Could the Kriegsmarine IJN neutralize the US War Effort with a combined attack?

[Hunter368]

The coastal area's of the west coast could be patroled to a certein degree using aircraft, smaller armed escorts and whatever DD's could be spared.

Like they did in WW2 vs German subs sinking their ships left and right?

Would the allies take some hits from the IJN subs? Yes.

Agreed

Would it be as crippling as what the KM was doing in the Atlantic? NO!

Agreed, but it is still more damage on top of what KM was doing, which was allot.

Could the IJN sustain operations? NO!

Sustain? No not for years, but for a short while yes. Would it been for long enough to convience USA to make peace with Japan? Maybe.

The fact remains that the IJN had far to many ports and shipping lanes to cover with far to few subs to do it.

They did not need to cover them all, just some key ones. But to me what is more important then how few subs the Japs had or how many ports they had to cover was the fact that USA knew and could intercept all their radio transmissions, thus allowing them to know their where abouts.

And the allies could have used their own subs to counter the IJN subs. Even though our torpedo's didnt work, the IJN didnt know it either.

USA subs would not of been a huge counter to enemy subs IMO. Not like a visible large DD force always with convoys or near ports.

See above

 

[Freebird]

I show 80 DD hulls assigned to the Pacific Fleet. And thats exclusive of the 20 or so that was in the PI and assigned to the Asiatic Fleet.

Syscom most of those DD's are the older "four-stackers" and are not equipped for anti-sub escort or ASW.

The US would not be able to go on major offensive operations in the first half of 1942.

The US had 94 "modern" DD's completed from 1935 {Farraguts} up to and including 21 "Greaves" class in 1941, of which 2 dozen or so are still training working up. Of the older "Flush deck" or "4 stacker" DD's built before 1920, 11 have been modified as ASW escorts, 37 that have been or are undergoing upgrade to Minesweeper/Minelayer, Seaplane Tender or Fast Transport. 14 of the "4-stackers" are in the Far East fleet, and of the other 50 odd "4 stackers", the US Navy does not feel confident to use them for ASW/Fleet operations, as they would just be floating targets. In fact, even while the U-boats were sinking ships right off the US East coast, these DD's were left in port.

Most of the 94 modern DD's + the 11 "flush decks" modified for ASW would be really of much use, not the older DD's nor the Transports/Seaplane tenders/minesweepers. I posted this scenario IF the Japanese had knocked out the US carriers at Pearl, and launched the "third wave" that took out the fuel tanks, the sub base destroyed or damaged the 29 DD's sitting at Pearl. After taking into account 20 - 25 newly launched still working up, + the losses at Pearl you are only left with 60 -70 "modern" destroyers.

If the older "four-stackers" had been any use why do you think they were left in port during "Drumbeat"?

Can you tell me why the ASW actions in the Pacific would be any more effective than in the Atlantic?

A significant failure in US pre-war planning was lack of any ships suitable for convoy escort work.
Despite the urgent need for action, little was done to try to combat the U-boats. The USN was desperately short of specialised anti-submarine vessels. The shortages arose, partly because the massive new naval construction programme had prioritised other types and partly because the destroyers that were available remained inactive in port, even while freighters and tankers were being sunk in coastal waters. At least 25 Atlantic Convoy Escort Command Destroyers had been recalled to the US east coast at the time of the first attacks. At this time there were 13 destroyers idle in New York Harbor, yet still none were employed to deal with the immediate threat, and over the following nights ''U-123'' was presented with a succession of easy targets, most of them burning navigation lamps. At times, U-123 was operating in shallow coastal waters that barely allowed it to conceal itself, let alone evade a depth charge attack.

Despite the massive loss of shipping the US Navy was not able to sink ANY U-boats until April, when it sunk 1, and it sunk 1 more in May. So for the first 6 months of the war they sunk only 2 U-boats.

In fact I would think that the ASW efforts in the Pacific would be much less effective, as most of the DD's equipped for escort/ASW had been transferred to the Atlantic fleet pre-war.

 

[Hunter368]

Agreed

 

[syscom3]

The I-73 was sunk off of Midway on Jan 27 1942, because of intell reports tracking her across the Pacific.

Thats because the IJN were quite chatty. And there is nothing to indicate they would have remained quieter in this scenario. End result is the allies would have a good idea where the subs are and can take actions as appropriate.

And so what if the DD's that were the four stacks with minimal anti-sub gear? The IJN subs didnt know that and would have to deal with them as if they had the gear.

 

[Hunter368]

The I-73 was sunk off of Midway on Jan 27 1942, because of intell reports tracking her across the Pacific.

