Yamamoto's Plan; The Execution

[el cid again]

ORIGINAL: JWE

ORIGINAL: witpqs

Sara was in San Diego - what - a week's journey? She would be late.

Very likely so. As I see it, the scenario would maybe go as follows:

Dec. 3, 4, or 5 (increasing probability with day) somebody, somewhere, says ‘Holy Shimoly! Convoy JN-12 is taking a course for the (Central) (Northern) Pacific’. Human nature being what it is, the first target list would include Midway, the Aleutians, and (at the bottom) the Hawaiians. Wake might be on the list, but source and routing would preclude that. The time calculation, to whatever objective, is a 2 – 3 minute exercise.

So you might get a better, faster, beefier reinforcement to Midway (maybe Wake), and the carriers would be put into relevant positions. If it were me, I would accelerate Sara’s load out but keep her in hand, to see which way the banzai bounces. I would probably have her on course to PH, on the northern track, on the 5th, no later than the 6th. So Sara might show up only a day or two ahead of historical schedule.

The problem with this - which isn't all bad - is that you have no idea what a group of ships is doing. Our maps are linear - but the world is spherical - and there are various methods used to navigate. It isn't a 2-3 minute exercise to figure out where a convoy is going - even if it is not tricky - and a smart convoy leader may mess you up by deliberately changing course - doubly so when someone sees a patrol plane far away. Not knowing what is on board, you do not know if this is infantry, support elements, or purely supplies either? It is just one piece in a puzzle - and you only know some of the data about that piece.

In spite of the poorly stated analysis of contact JN-12, the conclusions are not unreasonable - if some hostile intent were attributed to it (even an incorrect analysis that was hostile might generate a response). But since the main forward forces are coming up from Kwajalein -

a) There would be no reason to assume Aleutians objectives

b) Wake or Johnston would likely be suspected objectives for their respective invasion forces in particular

c) IF an initial op group headed for any of the lower islands - chances of detection are far less: on fast ships, covered by carrier fighters and air ASW patrols - getting a good sighting report on these ships would be pretty hard. Yet as the distance to the objective closes, at some point the chance of detection becomes so high as to be probable. Here the question is "how far out"???

In all three cases, this cannot give the US strategic warning - because the ships do not have to leave Kwajelein many days out. The detection probability increases dramatically as the objectives are approached, so for most cases, the game engine is going to work it out perfectly. Yes - you detected them - and understood the target - but it is x hours out - not y days or weeks out. To the degree signals intel and partial reports alerted you to be worried - that is covered by letting the Allied player(s) write whatever orders they want. And - note - this very fast and easy to implement - since it requires no work for the modder. It is easy to say "do this" - and then need 60 man days work to do it. So it is nice when you don't have to go that way. In this case, we don't.

[el cid again]

ORIGINAL: JWE

ORIGINAL: el cid again

Problem with the 1 MarDiv is that it had been broken up - that is its vets were forming up all sorts of Marine units all over the place (and mainly not PTO). The unit was very green - and IF it was sent forward sooner - it should be rated that way. Also it was short of weapons - and so many heavy weapons should be disabled (which only means they have half value) - while there were plenty of rifles.

Only 1 regiment was substantially picked over, and not till after Jan. 1942. The remainder were Marines. Only difference was they had Springfields instead of Garrands, rest of the kit was full. Had full complement of heavy weapons and extras in Special Weaps Bn.

Well - that is what I read somewhere. The division was not considered fit to fight. And note that the Marine division that went into Guadalcanal (2nd wasn't it?) NEVER had time to exercise at regimental level - never mind at divisional level. This was not the Marines as they like to be - trained fully up. If I am not confused, the First Division was considered less ready than the 2nd.

[el cid again]

ORIGINAL: JWE

ORIGINAL: el cid again

ORIGINAL: witpqs

Sara was in San Diego - what - a week's journey? She would be late.

Sailing from Long Beach - took us two weeks to reach Hawaii. Yeah - she will be late - or the US has strategic warning.

Must have been a dog. 2 years ago we sailed the Transpac on a Santa Cruz 52 in 11 days. Out of LA, though, not SD.

Anyway, nobody suggested Sara would be available at pearl. Yes, she would not have been in time for the party. So ??

Somebody DID suggest it - above. I think she could have been given orders and be en route - and that means the game works as is. You seem to give orders on Dec 7 - but your ships often sail for several days.

Transit times are a function of speed - of course. But in those days the critical problem was boiler feedwater - we don't have steamships now. Smaller ships do not make feedwater as fast as they consume it - so they cannot SUSTAIN high speeds. Further - carrier skippers want fuel in the tanks if they must maneuver in battle. Games get this all wrong - you can NOT make a STRATEGIC deployment of a carrier fast: you spend MONTHS planning it - getting the oilers in position - etc. Lots of things need to happen - and it is far too easy in war games - creating the impression of mobile power that is not quite real. And remember - we are talking peacetime Navy here. Warning there may be - but we are not at war - so we won't do things on a war emergency basis - until after that message "Air Raid, Pearl Harbor: This is no Drill" is heard.

[herwin]

300 vessels in the amphibious force was the USN prewar planning number for M+60 days. This was to support a corps-sized operation.

700 hours for the fleet to assemble at Pearl Harbor was USN prewar planning under the assumption that the Panama Canal was undamaged.

Sara to Pearl at 30 knots actually happened.

The early detection of the invasion convoys is based on the fact that the Navy had and was using the necessary intelligence and analysis assets in 1941. We might use computers today, but we knew our job then.

I agree the early invasions would have used about a division (a regiment at Midway; a reinforced battalion at Johnston; the rest at Kauai or one of the other islands) and about 100 vessels. BUT, there would have been enough warning to go to a wartime footing, reinforce with ships from the West Coast, and redeploy the at-hand assets within the HI. After that, it's a question of who could reinforce faster, with America basing its defence around a major fleet base.

