivers can navigate all the way upsteam to the transiberian. This is in fact how supplies to build the railroad in the first delivered. Course it took what, nine years to build the damn line.
Labynangi is here if anyone is interested; appears to be primarily a timber port in the modern day and doesn't appear to be able to take deep draft vessels close to shore.
Anyway even with this development, it would be frozen in for at least half the year even with icebreaker operations. I suspect that coal rail line was also already pretty busy moving coal, but it might bring in a little more supply tonnage. Expanding the river port facilities would be difficult unless the Russians allowed the US to our right do the work, all the more so since the whole area is clearly swamps. Historically the Russians would not allow the allies to do anything in Russia, they barely allowed ships crews to leave, but with the Far East cut off they might be more willing to accept this. That might also help out in Persia to expedite the expanded flow of supplies northward.
BTW the data for supply tonnages came from this Army Green book, specifically on the Persian Corridor. http://www.history.army.mil/html/books/ ... ub_8-1.pdf
"This cult of special forces is as sensible as to form a Royal Corps of Tree Climbers and say that no soldier who does not wear its green hat with a bunch of oak leaves stuck in it should be expected to climb a tree"
— Field Marshal William Slim 1956