Thats because the IJN were quite chatty. And there is nothing to indicate they would have remained quieter in this scenario. End result is the allies would have a good idea where the subs are and can take actions as appropriate.

100% agree with you on that one, like I said before. I think that would play a bigger factor then USA old DD would.

And so what if the DD's that were the four stacks with minimal anti-sub gear? The IJN subs didnt know that and would have to deal with them as if they had the gear.

I think you would be right at first, but they would learn quickly that the old 4 stackers were not great ASW DD.

See above

 

[parsifal]

I show 80 DD hulls assigned to the Pacific Fleet. And thats exclusive of the 20 or so that was in the PI and assigned to the Asiatic Fleet.

I think your numbers are about right, however very few of these DDs could be spared for Covoy Escort, because they were needed for fleet support work. Surprisingly, perhaps, fleet DDs are not ideal ASW weapons, particularly in the USN where the emphasis was on fleet support over ASW work. To be effective at ASW, you really need dedicated assets, with the training, experience, teamwork and equipment to do the job. The USN fleet DDs whilst a general ASW capability at the beginning of the war had none of these requisite capabilities. This meant that they were not that good at sinking or even suppressing enemy subs. This was proven on both the east and the west coasts. It was only later, as British developed tactics, systems and training began to be adopted that the US ASW capability began to improve

The coastal area's of the west coast could be patroled to a certein degree using aircraft, smaller armed escorts and whatever DD's could be spared.
I actually have to agree with you there, bu only to a degree. At the beginning of the war 10 IJN Boats were sent to the US West Coast, with a specific mission of trying to intercept the USN reinforcements that were expected to be sent via the Panama canal to the West Coast. this the USN promptly did do, with virtually no loss. The IJN subs did have a secondary role of mercantile tonnage warfare, which was met with very limited success (about four ships, totalling just under 40000 tons. Conversely, despite quite elaborate if thin ASW defences, the Americans did not sink any of the Boats that participated in this offensive



Would the allies take some hits from the IJN subs? Yes. Would it be as crippling as what the KM was doing in the Atlantic? NO! Could the IJN sustain operations? NO!


Can you provide the evidence to support any of these claims? In fact the historical scenario suggests quite the opposite, with regard to the japanese being able to sustain their operational rates, despite the losses. There is nothing to suggest that the loss rates sustaned in 1942, (which if any thing was more dangerous than a straight shipping war) led to any significant lessening of pressure on the US. So I am at a loss to see how you are substantiating these claims

The fact remains that the IJN had far to many ports and shipping lanes to cover with far to few subs to do it.

This is actually a silly argument. The more ports, the more targets, and the thinner the defences, with virtually no disbenefit to the attacking sub forces. Having been trained at the RANs ASW warfare school, during my training, I know of no training manual that would support this argument, and quite a few that would challenge. No wonder the RAN kicks the US backside every time our subs excercise with USN ships, if that the standard of USN ASW doctrine



And the allies could have used their own subs to counter the IJN subs. Even though our torpedo's didnt work, the IJN didnt know it either

Err, yes they did. But I dont see this as a relavant point either way to be honest

I can only reppeat my earlier point, you need to back up your position with some reasonable facts, rather than thump the table like this

 

[Hunter368]

Interesting stuff, parsifal.

 

[syscom3]

The IJN actually had some subs operating off of the west coast in the weeks after Pearl Harbor and their results weren't exactly impressive. Why would that change in your scenario?

As for the DD's, if fleet operations needed to be curtailed for a while so the DD's could concentrate on ASW activities, then so be it. The allied fleet doctrine was not chiseled in stone, and it proved to be quite flexible.

In ASW work, heres the definition of success:
1) Sink the sub outright. Or:
2) Damage the sub so it has to return to port. Or:
3) Disrupt its attack and keep it under water untill the convoy or ship has passed by.
Any type of escort or airplane can perform #2 and #3. As long as the sub doesnt shoot a torpedo at its target, then mission is accomplished. Now think about that when it came to the poorer maneuverability and weaker hulls. The probability of damaging the sub is a lot higher than that of the german subs.

As for the 4 stack DD's not having ASW gear ..... it wouldnt take too long for them to be retrofitted for depth charge racks and some type of sonar. Would that happen overnight? No. Would it be accomplished within a month? Yes. In the meantime, all the four stackers would need to do is to make their presence known and the IJN subs would have to take evasive action.

The IJN was never known for its logistics and fleet train capabilities. Damaged subs needed to go to Japan for most repairs. And because of the vast distances in the Pacific, that means transit times lasting weeks. And those are weeks in which it isnt participating in patrols.