[el cid again]

[quote]ORIGINAL: herwin

300 vessels in the amphibious force was the USN prewar planning number for M+60 days. This was to support a corps-sized operation.

REPLY: Sounds right. In the case of an Oahu invasion in 1941, not counting all planning and intelligence staff work since 1910, Japan had about 300 days from the decision for war until the first day of the war - and at least another 60 days before M day on Oahu.

700 hours for the fleet to assemble at Pearl Harbor was USN prewar planning under the assumption that the Panama Canal was undamaged.

Sara to Pearl at 30 knots actually happened.

REPLY: Maybe it did. Sara was a very unusual ship - she once ran the City of Tacoma electrical grid in an emergency. But do not confuse that with a combat battlegroup capability. She could not make such a run with destroyers. Nor could she do so and arrive on station with the fuel her captain would want for battle. [If you knew any carrier skippers - think about their attitude about fuel state - and you will realize this is the case] This isn't the logistical norm, and it isn't wise to think in such terms. A 30 knot run is "battle speed" - and itself may not be possible in all conditions even if the ship can turn the screws for that speed. Actual distance traveled through the water is not the same as distance moved over the ground under the water - due to wind and current. I have seen a ship turning for 18 knots and making 3 knots good - and a big ship has more trouble with wind than a small one does. A figure "so many hours point x to point y" as you passed out properly should be done at fleet or force crusing speed - which can be sustained in all but the worst conditions - and which can be done for a force that is balanced with small ships - and which can arrive with some reasonable amount of fuel if one must immediately go into battle. Since I made the run to Hawaii on a destroyer - and since we had no tankers - and since we had two WWII era destroyers in the division - we made the run at a reasonable speed - so they would not have to come out and rescue us.

[el cid again]

ORIGINAL: herwin


The early detection of the invasion convoys is based on the fact that the Navy had and was using the necessary intelligence and analysis assets in 1941. We might use computers today, but we knew our job then.

REPLY: Really? How come we lost the entire battle line at Pearl Harbor then? Why were we looking in the wrong direction for their striking force? Why were two carriers caught at sea delivering planes when it was too late for them to be on such an operation? There is pretty clear evidence RN signals intel at Singapore calculated when the war could begin as the day it really did begin - the wife of the captain in charge has published a book about what he did to notify us - against instructions from London. But still we were cought flat footed in both Central Pacific and Far East. Turns out that having the data somewhere in the system is not the same as comprehending it at the level of Adm Kimmel and Adm King.
I am sympathetic with how hard it is. I am not sympathetic with a claim we did a great job of it - or that no matter how the data varied we would understand it. We did NOT understand the KB was going to Hawaii - and there is some evidence we had some indicators it was. I granted above that the invasions will be detected - but where and when is not at all clear. It is really uncertain and that is what a game is best suited to tell us: if we hard wire it in there is no uncertainty at all. Let the players get the contact reports - and if they understand their significance - and if they have time (a day to work up orders) - let them react in a decisive way. And if they can guess what might be happening - also let them issue intelligent orders on the guess. In fact - there are lots of ways a force can come in - change course - change speed - and you won't know what they are up to specifically in any given game: hard wiring the reaction is inherantly less fair and right than letting players game it out.


I agree the early invasions would have used about a division (a regiment at Midway; a reinforced battalion at Johnston; the rest at Kauai or one of the other islands) and about 100 vessels. BUT, there would have been enough warning to go to a wartime footing, reinforce with ships from the West Coast, and redeploy the at-hand assets within the HI. After that, it's a question of who could reinforce faster, with America basing its defence around a major fleet base.

REPLY: What is "enough warning"??? I think you are talking many days - a week at least and more likely two to really change things like ships going from the West Coast to Hawaii. In the game you just say "go" - but IRL that isn't how it works. And since it isn't wartime - the urgency to do it would be absent. It is hard to explain how the Navy works - but it is not really any different in the Cold War era: I have seen a Soviet bomber makeing a run in on a US warship - to the point the next thing that happens is we figure out the missile(s) is away - but no one will raise our condition of readiness, warm up our radars or weapons, man our CIC or weapons, shut watertight doors, name it. The OOD says "I know he isn't really attacking" - and - if he is wrong - too bad for us. In my view the chances of 2 days warning is significant but far below probable (51%) - the chance of less than 1 days warning is high but nothing like certain (85 - 90%) - and the chance of 3 days or more warning vanishingly small (measured in single digit % - and not high single digits either). The farther out they are - the vastly greater the area they might be in is - the less clear it is what it means when you get a contact report (which almost certainly will be less than complete or less than totally accurate). IF you DID get a report (target 12 - no flag - position x,y - course abc, speed mn, 4 large ships, 2 smaller)* - odds are ALL that it would cause is some sort of effort to get more information (send out a PBY to search - at first light tomarrow - the area ahead if it stays on course abc at speed mn). You won't send ships to PH based on that - and that is the sort of thing you get if you are lucky. You cannot get a picture similar to Midway or even Coral Sea unless we have a code breakthrough - and unless they are stupid. At the start of a war - sailing from home waters - with a plan already in place (no need to change the orders - they exist) - you sail with orders you unseal/reval at sea - no traffic at all. That is what IJN really did do when the war began - so assuming anything else isn't wise. I have seen references to radio intercepts in this Forum that imply we knew what was up. Yet IRL we didn't know - even in the few cases we had good intel. [Our Allies could read - and fed us - the merchant code. THEY figured out when the war starts by when the ships were told to be in home waters - Dec 7 US time. But it didn't mean we knew the war was going to start on Dec 7. We didn't. And if we did - why didn't the carrier sail from the West Coast - and the other sail to meet her and form up the best possible battle group we could assemble? Why was the battlefleet not at sea or a different port? Because we did not know.]

* The report was of a convoy of more ships than that, but the submarine, low down in the sea or using a persicope, could not see more than that.

