No announcement yet.

April 1942. Fleet Return to Japan Early

  • Filter
  • Time
  • Show
Clear All
new posts

  • April 1942. Fleet Return to Japan Early

    Kinda winging this one. Any experts on Japanese fleet deployments are welcome to provide info.

    After Op C part of Nagumos fleet was returned to Japans ports to prepare for the next set of operations.

    1. What ships returned to Japan & which ports did they return to?

    2. Japanese naval intelligence warned of US carrier activity in the north Pacific & of the possibility of a carrier raid on the home islands. Given this warning what changes might there have been to returning fleet elements port assignments? For this I have to note the only practical measure the Japanese naval commanders did in response to the warning was to deploy a second picket line 300nm further east @ 600nm from Japan. Is that likely to change?

    3. Had Nagumos fleet executed Op C a few days earlier & parts returned to Japan 24 to 48 hours before the execution of the USN raid would any elements been exposed to US attack?

    4. I am looking at the damage to the submarine tender Taigei undergoing conversion to a light carrier (Ryuho). Most sources state the 500lb bomb hit damage delayed the converion by some six months. Would a similar hit on any of the fleet carriers have caused a similar delay in combat readiness?

  • #2
    Not really answering your question and I am certainly not an expert but...

    According to, the Kido Butai passed Singapore by nightfall on 13th April 1942. It is 3760 nm from Singapore to Yokohama and thus Akagi was still south of Formosa when news of the Doolittle Raid arrived, apparently on the 19th April, which suggests that the IJN reacted rather slowly. That timing is consistent with the Kido Butai making 14-16 knots. If for some reason, such as a desire to carry out extensive training of new aircrews before further operations, the Kido Butai had been ordered to make 20 knots from the evening of 9th April, then the Kido Butai can be at the Bashi Channel approximately 3 days earlier, perhaps at nightfall on the 15th. Reading Akagi's TROM, we are told that Shokaku and Zuikaku were detached from 14th April. Their own TROM suggests that they were detached later but tells us that they docked at Mako in the Pescadores on the 18th. Thus Shokaku and Zuikaku presumably accelerated after they detached, so that they are at least a day ahead of Akagi, Hiryu and Soryu by the 18th. The problem is that Carrier Division 5 stopped at Mako to take on fuel. OTL Akagi, Hiryu and Soryu had enough fuel to comfortably reach Sasebo even after making a short run north east to try to find the Doolittle Raid. The TROMs for the Kongo class battleships mention that they were refuelled at sea on 15th April but it is not clear if the carriers took on any fuel. If the carriers had been travelling at 20 knots, they would have burnt much more fuel. However, we could imagine that they refuelled from the oilers that OTL supplied the battleships and that the battleships steamed slowly for Mako. All seven of the heavy cruisers involved in the Indian Ocean Raid were also in the region and OTL all arrive at Home Island ports on 22nd April. As Ozawa's Force had docked at Singapore on the 11th, at least those cruisers can keep up with the carriers without needing more fuel. The problem is the destroyers. If Yamamoto wants Akagi, Hiryu and Soryu to lift up their skirts and run, he is going to have to supply a relay of destroyers.

    We now have Akagi, Hiryu and Soryu with some heavy cruisers and new destroyers just south of Formosa as night falls on the 15th. That is about 700 nm from Kagoshima and Yokosuka is roughly another 500 nm North East. Thus it is not too hard to get those ships to approach Tokyo Bay during the 18th as they are covering 480 nm per day at 20 knots (perhaps slightly less due to zigzagging).

    We may now want to have the engines of Japanese picket boat No. 23 Nittō Maru breakdown so that she does not encounter the Americans at 0738 but allows them to approach another 170 nm as planned. If the delayed picket boat or an aircraft sent to replace it can sight the Americans at 1700 and the signal reaches Nagumo just South of Tokyo Bay almost immediately, he will be 500 nm West of Enterprise and Hornet. If Nagumo has been fully refuelled around the 15th, it is just possible that he can run for about 60 hours at around 25 knots. If he is very lucky, he will be 200 nm from the Americans on the morning of 21st April and about 1500 nm from Japan. He will be looking with great concern at his fuel gauges but his appearance may come as a surprise to the American force.


    • #3
      Thanks for that information. Main thing I am looking at here is if any additional ships, or rather carriers would have been in any port the US attacked on the 19th. How they could have been there is more a function of Operations C staying closer to schedule by a few days.

      ... the Kido Butai passed Singapore by nightfall on 13th April 1942. It is 3760 nm from Singapore to Yokohama and thus Akagi was still south of Formosa when news of the Doolittle Raid arrived, apparently on the 19th April, which suggests that the IJN reacted rather slowly.
      This actually a bit further along towards their destinations than I'd have guessed, and that they KB was not accelerated towards Japan in response to the intel report does indeed suggest some commanders were reacting slowly, or judging priorities differently than others might. The commanders back in Japan took the warning seriously enough to extend the picket screen, but I'm unaware of any other significant actions taken there. The misjudgment of the strike range of the possible US raid does not seem explain this entirely. They must have had other reasons for reacting so slowly. Or perhaps I am misunderstanding their thinking?

      Anyway this came up while I was reviewing some notes concerning air attacks on ships in 1942 & the note about the Taigei led to consideration of if a carrier/s had been in a attacked port.


      • #4
        All the large ships I have done duty on had "best economy" speeds of 12-14 knots, so the 14-16 knots sounds very reasonable for normal steaming.
        Hyperwar: World War II on the World Wide Web
        Hyperwar, Whats New
        World War II Resources
        The best place in the world to "work".


        • #5
          Looks like the Akagi was the only carrier sent to Yokosuka, which was the only port attacked - by one B25. So, worst likely case is the Akagi takes two 500lb bombs out of four dropped & a few incendiaries scattered about. More likely is it takes just one.

          Actually worst case is the bomb has a delay on the fuze & penetrates to a hot boiler. But, as the physics joke goes; What are the odds of that happening?


          Latest Topics