Same with the subs you have patroling off of the Panama Canal and west coast of the US. Look at your transit times between Kwajelein and those locations. it will take them weeks to get on station, and return back.

And finally I have to repeat ...... the IJN didnt have a lot of boats, and the loss of a only few of them would disrupt your plans.

 

[parsifal]

][I]The IJN actually had some subs operating off of the west coast in the weeks after Pearl Harbor and their results weren't exactly impressive. Why would that change in your scenario?[/I]
There were actually 10 Boats, per my previous post, but their primary mission was to attack military targets, with only a secondary priority being given to the merchant shipping. The result was that only 8 steamers steamers totalling 64670 tons (my previous post was in error, as i forgot to add a couple of I-boats to the tally) had been sunk by the end of January.
By contrast, the three groups operating in the far east (groups "Ko", "Otsu" "Hei") with a total of 25 Boats had sunk more than 250000 tons in the same period. In this latter case, the I-Boats in the far east were temporarily given the opportunity to trat MS targets the same priority as naval targets. They were not forced to conserve torpedoes, by ignoring civil targets, in the vain hope that "better" military targets might present themselves at a later date.

So, if the West Coast groups had been given the same flexibility, and had achieved proportionally the same result per Boat, one could have expected the iboats of the US Coast to achieve at least 100000 tons against the US.

As for the DD's, if fleet operations needed to be curtailed for a while so the DD's could concentrate on ASW activities, then so be it. The allied fleet doctrine was not chiseled in stone, and it proved to be quite flexible.

Trouble is, the US DDs could not do this effectively. they werent properly trained for it, did not have the doctrine to carry it out competently, nor did thay have the right equipment to do it. More than anything, adequate ASW is about working in close knot groups, which almost intuitively know how to work together, to try and anticipate what to do next. The USN was sadly lacking this ability unitl the latter part of 1942, after they had been trained to operate in that way by the British. Effective ASW is probably THE most specialized escort activity there is. You just cannot expect to throw a few DDs together, and expect them to operate in anything like a cohesive manner.

In ASW work, heres the definition of success:
1) Sink the sub outright. Or:
2) Damage the sub so it has to return to port. Or:
3) Disrupt its attack and keep it under water untill the convoy or ship has passed by.
Any type of escort or airplane can perform #2 and #3. As long as the sub doesnt shoot a torpedo at its target, then mission is accomplished. Now think about that when it came to the poorer maneuverability and weaker hulls. The probability of damaging the sub is a lot higher than that of the german subs.

I pretty much agree with most of this, except the gunboat type escorts (the PCs and the like) would not have been able to fight effectively against a surfaced Japanese I-Boat, with a 5.5 in gun, and an effective engagement range of over 12000 yds, versus something with a 3 in gun or less, with an effective range of less than 8000 yds. And in terms of top speed, the surfaced I-boat also has the advantage, 24 knots, versus approximately 18 knots. given that the germans favoured the surfaced attack , and we are assuming some form of KM collaboration, it is not unreasonable to assume that the I-Boats might adopt similar tactics.

I dont disagree with your summation of the essentials of ASW warfare. The only problem is that the USN was basically incapable of delivering any of these countermeasures effectively for MS until much later in the year. For example, the US did not even possess any effective aerial depth charge, nor haddit installed any ASV radar(at least to any great extent, and were certainly not proficient in its use to search and attack subs at night), or air launched flares, until later in the year. the reason is because the US had alsmost completely ignored ASW defences as a "defensive measure" that did fit their concept of Mahanian battles that they expected to fight the japanese.

As for the 4 stack DD's not having ASW gear ..... it wouldnt take too long for them to be retrofitted for depth charge racks and some type of sonar. Would that happen overnight? No. Would it be accomplished within a month? Yes. In the meantime, all the four stackers would need to do is to make their presence known and the IJN subs would have to take evasive action.

I dont know whose idea it was to argue that the four stackers were not effective at ASW, but they were, after thay had been modified to carry out the mission, which the british had had to do with their LL four stackers. The only effective conversion would have been what the brits called LR Escort Conversion" which basically ripped out half the boilers, installed LR fuel tanks, advanced sonars and ASW gear, rreducing speed to less than 25 knots, but allowing the DDs to get about 1/3 across the Atlantic (the MOMP). It took some months to put into effect these conversions, until then, the four stackers were not very effective at all. The Japanese would have known that incidentally, as they watched the events in the Atlantic with a very keen interest (thats what makes this argument very weak, the IJN knew about tonnage warfare, but still did not adopt it....)