[herwin]

ORIGINAL: el cid again

ORIGINAL: herwin

300 vessels in the amphibious force was the USN prewar planning number for M+60 days. This was to support a corps-sized operation.

REPLY: Sounds right. In the case of an Oahu invasion in 1941, not counting all planning and intelligence staff work since 1910, Japan had about 300 days from the decision for war until the first day of the war - and at least another 60 days before M day on Oahu.

700 hours for the fleet to assemble at Pearl Harbor was USN prewar planning under the assumption that the Panama Canal was undamaged.

Sara to Pearl at 30 knots actually happened.

REPLY: Maybe it did. Sara was a very unusual ship - she once ran the City of Tacoma electrical grid in an emergency. But do not confuse that with a combat battlegroup capability. She could not make such a run with destroyers. Nor could she do so and arrive on station with the fuel her captain would want for battle. [If you knew any carrier skippers - think about their attitude about fuel state - and you will realize this is the case] This isn't the logistical norm, and it isn't wise to think in such terms. A 30 knot run is "battle speed" - and itself may not be possible in all conditions even if the ship can turn the screws for that speed. Actual distance traveled through the water is not the same as distance moved over the ground under the water - due to wind and current. I have seen a ship turning for 18 knots and making 3 knots good - and a big ship has more trouble with wind than a small one does. A figure "so many hours point x to point y" as you passed out properly should be done at fleet or force crusing speed - which can be sustained in all but the worst conditions - and which can be done for a force that is balanced with small ships - and which can arrive with some reasonable amount of fuel if one must immediately go into battle. Since I made the run to Hawaii on a destroyer - and since we had no tankers - and since we had two WWII era destroyers in the division - we made the run at a reasonable speed - so they would not have to come out and rescue us.

She didn't need to bring her DDs along. Maybe not even her cruisers. Doctrine allowed her to shed her escorts when appropriate--for example if they were needed for a gunship action or she needed to make a fast run. A vessel doing 30 knots was almost immune to submarine attack. Most of the large liners sailed independently for this reason.

[herwin]

ORIGINAL: el cid again

ORIGINAL: herwin


The early detection of the invasion convoys is based on the fact that the Navy had and was using the necessary intelligence and analysis assets in 1941. We might use computers today, but we knew our job then.

REPLY: Really? How come we lost the entire battle line at Pearl Harbor then? Why were we looking in the wrong direction for their striking force? Why were two carriers caught at sea delivering planes when it was too late for them to be on such an operation? There is pretty clear evidence RN signals intel at Singapore calculated when the war could begin as the day it really did begin - the wife of the captain in charge has published a book about what he did to notify us - against instructions from London. But still we were cought flat footed in both Central Pacific and Far East. Turns out that having the data somewhere in the system is not the same as comprehending it at the level of Adm Kimmel and Adm King.
I am sympathetic with how hard it is. I am not sympathetic with a claim we did a great job of it - or that no matter how the data varied we would understand it. We did NOT understand the KB was going to Hawaii - and there is some evidence we had some indicators it was. I granted above that the invasions will be detected - but where and when is not at all clear. It is really uncertain and that is what a game is best suited to tell us: if we hard wire it in there is no uncertainty at all. Let the players get the contact reports - and if they understand their significance - and if they have time (a day to work up orders) - let them react in a decisive way. And if they can guess what might be happening - also let them issue intelligent orders on the guess. In fact - there are lots of ways a force can come in - change course - change speed - and you won't know what they are up to specifically in any given game: hard wiring the reaction is inherantly less fair and right than letting players game it out.


I agree the early invasions would have used about a division (a regiment at Midway; a reinforced battalion at Johnston; the rest at Kauai or one of the other islands) and about 100 vessels. BUT, there would have been enough warning to go to a wartime footing, reinforce with ships from the West Coast, and redeploy the at-hand assets within the HI. After that, it's a question of who could reinforce faster, with America basing its defence around a major fleet base.

REPLY: What is "enough warning"??? I think you are talking many days - a week at least and more likely two to really change things like ships going from the West Coast to Hawaii. In the game you just say "go" - but IRL that isn't how it works. And since it isn't wartime - the urgency to do it would be absent. It is hard to explain how the Navy works - but it is not really any different in the Cold War era: I have seen a Soviet bomber makeing a run in on a US warship - to the point the next thing that happens is we figure out the missile(s) is away - but no one will raise our condition of readiness, warm up our radars or weapons, man our CIC or weapons, shut watertight doors, name it. The OOD says "I know he isn't really attacking" - and - if he is wrong - too bad for us. In my view the chances of 2 days warning is significant but far below probable (51%) - the chance of less than 1 days warning is high but nothing like certain (85 - 90%) - and the chance of 3 days or more warning vanishingly small (measured in single digit % - and not high single digits either). The farther out they are - the vastly greater the area they might be in is - the less clear it is what it means when you get a contact report (which almost certainly will be less than complete or less than totally accurate). IF you DID get a report (target 12 - no flag - position x,y - course abc, speed mn, 4 large ships, 2 smaller) - odds are ALL that it would cause is some sort of effort to get more information (send out a PBY to search - at first light tomarrow - the area ahead if it stays on course abc at speed mn). You won't send ships to PH based on that - and that is the sort of thing you get if you are lucky. You cannot get a picture similar to Midway or even Coral Sea unless we have a code breakthrough - and unless they are stupid. At the start of a war - sailing from home waters - with a plan already in place (no need to change the orders - they exist) - you sail with orders you unseal/reval at sea - no traffic at all. That is what IJN really did do when the war began - so assuming anything else isn't wise. I have seen references to radio intercepts in this Forum that imply we knew what was up. Yet IRL we didn't know - even in the few cases we had good intel. [Our Allies could read - and fed us - the merchant code. THEY figured out when the war starts by when the ships were told to be in home waters - Dec 7 US time. But it didn't mean we knew the war was going to start on Dec 7. We didn't. And if we did - why didn't the carrier sail from the West Coast - and the other sail to meet her and form up the best possible battle group we could assemble? Why was the battlefleet not at sea or a different port? Because we did not know.]