The IJN was never known for its logistics and fleet train capabilities. Damaged subs needed to go to Japan for most repairs. And because of the vast distances in the Pacific, that means transit times lasting weeks. And those are weeks in which it isnt participating in patrols.

Err, about two weeks actually, plus there was a major base at Kwaj and Truk, which could undertake some repairs to I-boats.

Same with the subs you have patroling off of the Panama Canal and west coast of the US. Look at your transit times between Kwajelein and those locations. it will take them weeks to get on station, and return back.

Yes I agree, except that with most of your DDs providing ASW escort, the job of capturing those advance bases, like Midway (which was developed by the US as a sub base) would have been that much easier. The Japanese, incidentally were better and quicker than the US in moving their Sub fleet bases, because their base facilities were generally located afloat. it was just matter of moving the tender basically, which is a capability glaringly missing in the USN (they had tenders, but not enough of them)

And finally I have to repeat ...... the IJN didnt have a lot of boats, and the loss of a only few of them would disrupt your plans.

Yes, we know that you keep saying that, but you are not providing any evidence in support. I keep pointing out to you that the loss of i-Boats in 1942 had no such effect on the historical operations, so how and why you draw this conclusion is a mystery. Just for the record, in 1939-40, the KM had 51 Boats of which 41 were usuable in the Atlantic, in the first year of operations, they lost 32 Boats, and received just under 30. A nett loss of 2. In that period, the average daily availbility of german U-Boats was just 6, because of the very limited endurance of both the early type VIIs and IXs. Despite this they managed to sink something like 5 million tons of shipping. In the case of the Japanese, they start with about 60 boats, and receive about 20 boats as reinforcement (I havent checked the exact number, but I can if you want), the sink rate by the USN is going to be nowhere near that of the RN in its first year of operations (because even though the RNs defences and training were inadequate, they were far more advanced in 1940 than the USN was in 1942, most importantly because the RN adopted convoy, and knew how to organize them, from their WWI experiences, right from the beginning. The US did not adopt convoy outside of military zones, until mid 1942 (May I believe) There is no reason to suggest or support that a sustained MS campaign is not going to be maintained with the same vigour as either the german campaign, or the Japanese fleet operations of 1942

You need to reveal your sources to more convincingly support your arguments. Your table thumping lecturing technique is only decreasing your credibility i would suggest

 

[Hunter368]

Good information Parifal. Nicely said and done. Very good information and facts.

 

[syscom3]

Parifal, and your sources?

You seem to be making the fatal assumption that the IJN will emulate KM tactics and shipbuilding techniques, using widely optimistic assumptions for the IJN to conduct intense operations several thousand miles from their bases.

And then you widely discount allied countermeasures and make the assumption that the allies will behave exactly as you want them too.

 

[parsifal]

Ive already given you the two sources that I am mostly relying on, plus some idea of my hands on experience.

For the record, I have also already said that I did not think Freebirds hypothetical was all that practical, however, putting that practicality issue aside, I looked at plausible outcomes simply if the japanese swung over to a mercantile strategy, with some help from the KM. . There are no wildly optimistic assumptions, they are merely extrapolations of existing tonnage rates per boat, if the IJN sub fleet had been fully committed to a mercantile strategy. "Wildly optimistic" would be an appropriate label if i was to attempt to argue that the IJN subs could achieve the same tonnage rates as the Germans. I have not attempted to argue any increased production for the IJN, nor have i tried to argue any special invulnerability. its all there, for anyone who cares to look objectively. For the record also, I have also said that I did not think this alternative strategy would be ultimately successful. My objectives are very limited...what would be the effect of a IJN mercantile strategy in 1942-3.

I am simply looking at what happened historically, in the Atlantic, and then extrapolating that if a similar situation was to arise in the Pacific. In the Atlantic, the US countermeasures failed miserably, faced with a far greater threat from the Germans. In the pacific, there are no special circumstances to sugeest that they would operate any differently. In fact there are some issues (like the presence of the powerful japanese surface fleet) that would suggest a far worse allied effort. i would suggest that it is yourself who is making wildly optimistic projections about what might have happened in this scenario, giving the USN capabilities it just did not possess, assuming decisions, like convoy, that are most unlikely to happen, assuming reactions from the japanese that are not borne out historically etc etc

 

[Hunter368]

Agreed

 

[Freebird]

Hi freebird

Your scenario is entirely plausible, however, it is what might be referred to as a "dream run" for the submarine men. If such co-rdination had been attempted, there would have been almost certainly a large amount of planing needed, and if that was needed, a much greater risk of the allies finding out about it. Consider this, until April '42 the IJN JN 25 naval codes were secure, and the IJN submarine codes even moreso, however magic intercepts were routinely being read by the US. In the ETO, the Kriegsmarines enigma codes were finally broken in June 1941. If the co-rdination you are talking about had been attempted, it is almost certain that the alies would have found out about it.

What is far more plausible as a "what if", is if the two axis powers did not co-ordinate their efforts until after PH. This would have required a greater level of co-rdination, and some forceful convincing by the KM submariners, to try and get the intransigent Japanese IGHQ to fully adopt tonnage warfare as the principal means of employment for the IJN subs. IF the IJN subs had been employed in this way, the estimated losses for the USN in the Pacific is in the order of 3.6 million tons. In 1943 it still would be substantial (as evidenced by the IJNs operations in the Indian Ocean), because the convoys in the wide spaces of the Pacific (and Indian oceans) would have required a truly massive ASW effort by the US to protect. It would in my opinion, have extended the war by at least two years, and almost certainly have led to substantial postponements in the Manhatton project. There is no telling the damage this slight alteration in the use of axis resources may have had if adopted. However, I cannot say with certainty that it would have led to the demise of the allied cause, just put a huge dent in it

Ive already given you the two sources that I am mostly relying on, plus some idea of my hands on experience.

For the record, I have also already said that I did not think Freebirds hypothetical was all that practical, however, putting that practicality issue aside, I looked at plausible outcomes simply if the japanese swung over to a mercantile strategy, with some help from the KM. . There are no wildly optimistic assumptions, they are merely extrapolations of existing tonnage rates per boat, if the IJN sub fleet had been fully committed to a mercantile strategy. "Wildly optimistic" would be an appropriate label if i was to attempt to argue that the IJN subs could achieve the same tonnage rates as the Germans.

I am simply looking at what happened historically, in the Atlantic, and then extrapolating that if a similar situation was to arise in the Pacific. In the Atlantic, the US countermeasures failed miserably, faced with a far greater threat from the Germans. In the pacific, there are no special circumstances to sugeest that they would operate any differently. In fact there are some issues (like the presence of the powerful japanese surface fleet) that would suggest a far worse allied effort.

Parsifal what parts of the scenario are "not practical"?

I agree with you that the idea of total joint planning would not work, it would be more along the lines of "separate but parrallel. Germany had been asking the Japanese in 1939 +1940 to joinin the war, but this got a cool reception. Things changed in 1941 with the allied steel oil embargo on Japan.

Now look at it from the viewpoint of the Japanese. The smartest planners in Japan figure out that attacking merchant shipping is the best way to cripple the US war effort. It would be a huge advantage for Japan if the U-boats are attacking US shipping on the US east coast at the same time. However Japan can not plan on Hitler doing anything so stupid as to declare war on the USA. {remember the Axis pact requires German assistance only if Japan is attacked, if the Japanese start hostilities then there is no obligation} I would put forward that it was possible to have 2 separate simultaneous wars - UK USSR vs Germany Italy, while the USA fights only Japan. {perhaps withonly some lend-lease}

Now, Japan approaches Germany with a proposition: Japan will enter the war against USA UK, {which Germany wants} if Germany will also declare on the USA. {Japan was reckless IMO for not asking this, risking having the US concentrate everything on Japan}. Germany would know that Japan was planning to attack the Allies, and roughly when. {They would not know the exact date or about Pearl} The U-boat fleet would thus have a couple of vital months to prepare for drumbeat, and to have U-boats milch cows off the east coast as the time came {perhaps based in Martinique} This way there is not a 5 week delay between "Pearl" and the start of "Drumbeat". There is the possibility that some information may leak out, but it will likely be discarded as disinformation. Remember that the US War Dept. had advance warnings of an impending Japanese attack, yet it was little help if any. The US also has advance warning from the British about the onset of "Drumbeat" yet this did not seem to be of any help.

Japan can also take the time to prepare for war by having a couple of boats on station in all of the important Pacific Indian Ocean ports. The difference between stating the sub offensive right away in Allied harbours compared to several months later is huge. Parsifal have you been to any of the Pacific/Indian ports? I have sailed into Brisbane, Sydney, Melbourne, Hobart, Auckland, Suva, Tonga, Honolulu, and have seen the ports of Portland, San Diego, San Fransico, LA have lots of time spent sailing the Puget sound {Seattle/Tacoma} around Vancouver. It would not be too difficult for a Japanese sub to sneak into one of these ports, which had minimal if any protection {most all ASW had been pulled to the east coast} On the early morning of Pearl the Japanese subs surface in the harbour and start to pick off ships at anchor.