There's a difference between a raid and an invasion. The KB caught us flat-footed because it had excellent operational security, came in from an unexpected direction, was light on its feet (about a dozen escorts for six carriers), and didn't linger. Try doing that when you have a hundred or more amphibious vessels to shepherd. Rochefort was mostly watching for an invasion coming from the Mandates, not a carrier raid out of the blue.

I'm talking three weeks from an awareness that something major and long range was afoot, two weeks from knowledge that the target was to the east of New Guinea, not in the NEI, and one week from knowing that the target was probably in the Hawaiian Sea Frontier. Plenty of time.

[el cid again]

ORIGINAL: herwin

ORIGINAL: el cid again

ORIGINAL: herwin

300 vessels in the amphibious force was the USN prewar planning number for M+60 days. This was to support a corps-sized operation.

REPLY: Sounds right. In the case of an Oahu invasion in 1941, not counting all planning and intelligence staff work since 1910, Japan had about 300 days from the decision for war until the first day of the war - and at least another 60 days before M day on Oahu.

700 hours for the fleet to assemble at Pearl Harbor was USN prewar planning under the assumption that the Panama Canal was undamaged.

Sara to Pearl at 30 knots actually happened.

REPLY: Maybe it did. Sara was a very unusual ship - she once ran the City of Tacoma electrical grid in an emergency. But do not confuse that with a combat battlegroup capability. She could not make such a run with destroyers. Nor could she do so and arrive on station with the fuel her captain would want for battle. [If you knew any carrier skippers - think about their attitude about fuel state - and you will realize this is the case] This isn't the logistical norm, and it isn't wise to think in such terms. A 30 knot run is "battle speed" - and itself may not be possible in all conditions even if the ship can turn the screws for that speed. Actual distance traveled through the water is not the same as distance moved over the ground under the water - due to wind and current. I have seen a ship turning for 18 knots and making 3 knots good - and a big ship has more trouble with wind than a small one does. A figure "so many hours point x to point y" as you passed out properly should be done at fleet or force crusing speed - which can be sustained in all but the worst conditions - and which can be done for a force that is balanced with small ships - and which can arrive with some reasonable amount of fuel if one must immediately go into battle. Since I made the run to Hawaii on a destroyer - and since we had no tankers - and since we had two WWII era destroyers in the division - we made the run at a reasonable speed - so they would not have to come out and rescue us.

She didn't need to bring her DDs along. Maybe not even her cruisers. Doctrine allowed her to shed her escorts when appropriate--for example if they were needed for a gunship action or she needed to make a fast run. A vessel doing 30 knots was almost immune to submarine attack. Most of the large liners sailed independently for this reason.

Yes they did. So did USS Indianapolis. But as her case shows, a high speed ship is not necessairily safe from a submarine attack. The sub skipper had guided torpedoes (Kaiten) - but did not need to use them - because it was a perfect shot. Too perfect - he had to back up to insure torpedoes would have minimal arming distance before they hit the target. The main reason the liners were not often sunk by submarines is that there were not often submarines near them. The Allies used very distant routes - routes the Axis could not economically contest - and they went to extraordinary lengths to conceal sailing times and courses. Indianapolis shows what can happen if it is in contested waters.

This is technical bantering to no purpose: you are missing the point: ships do not change theaters quickly as a rule - and certainly not because of first contact reports which can not yet make much sense. Japanese ships of any kind can sail the length of the Japanese controlled Mandates. We are not likely to know about it - we avoid the area ourselves and are pretty strongly encouraged to do so - except that parts of the B-17 route overflies parts of it - and so does the Clipper route. We tried very hard not to let the B-17s be seen - flying the unwelcome waters at night if possible. Chances are remote we would detect the forward formations several days out (they don't need many days) - and we have no basis for action while they remain in Japanese waters. Only after they leave these waters is there any chance of putting a clear threat intent on a sighting - and it would take more than a few hours to report that raw data up many echelons of burocracy - maybe days to reach the top. [On Dec 7 there was not good atmospherics in PTO - it could happen on other days too] Building in an automatic detection, successful interpretation, mandatory reaction hard wired is not reasonable. Using the game engine to detect operationally - and allowing players to decide what reactions are appropriate is easier, more fun, and far better simulation of probable events. Detection is almost certain - absolutely certain if you count when planes start arriving over some target or other. But early detection combined with proper analysis and then having us decide what the response must be is almost certainly going to be more wrong than right. Detection early would require luck. And then it still would more likely be "in the information pipeline" than fully appreciated by the time it mattered. And even if someone knew - it might well be too late to do anythign about it - witness the attempts to give what warning we did on Dec 7 - it didn't reach the post until after the air strike did. A week before we had sent out a different alert - and had it wrong. It isn't easy to read intel tea leaves clearly - until AFTER you have 20-20 hindsight.

[herwin]

ORIGINAL: el cid again

Yes they did. So did USS Indianapolis. But as her case shows, a high speed ship is not necessairily safe from a submarine attack. The sub skipper had guided torpedoes (Kaiten) - but did not need to use them - because it was a perfect shot. Too perfect - he had to back up to insure torpedoes would have minimal arming distance before they hit the target. The main reason the liners were not often sunk by submarines is that there were not often submarines near them. The Allies used very distant routes - routes the Axis could not economically contest - and they went to extraordinary lengths to conceal sailing times and courses. Indianapolis shows what can happen if it is in contested waters.