Also I would be interested in your estimation of the possible tonnage per boat probable for the first 2 months of the war. I believe that of the first 5 Drumbeat boats that arrived in mid-January, 80% of the boats sunk an average of 40,000 tons each. {20% were ineffective} This is what was achieved with the USA having 5 weeks to prepare. If they only had a few days preparation it could be more than that. Are you supposing that the Japanese subs could be 1/2 or 2/3 as effective as Germanys? If Germany Japan can deploy 125 subs against Allied ports the Allies could easily lose 2 or 3 million tons a month for the first few months. And we have only been considering the US response to the Japanese sub offensive, what defences would be available in Mombasa, Zanzibar, Durban, Mogadishu, Karachi, Aden, Abadan, Bombay, Calcutta, Madras, Bangalore etc etc? With the British ASW defences already stretched to breaking, I doubt much help if any could be sent. Most of the convoys in this period only went as far as Capetown, if even that far. When it comes right down to it, every Allied hull sunk is another nail in the war effort, regardless of which ocean it is lost in

 

[syscom3]

Freebird, good suggestion for the subs to sneak into the harbor and commence firing in the late morning of Dec 7th.

And I would even credit the IJN (had they done that) to sink a lot of boats. But then, after firing their torpedo's, its time to sail back to Kwajelein for a reload, and the USN would have a month of respite.

But then, theres always the reaction the USN would have after a few weeks, and the west coast would continually get more secure as aircraft and DD's are brought into play.

If there is one thing thats different between the Pacific and Atlantic, is the shear vastness of the ocean, and the Japanese achilles heel of no air recon to find the ships.

Unlike the Atlantic, the Pacific had the vastness for indivdual ships to "dissapear" from the subs. And there is a fundemental difference between the ETO and PTO ..... England needed vast numbers of ships to support its industrial and population base. The US, at a minimum, only needed enough ships to keep Hawaii supplied, and that wasnt a lot of tonnage needed.

So the only way this scenario could unfold on the US west coast is:

1) A surprise sub attack in the harbors, inflicting lots of damage.
2) A drop in tempo of sub activities in the days following as the subs need to reload their torpedo's.
3) A change in the Pacific fleets activities as more emphasis in ASW activities.
4) The IJN subs reappearing off the west coast after 4 weeks, but a greatly increased ASW effort from air and sea assetts.
5) Increasing ineffectiveness on the part of the subs due to sub sinkings, sub damage and countermeasures.

 

[fly boy]

If the Axis had made joint plans for an attack on the USA Allies, involving submarines, commandos and covert operations to begin at the same time as the Pearl Harbour attack, could it have succeeded?

1.) The U-boat war

Some facts to consider, it was not until 5 weeks after "Pearl harbor" that Adm. Donitz's operation "Drumbeat" began with the actions of just 5 five submarines off the US East coast, but these were responsible for huge losses. If the Germans had 25 - 30 boats on station at the time of Pearl Harbor, and the Japanese had stationed most of their 63 available long-range boats on the US West Coast or shipping routes, the Axis should have been able to destroy at least 3 or 4 times as much Allied shipping as they did. The Allies lost over 6 million tons in the first year, even losing double that number would have been devastating.

(Quotes from Wikipedia)


Considering the almost total lack of preparation, and the fact that it took 6 - 10 months for the Allies to respond with Convoys anti-sub measures (the first U-boat on the US East coast was not sunk until April), it's hard to see what would prevent the Axis from wiping out the majority of Allies shipping in the first year

they might have they might have...

 

[parsifal]

Hi Freebird

Parsifal what parts of the scenario are "not practical"?

I agree with you that the idea of total joint planning would not work, it would be more along the lines of "separate but parrallel. Germany had been asking the Japanese in 1939 +1940 to joinin the war, but this got a cool reception. Things changed in 1941 with the allied steel oil embargo on Japan.
The impractical bits is the level of co-ordination needed, plus the starting assumption. The japanese knew about tonnage warfare, but chose not to adopt it. The submarine Admirals in the IJN were constantly recommending that this strategy be adopted, but were consistently ignored or overruled.Its not that IGHQ was immune to the suggestion, its just that they, like the US were totally wedded to the concept of the strategic battle, into which mercantile warfare, the Jeune Ecole concept of naval warfare played no part. The primary job of the submarines was to attrition the US Battlefleet as it advanced across the Pacific to enage the IJN battlefleet. The I-Boats were designed for this specific and specialized purpose, and would have been very good at it IMO. They were extremely long endurance, with high surfaced speeds that would enable them to attack, move to the next position ahead of the advancing US forces, scout with their own onboard aircraft etc etc. of course things didnt work out that way. The Carrier TFs were just too agile for the Japanese to emploiy mobile tactics, so they were reduced to putting up static patrol lines (like everybody else) and hope for the occasional ambush. They had some spectacular successes with that, but nothing like what they had hoped for. And all the while, whilst employed on these fruitless patrol and picket lines, the allied mercahnt men glided lithely by.