This is technical bantering to no purpose: you are missing the point: ships do not change theaters quickly as a rule - and certainly not because of first contact reports which can not yet make much sense. Japanese ships of any kind can sail the length of the Japanese controlled Mandates. We are not likely to know about it - we avoid the area ourselves and are pretty strongly encouraged to do so - except that parts of the B-17 route overflies parts of it - and so does the Clipper route. We tried very hard not to let the B-17s be seen - flying the unwelcome waters at night if possible. Chances are remote we would detect the forward formations several days out (they don't need many days) - and we have no basis for action while they remain in Japanese waters. Only after they leave these waters is there any chance of putting a clear threat intent on a sighting - and it would take more than a few hours to report that raw data up many echelons of burocracy - maybe days to reach the top. [On Dec 7 there was not good atmospherics in PTO - it could happen on other days too] Building in an automatic detection, successful interpretation, mandatory reaction hard wired is not reasonable. Using the game engine to detect operationally - and allowing players to decide what reactions are appropriate is easier, more fun, and far better simulation of probable events. Detection is almost certain - absolutely certain if you count when planes start arriving over some target or other. But early detection combined with proper analysis and then having us decide what the response must be is almost certainly going to be more wrong than right. Detection early would require luck. And then it still would more likely be "in the information pipeline" than fully appreciated by the time it mattered. And even if someone knew - it might well be too late to do anythign about it - witness the attempts to give what warning we did on Dec 7 - it didn't reach the post until after the air strike did. A week before we had sent out a different alert - and had it wrong. It isn't easy to read intel tea leaves clearly - until AFTER you have 20-20 hindsight.

The Indianapolis established a record time from San Francisco to Pearl Harbor in July 1945--74.5 hours. Then she sustained 24 knots to the Marianas. After delivering the bomb to Tinian, she headed to Leyte, with a sustained speed of 15.7 knots. She was not zigzagging the night of 29/30 July when she was torpedoed; she was doing cruise speed on a steady course. Sara was about four or five days away from Pearl Harbor in an emergency. (http://www.history.navy.mil/faqs/faq30-7.htm)

The USN had planned the relief of Hawaii in 30 days for use on an as-needed basis. (War Plan Orange, 1935)

With regard to the 'technical bantering', there is a marked difference between a carrier TF on a raid and an amphibious TF crossing half the Pacific. Japanese operational security was poor for amphibious operations, and the indicators would have lit up. Even prior to WWII, some senior USN admirals understood the value of intelligence, and it wasn't accidental that Rochefort was running the shop in Hawaii. (http://www.history.navy.mil/books/comint/index.html) We were reading the Japanese merchant/navy liaison code as early as 1941.

I'm going to add a bit on the Midway operation.

We were aware something was up in March.

We were tracking elements of the operation and putting the pieces together in April.

We knew the target in May.

The battle took place in early June.

These were the same analysts who had a rather good finger on the Japanese pulse in the second half of 1941 (except for the Pearl Harbor attack). They were stretched to the limit and the Japanese changed their codes in November 1941. That with a failure to track call signs meant that the KB got lost. They would certainly have been tracking the Amph TF intended for use against Hawaii.

The suggestion that we would have deliberately avoided tracking Japanese forces is belied by what we were actually doing in the Western Pacific. Perhaps some of the senior commanders and civilians in the Navy Department might have put out orders, but both you and I know intelligence officers don't operate that way.

[JWE]

ORIGINAL: el cid again

ORIGINAL: JWE

ORIGINAL: el cid again

Problem with the 1 MarDiv is that it had been broken up - that is its vets were forming up all sorts of Marine units all over the place (and mainly not PTO). The unit was very green - and IF it was sent forward sooner - it should be rated that way. Also it was short of weapons - and so many heavy weapons should be disabled (which only means they have half value) - while there were plenty of rifles.

Only 1 regiment was substantially picked over, and not till after Jan. 1942. The remainder were Marines. Only difference was they had Springfields instead of Garrands, rest of the kit was full. Had full complement of heavy weapons and extras in Special Weaps Bn.

Well - that is what I read somewhere. The division was not considered fit to fight. And note that the Marine division that went into Guadalcanal (2nd wasn't it?) NEVER had time to exercise at regimental level - never mind at divisional level. This was not the Marines as they like to be - trained fully up. If I am not confused, the First Division was considered less ready than the 2nd.

Holcomb and King considered them fit to fight. 1 MarDiv with 1st, 2nd, 5th and 11th marines, as well as other stuff, under command was at Guadalcanal. 7th Marines was in Samoa, but rejoined later. 2nd Marines was organic to 2 MarDiv. 5th and much of 1st Marines had undergone training rotation at Solomons Island. Their performance in action indicates training was sufficient. I’ll take them.

[bradfordkay]

Sid, I find it interesting that you seem to insist that the Saratoga couldn't possibly reach Hawaii in less than two weeks, but that an invasion TF could sail from Kwajalein to Hawaii in just a few days - a distance approximately 3/4's of the distance from SD to PH.

What was the main reason that allied intel was looking at the Malaya/PI area before the war started? Because that's where the Japanese troop convoys were. If we were able to track thsoe convoys from departure to landing, why do you feel that we would have been unable to track ones going to the Central Pacific? It seems like wishful thinking to me - of the sort that the IJN was quite known for holding.

You talk about the Wake and Johnson Is invasions coming as the first step, which makes sense. However, there is no basis for believing that once those invasions are detected (even if only one day out) that the Japanese could tactically surprise us with an Hawaiian invasion following on the heels of those invasions (strategic surprise, where the 2d Marine Division is still in SD is still possible, though if I had been in charge as soon as I'm told that there's a corps sized Japanese movement with unknown destination afoot I would have had them forwarded to Hawaii).

Putting together a convoy for three divisions invovles substantially more ships than a regular resupply convoy to Truk or Kwajalein. I am of the firm belief that the departure of such a large convoy from Japanese waters would not have gone undetected by US intelligence. They certainly did not miss the invasion convoys headed to Malaya.

[JWE]

ORIGINAL: bradfordkay

Sid, I find it interesting that you seem to insist that the Saratoga couldn't possibly reach Hawaii in less than two weeks, but that an invasion TF could sail from Kwajalein to Hawaii in just a few days - a distance approximately 3/4's of the distance from SD to PH.

What was the main reason that allied intel was looking at the Malaya/PI area before the war started? Because that's where the Japanese troop convoys were. If we were able to track thsoe convoys from departure to landing, why do you feel that we would have been unable to track ones going to the Central Pacific? It seems like wishful thinking to me - of the sort that the IJN was quite known for holding.

You talk about the Wake and Johnson Is invasions coming as the first step, which makes sense. However, there is no basis for believing that once those invasions are detected (even if only one day out) that the Japanese could tactically surprise us with an Hawaiian invasion following on the heels of those invasions (strategic surprise, where the 2d Marine Division is still in SD is still possible, though if I had been in charge as soon as I'm told that there's a corps sized Japanese movement with unknown destination afoot I would have had them forwarded to Hawaii).

Putting together a convoy for three divisions invovles substantially more ships than a regular resupply convoy to Truk or Kwajalein. I am of the firm belief that the departure of such a large convoy from Japanese waters would not have gone undetected by US intelligence. They certainly did not miss the invasion convoys headed to Malaya.

Brother bradford,

I don't know if you meant to raise it or not, but you imply an interesting point. Everyone seems to assume a Hawaiian invasion would organize in and clear from the mandates; most mentioned possibilities are Palau, or Kwaj.

Why the mandates, necessarily? Equally valid assumption might be from Japan proper.

The noise from an invasion TF would be more apparent when set against the background of the mandates, while possibly more easily misunderstood if uncovered in the home islands. If we identified a biggie in the mandates, likely all bets would be off for surprise anywhere in the central Pacific region.

If it was me, I wouldn’t stage that kind of exceptionally high risk op from a central Pacific region; I would keep things close to home till X-day.

Do you think the mandates? Like to have your take.

[el cid again]

[quote]ORIGINAL: herwin


The USN had planned the relief of Hawaii in 30 days for use on an as-needed basis. (War Plan Orange, 1935)

REPLY: If this is so - and I accept that it is but am not confirming it by independent knowledge - it is reasonable. There is no chance of 30 days warning. Pretty much end of this line of discussion: you cannot reasonably believe they had anything like that. Further - the situation is different in 1941: the "relief of Hawaii" by the United States Fleet based on San Francisco is no longer germane: the United States Fleet is ALREADY AT Hawaii - sort of "pre relieved" as it were. But that fleet cannot defend the place - and this was well understood by both Adm Richardson - who took it there - and Adm Kimmel - who got his job when Richardson tried to change the mind of FDR about the safety of the fleet at Ohau. There is not going to be any such relief in 30 days in 1941 - unless it is by two or three carriers (depending on assumptions).
Since they won't have 30 days warning - or half that - or a quarter of that - it isn't germane. Figure the sailing time Kwajalein to Johnston, Kwajalein to Wake, or wherever - you cannot get waring longer than that number of days.


With regard to the 'technical bantering', there is a marked difference between a carrier TF on a raid and an amphibious TF crossing half the Pacific. Japanese operational security was poor for amphibious operations, and the indicators would have lit up. Even prior to WWII, some senior USN admirals understood the value of intelligence, and it wasn't accidental that Rochefort was running the shop in Hawaii. (http://www.history.navy.mil/books/comint/index.html) We were reading the Japanese merchant/navy liaison code as early as 1941.


REPLY: And who said there is not any difference between a carrier TF and an amphib one? I served in both - so surely you know I have a clue how they are alike and how they differ. Not that they cannot be alike - but they rarely are. But it looks like you are engaged in some unsafe reasoning here: the small, lead elements might not be on merchant ships at all - or like the tanker task group - on unusual merchants which, among other things, did not use the liaison code (possibly the inclusion of a true auxiliary oiler was so her signalmen could serve the task group, and her captain could lead it; otherwise it may be they all had a navy signal detachment - similar to the way the IJA put a signal unit on some Navy auxiliaries and on some merchant ships). You cannot reasonably force the enemy to be incompetent or sloppy in some peculiar way you are able to exploit. Simulation gaming is not trying to LIMIT what the enemy can do UNLESS those limits are physical or grossly institutional. It is trying to show how various possible options might work out. Japanese signals are not something well understood even by specialists: some believe Japan "flooded the airwaves with fake messages" - some say "they dropped off the map - there were no signals" - and it is likely both are right - and wrong - in some sense - and oversimplifying - which is required to put a vast subject into a single phrase. Surely KB and her associated task elements were not using the radio much - there appears to be one instance of traffic with a submarine - and surely radio blackout was in place for Midway - it was cursed by Nagumo during the action. We cannot reasonably force the Japanese to betray their hand by SIGINT - and we certainly may not say on the record we exploited the SIGINT we had enough to save Hawaii from attack. Finally - why not begin the Central Pacific Campaign with a raid by KB? Just because other forces are following up does not mean the raiders must be tied to them for the initial run in?
We should let PLAYERS decide what to try - and let the game figure out what happens? Give em the forces - let em try various combinations of tactical and operational approaches. It is the interaction of such things on both sides that the game figures out - and well.

[el cid again]

ORIGINAL: herwin


I'm going to add a bit on the Midway operation.

We were aware something was up in March.

We were tracking elements of the operation and putting the pieces together in April.

We knew the target in May.

The battle took place in early June.

These were the same analysts who had a rather good finger on the Japanese pulse in the second half of 1941 (except for the Pearl Harbor attack). They were stretched to the limit and the Japanese changed their codes in November 1941. That with a failure to track call signs meant that the KB got lost. They would certainly have been tracking the Amph TF intended for use against Hawaii.