The japanese gave glimpses here and there throughout the war as to what their subs could do when employed on shipping attacks, but desire to defeat the USN in open battle, with the Subs supporting the battlefleet always was the paramount objective. if the germans had tried to indoctrinate them, the japanese would have just dismissed it as the ramblings of an inferior naval power. The belief in thewir own style of submarine warfare was very strong in the IJN


Now look at it from the viewpoint of the Japanese. The smartest planners in Japan figure out that attacking merchant shipping is the best way to cripple the US war effort. It would be a huge advantage for Japan if the U-boats are attacking US shipping on the US east coast at the same time. However Japan can not plan on Hitler doing anything so stupid as to declare war on the USA. {remember the Axis pact requires German assistance only if Japan is attacked, if the Japanese start hostilities then there is no obligation} I would put forward that it was possible to have 2 separate simultaneous wars - UK USSR vs Germany Italy, while the USA fights only Japan. {perhaps withonly some lend-lease}


Japanese submariners already knew that, and wanted to employ the submarine force in that way, but the surface admirals just refused to bow to such ideas. However, for the purposes of the scenario, I have supposed that the submarine admirals have won the argument, similar to the way the airmen like genda won the PH strike argument, after Taranto.

[I]Now, Japan approaches Germany with a proposition: Japan will enter the war against USA UK, {which Germany wants} if Germany will also declare on the USA. {Japan was reckless IMO for not asking this, risking having the US concentrate everything on Japan}. Germany would know that Japan was planning to attack the Allies, and roughly when. {They would not know the exact date or about Pearl} The U-boat fleet would thus have a couple of vital months to prepare for drumbeat, and to have U-boats milch cows off the east coast as the time came {perhaps based in Martinique} This way there is not a 5 week delay between "Pearl" and the start of "Drumbeat". There is the possibility that some information may leak out, but it will likely be discarded as disinformation. Remember that the US War Dept. had advance warnings of an impending Japanese attack, yet it was little help if any. The US also has advance warning from the British about the onset of "Drumbeat" yet this did not seem to be of any help.[/[/I]B]
This was pretty much how things did pan out historically, although the Japanese didnt actually tell the germans, the germans knew that something was coming anyway

Japan can also take the time to prepare for war by having a couple of boats on station in all of the important Pacific Indian Ocean ports. The difference between stating the sub offensive right away in Allied harbours compared to several months later is huge. Parsifal have you been to any of the Pacific/Indian ports? I have sailed into Brisbane, Sydney, Melbourne, Hobart, Auckland, Suva, Tonga, Honolulu, and have seen the ports of Portland, San Diego, San Fransico, LA have lots of time spent sailing the Puget sound {Seattle/Tacoma} around Vancouver. It would not be too difficult for a Japanese sub to sneak into one of these ports, which had minimal if any protection {most all ASW had been pulled to the east coast} On the early morning of Pearl the Japanese subs surface in the harbour and start to pick off ships at anchor.


Japanese subs were already on station off the west coast, and in south east asia (as well as around PH), but in the case of the west coast and PH, were given fleet support missions in preference to a purely or primararily mercantile mission. Entering the major ports was not practical. most of the Dutch and CW ports were fully protected by boom defences, which would prevent the entry of the fleet subs. Midget subs might attempt it, but historically the success of these infiltration raids is very limited.

As for the US, I know that PH was protected by boom defences and would probably also apply to most of the major ports in the US (but i dont know). In any event, it would be very difficult to achieve that level of co-ordination for all the ports simultaneously. Best analogy I can think of is 1939 and the Prien raid, This was the only operation that the germans were able to pull off at the outbreak of the European war, so it is difficult to see the IJN doing much better than one or two penatrations. Most of the minor Pacific ports would not have had any shipping in them