OK - fine. I have posted in the other thread that this op was viable in 1941 but not in 1942 for several reasons. One of those was the superb radio intel that was generated in 1942 which was NOT generated in 1941. We did NOT know "somewthing was up" in September, "tracking elements" in October, and we certainly did not "know the target" in November - or even in December. But the Japanese DID know the situation in Oahu very precisely - they had late and nearly real time updates (a submarine aircraft overflew and took photographs pre and post strike; two naval officers were on shore and sent a message on the current ships in port a day or so before; "other kind of people" (non Japanese agents) were in position as backup and confirming sources - and they had direct communication with a submarine).
The intel advantage is inherantly with the Japanese coming out of peacetime - they can have diplomats and agents in place - and we do not have any clear way to know when a war will start? To suggest we should impose 1942 conditions - Japanese diplomats are interned - the agents were captured (mostly anyway - you never know what you do not know) -
and the signals situation had improved substantially. Plus we knew we were at war. Entirely different situation.

The suggestion that we would have deliberately avoided tracking Japanese forces is belied by what we were actually doing in the Western Pacific. Perhaps some of the senior commanders and civilians in the Navy Department might have put out orders, but both you and I know intelligence officers don't operate that way.

No it is not. Flatly not. The only cases I am aware of involved agents who did not make it - did not even survive - and did not report. Agents in that era are not current sources of information (unless like the RAF officer in Malaya the agent has a radio to use - in that case an RAF radio - which he used to inform the Japanese in detail of current flight ops). I am not talking about agents - I don't think there were any at all in the Mandates in Dec 1941. I am talking about submarines, merchant ships, airplanes, or surface task elements (e.g. a CA escorting a merchant or two). These stood well clear of the mandates, except only the airplanes I mentioned (B-17s in transit and the Clipper). Other planes lacked the range (Amelia Airheart excepted - and she had permission) and the bases to operate from. We had no operational "eyes" in the mandates - unless it was a merchant ship that probably would not report what it saw in the first place. And if we did get a report - a report of Japanese ships in Japanese territory is not very meaningful.

Then there is the difference between an agent report and a military one. Never mind an agent may not know how to make a report useful to the Navy - he might or might not - he usually will report to INTEL. [The Japanese RAF officer was very unusual in that he reported directly to air operations; he was an operational asset - not a classical intel asset]
Intel organizations often will NEVER disclose what they learn - for fear of disclosing they have an agent somewhere. And when that is not the case, they usually DELAY disclosure until it can be "confirmation" of other data - or the agent is no longer at risk (being "confirmation" means no one can know it had to come from an agent - since it really came from another source as well - we might be betting on that source without confirmation). You want to persuade me that even a three day warning is useful - don't make it be from some German employee of a store on a Mandated island (or whatever- there are very few possible agents in Nanyo).

[el cid again]

ORIGINAL: JWE

ORIGINAL: el cid again

ORIGINAL: JWE



Only 1 regiment was substantially picked over, and not till after Jan. 1942. The remainder were Marines. Only difference was they had Springfields instead of Garrands, rest of the kit was full. Had full complement of heavy weapons and extras in Special Weaps Bn.

Well - that is what I read somewhere. The division was not considered fit to fight. And note that the Marine division that went into Guadalcanal (2nd wasn't it?) NEVER had time to exercise at regimental level - never mind at divisional level. This was not the Marines as they like to be - trained fully up. If I am not confused, the First Division was considered less ready than the 2nd.

Holcomb and King considered them fit to fight. 1 MarDiv with 1st, 2nd, 5th and 11th marines, as well as other stuff, under command was at Guadalcanal. 7th Marines was in Samoa, but rejoined later. 2nd Marines was organic to 2 MarDiv. 5th and much of 1st Marines had undergone training rotation at Solomons Island. Their performance in action indicates training was sufficient. I’ll take them.

The situation was desperate and dangerous. See the official navy history. They did not train up sufficiently - you should not field a division that never exercised as such, nor even at regimental level. I know one solider from the 25th Division who saw the Marines in action several times - and he felt they were poorly trained - too willing to take risks that cost them casualties. Part of that is a difference in doctrine - I know - trained originally by Marines, I joined a regiment led by Army officers late in life - and it really is different. But Guadalcanal does not seem very clever to me: it was too far for air support from friendly bases, we abandoned the troops before we offloaded their gear, and considering the enemy was badly outnumbered and only construction troops - we hardly could have lost no matter what we messed up. Later on it was catch up ball for the Japanese - and they never were really able to field a competative force - nor give it any reasonable amount of ammunition or supplies. Tsuji needed only minutes on the ground to understand things were very bad for IJA on Guadalcanal - and that far from any enemy. They were just plain bad, hopeless, no chance for most to even survive the natural opposition, never mind combat. I also once went to a US Army Jungle Warfare School - it has nothing whatever to do with warfare - it was a survival course - and it was then in a jungle much worse even than on Savo Island (which is quite horrible and inhabited by people who would eat you in 1941). Had First MARDIV actually been sent in against any sort of combat force - rather than airfield construction engineers - it would probably not be you would be very proud of the outcome. And that is pretty much the way the Marines teach it. Marines are big on lessons learned - how not to do it is more or less their religion.

[el cid again]

[quote]ORIGINAL: bradfordkay

Sid, I find it interesting that you seem to insist that the Saratoga couldn't possibly reach Hawaii in less than two weeks, but that an invasion TF could sail from Kwajalein to Hawaii in just a few days - a distance approximately 3/4's of the distance from SD to PH.

Interesting indeed. Because that isn't what I said. I said it would not. Different thing entirely. I have made the crossing on a fast warship in peacetime - and that isn't how we do it.