The best employment of the big I-Boats would be as corsairs....hunting shipping on the high seas, using their scout planes to locate, perhaps co-rdinating from a command boat. In this way the I-Boats would be used to good effect. Also I would be interested in your estimation of the possible tonnage per boat probable for the first 2 months of the war. I believe that of the first 5 Drumbeat boats that arrived in mid-January, 80% of the boats sunk an average of 40,000 tons each. {20% were ineffective} This is what was achieved with the USA having 5 weeks to prepare. If they only had a few days preparation it could be more than that. Are you supposing that the Japanese subs could be 1/2 or 2/3 as effective as Germanys? If Germany Japan can deploy 125 subs against Allied ports the Allies could easily lose 2 or 3 million tons a month for the first few months. And we have only been considering the US response to the Japanese sub offensive, what defences would be available in Mombasa, Zanzibar, Durban, Mogadishu, Karachi, Aden, Abadan, Bombay, Calcutta, Madras, Bangalore etc etc? With the British ASW defences already stretched to breaking, I doubt much help if any could be sent. Most of the convoys in this period only went as far as Capetown, if even that far. When it comes right down to it, every Allied hull sunk is another nail in the war effort, regardless of which ocean it is lost in

It is difficult to see the japanese being nearly as efficient in attacking defended convoys as the Germans. they have no B-Dienst service, no practidced wolf pack tactics, no centraized command structure, no Carl Doenitz to lead them. On the other hand they are equipped with very high endurance subs, with aircraft built in, and very high surface speeds. These sorts of craft would excel at sinking blockade runners. And this would have been the type of target they would encounter until the end of April. Even against defended convoys, US ASW was so bad until the latter part of 1942 (and probably 1943 in the pacific, that it woud still be quite profitable for them to attack the convoys as well. I dont know exactly how effective, but in the first two months of the war in SE Asia, where less restrictions on MS attacks were placed, the Japanese with 25 Boats on Patrol managed to sink about 250000 tons in about a month of patrolling. thats 10000 tons per month. Now, because of the very great endurance of the Jap sub fleet (about 90 days, compared to about 20 days for a type VII, and about 40 days for a US sub) the operational rate for the IJN sub fleet was always very high. That means that subs operating off the west coast, for example, that at any given time perhaps 1/2 to 2/3 of the available force will be available at any given time. That means that if all 60 boats were used in that way, then at any given time about 35 would be on patrol. If each one is sinking 10000 tons per month, then the IJN fleet is capable of sinking up to 350000 tons per month, or about 4200000 for the entire year. this is a theoretical total, and as convoys and ASW methods were learnt, the loss rate would probably drop, so, at a guess, the IJN sub fleet is probably capable of sinking about 3500000 tons in 1942. Not enough to destroy the US, but enough to cause a significant disruption to her pacific operations.

Hope this is of some help

 

[Freebird]

Parsifal what evidence do you have of boom defences at the time of Pearl? I don't think any of the ports had this {other than Pearl + Manila} as they were not at war in the Pacifc, but perhaps put in place some months later.

I know for a fact that Vancouver did not, as the outer harbour is several miles wide at the entrance. Obviously Moreton bay {Brisbane] would be too big too. How wide is the entrance to Pr. Philip at Melbourne? Puget Sound san Fransico bay are also too big for a boom. Now the inner harbours the Navy docks would probably be protected that way, but the freighters anchored out in the approaches most certainly would not.

From what I have read {and seen personally} things at the other Pacific/Indian ports {Suva, Mombasa, Zanzibar, Noumea, Tonga} are more lax, often times the rules procedures are ignored. {just as the Italian booms at Taranto were not in place}

 

[parsifal]

Incomplete i am afraid. At a gues i would say Singapore, Bombay, Surabaya and probably Calcutta. Likley also Hong Kong.

As far as Australia is concerned, I know that Sydney did, and have to disagree with you by saying also that Melbourne did as well. the Port of Brisbane is a river, at the headwaters of Moreton Bay, a very shallow body of water that any Sub would have to traverse in a surfaced condition for more than 100 miles. The boom defences in Sydney were not completely fullproof however, as the Midget sub attack in May shows,

I still stick to th e theory that attacks into harbours by full sized subs is not practical. Putting aside the harbour defences issue for a moment, which i admit i cant answer completely, IMO subs entering the harbours would not be able to dive, and would be very easy targets in most cases. For the japanese, operating as corsairs, in my opinion, in the open reaches of the ocea, is a far more prudent option

 

[syscom3]

If the IJN began a systematic slaughter of shipping off the west coast, then no doubt, the ships crews would decide not to sail and remain in port "untill something was done".

Losses go down but the war effort is impacted to some degree.

In the long run, anything that happens to be delayed in 1942 becomes irrelevant, after 1943.

The war ends exactly as scheduled on Aug 15th 1945.