I also don't think an invasion task force of the classical sort would go to Hawaii in just a few days. Indeed, I have never tried to organize one - in decades of work on this matter. I think the Japanese lead forces must be fast raiders - either entirely in a carrier striking force - or on fast ships of some other sort - in small numbers too. In a more detailed game system, I usually try to have a small party of land raiders on a merchant ship of some sort that is NOT part of a task group but ostensibly on a civil mission: these I land on Lanai to back up the handful that land by parachute. Since a Japanese SNLF usually operated that way (one dropping element, one landing element) they could both be drawn from the same unit. But that is too detailed for us here: we have no COD aircraft in JNAAF, we have no way to simulate ships in some civil service that won't likely be suspected by players, etc. So I only use strait up task groups. And I think it is dangerous to put a raiding group forward - you may lose it - and you may betray the attack attempting to deliver it. Wise players may "hold back" the raiders for a day or two - and let KB go in alone. I think this sort of thing belongs in player hands - not hard wired. We cannot know when first detection will happen - and it should vary with the tactical decisions made by players and luck - not be forced by us in all cases to be the same. IF they get lots of warning - by all means - send ships from the West coast. Even if they don't get lots of warning - I think it is a good idea anyway!

[el cid again]

[quote]ORIGINAL: bradfordkay


What was the main reason that allied intel was looking at the Malaya/PI area before the war started? Because that's where the Japanese troop convoys were.

Actually not. The convoys were sighted in places like the Taiwan Strait - and we knew perfectly well they might be headed to Indochina or Hainan or South China.

Granted that changed at the very end - we did have sightings in the Gulf of Siam then. But you want MANY DAYS warning - and you cannot get it from ships that are near their destinations. Does not work like that. IF you know about them days out - you also do not know where they are going - for sure. That is less an issue in the Central Pacific - there isn't much there besides Hawaii. But you cannot know they are headed there before they leave. And they won't leave in time to give you many days warning. They don't have to. The critical times are Kwaj to Johnston for fast transports and Kwaj to near Hawaii for KB. About the only thing you have going for you there is it is a sector we patrolled. But we lacked the resources to do so exhaustively. [An official report given to Kimmel by two officers recommended 180 B-17s - and that to achieve about 24 hours warning. There was no way to get 180 B-17s to do it in 1941.]

[bradfordkay]

ORIGINAL: JWE




Brother bradford,

I don't know if you meant to raise it or not, but you imply an interesting point. Everyone seems to assume a Hawaiian invasion would organize in and clear from the mandates; most mentioned possibilities are Palau, or Kwaj.

Why the mandates, necessarily? Equally valid assumption might be from Japan proper.

The noise from an invasion TF would be more apparent when set against the background of the mandates, while possibly more easily misunderstood if uncovered in the home islands. If we identified a biggie in the mandates, likely all bets would be off for surprise anywhere in the central Pacific region.

If it was me, I wouldn’t stage that kind of exceptionally high risk op from a central Pacific region; I would keep things close to home till X-day.

Do you think the mandates? Like to have your take.

If you're going to invade Johnson Island, I believe that that invasion will have to come from or through the mandates. Otherwise, the task force will have to pass by or between Wake and Midway. Another reason for expecting an invasion force to at least come through the mandates is that this was an area where we had little intelligence or reconassaince.

A notherly route such as taken by the KB in the Dec 7 attack would be possible, but very uncomfortable for the soldiers involved - and so a reduction in combat effectiveness has to be assumed.

However, the main point was that a shipment of that many troops out of the home islands could not be assumed to be just a normal reinforcement of the mandates or Palau. That large a shipment of combat troops would only mean that an invasion was going to happen somewhere. Add that information to all the alerts that had been occurring during the fall of '41 and I cannot see the Japanese achieving anywhere near the level of surprise they achieved on Dec 7 IRL - if they had loaded an Hawaiian invasion prior to the start of war.

Sending all those troops to Palau can only indicate an invasion of the NEI and southern Philippines, which raises the alert level at all pacific installations - or should.

[el cid again]

ORIGINAL: bradfordkay


You talk about the Wake and Johnson Is invasions coming as the first step, which makes sense. However, there is no basis for believing that once those invasions are detected (even if only one day out) that the Japanese could tactically surprise us with an Hawaiian invasion following on the heels of those invasions (strategic surprise, where the 2d Marine Division is still in SD is still possible, though if I had been in charge as soon as I'm told that there's a corps sized Japanese movement with unknown destination afoot I would have had them forwarded to Hawaii).


REPLY: Moving an entire Marine division - one not ready for war - in a hurry is to misunderstand military logistics. The game helps you here - you need to send ships TO San Diego BEFORE you can even start to load them. Then you load them. Then you sail them. Then you unload them. And it takes days to evaluate intel, make a recommendation, get political approval - if you are lucky (otherwise it takes weeks - or you are turned down flat - as Richardson was when he wanted the Fleet to go back to San Francisco). You cannot hard wire this in. I do not think you can get a full scale invasion of Hawaii going up front. But if you are serious, I think you should consider a raid to sieze a lead facility or two. I leave it to players to rule 'too risky' and not send it forward - ONLY send KB forward instead. All you want is a toehold - a point to fly into and sail ships into. You are going to build up for about two months. But it is not bad to start owning even a tiny bit on the other end of the line. It is how I was trained to think. IRL I would favor some sort of recon BEFORE the act - from a sub or agents - to insure the target was still undefended. Like the Japanese - and like the Marines today - I like landing unopposed - organizing - then defending what we took - and flying/sailing in more to back up the lead party. The more detailed the sim, the smaller the lead units will be - makes it cost less if things go wrong and it makes detection harder the less there is to detect.

Putting together a convoy for three divisions invovles substantially more ships than a regular resupply convoy to Truk or Kwajalein. I am of the firm belief that the departure of such a large convoy from Japanese waters would not have gone undetected by US intelligence. They certainly did not miss the invasion convoys headed to Malaya.

REPLY: Surely it does. But that isn't staging out of Truk or Kwaj. It is staging out of Japan itself - in about six components. None of them leave in time to give you any warning - because initial ops are about getting small forward bases - finding the enemy carriers and battleships - and making sure they cannot hurt the invasion groups. They can spend days moving toward the objective area AFTER the war has begun - too late to give you warning. In 1942 form, we did see Kondo's small invasion group - but we could never see the "three divisions" because they had not sailed (yet).