WWII IJN navy vs. Allied Shipping

[Christian Lupine]

I am reading Rising Tide by Wier and Boyne. In the book the authors relate the differences in U.S. vs. IJN submarine targeting of shipping. Why did the fail to target Allied shipping until it was too late, while the U.S. targeted Japan's cargo ships? Thanks.

[Unreal John]

I am reading Rising Tide by Wier and Boyne. In the book the authors relate the differences in U.S. vs. IJN submarine targeting of shipping. Why did the fail to target Allied shipping until it was too late, while the U.S. targeted Japan's cargo ships? Thanks.

 

It was a pure doctrinal decision at the highest levels. They thought that submarines would make the best contribution by attriting enemy combat forces as they approached the battle zone. They never seem to have thought of it in terms of "attacking convoys, except the convoys are much faster and better escorted than the transports as well as the high-value targets being more resistant to torpedoes." AFAIK, they never targeted Allied logistics at all; the few transports that were picked off were incidental to other operations.

[Tiornu]

The Japanese war plan anticipated a short campaign, and strategic targets like merchant traffic were irrelevant. There was a short campaign against coastal shipping at the outbreak of the fighting, presumably intended to compound the shock factor of the early naval losses, but that was pretty much it. You can track down a copy of The Japanese Submarine Force and World War II by Boyd and Yoshida.

[Guest aevans]

Let's not forget that US sub doctrine was pretty heavily weighted towards attacking enemy naval vessels until adverse operational circumstances convinced the Pacific Fleet to try commerce raiding as a "temporary" expedient.

[KingSargent]

It was a pure doctrinal decision at the highest levels. They thought that submarines would make the best contribution by attriting enemy combat forces as they approached the battle zone. They never seem to have thought of it in terms of "attacking convoys, except the convoys are much faster and better escorted than the transports as well as the high-value targets being more resistant to torpedoes." AFAIK, they never targeted Allied logistics at all; the few transports that were picked off were incidental to other operations.

Specifically, IJN doctrine called for patrol lines of submarines between enemy bases and the anticipated battle area - ie, the Midway operation had sub lines between Pearl Harbor and Midway. They would have picked up TF16 and TF17 except the MAGIC intelligence enabled the US CVTFs to deploy before the IJN sub patrol lines were on station. In the classic fleet battle scenario the subs would converge on the enemy fleet after it was located and doing as much damage as possible. The USN did the same thing; during Philippine Sea the US sub patrol line sank CVs Taiho and Shokaku besides warning of the approach of Ozawa (the reports were jammed or lost and Spruance was left in the dark).

 

During the Guadalcanal campaign IJN subs deployed between Espiritu Santo and Guadalcanal sank Wasp, Juneau, and Porter and damaged Saratoga and North Carolina.

 

The IJN tried large subs carrying small seaplanes to extend scouting radius. The few minor pinprick attacks (like dropping bombs in Oregon) were basically stunts.

[JOE BRENNAN]

Most IJN sub merchant ship sinkings were in the Indian Ocean. I counted 118 in Rowher "Axis Submarine Successes" v 50 in the Pacific. The Japanese also sent a couple of a merchant raiders there (Hokoku and Aikoku Maru) and their warships and Ryujo's planes (and Ryujo's own guns!) sank a bunch of merchant ships as a adjunct to the carrier raids on Ceylon in April '42, that actually rivalled any convoy battle as quick disaster for Allied merchant ships. The ongoing sub ops were the main 'global war' cooperation between Germany and Japan, along with basing for German subs in Malaya and DEI.

 

The 4 carrier torpedoings by Japanese subs in 1942 loomed pretty large in the carrier balance, key to a Japanese hope for success (negotiated settlement). Unless sea lanes west coast to Hawaii could have been completely cut, it's hard to see how subs could better help achieve the required quick knockout. Boyd&Yoshida argue no subs anywhere else but Hawaii and West Coast from the beginning, which makes sense in hindsight except required foresight the IJN surface and air forces would have things so well in hand in all the areas of conquest. Anyway once a 'decisive fleet action' took shape as at Midway and Guadalcanal, the Japanese pretty much had to commit their subs hoping they'd help score the needed knock blow to the US fleet.

 

Joe

[Tiornu]

Porter

I think you mean O'Brien. Porter was an accidental Blue-on-Blue.

[KingSargent]

I think you mean O'Brien. Porter was an accidental Blue-on-Blue.

Yeah.

[smith]

Most IJN sub merchant ship sinkings were in the Indian Ocean.

 

Right, it was a relatively safe and renumerative hunting ground until well into '44.

 

 

Boyd&Yoshida argue no subs anywhere else but Hawaii and West Coast from the beginning,

 

I read The Japanese submarine force and WWII. I think it's Akahito and Boyd, and they said the big IJM subs should've been deployed along the US west coast for the first 13 months of the war. I'm not sure I agree; some subs were sent there in '42 but accomplished little compared to those in the Indian ocean.

Edited July 10, 2007 by smith

[KingSargent]

Right, it was a relatively safe and renumerative hunting ground until well into '44.

I read The Japanese submarine force and WWII. I think it's Akahito and Boyd, and they said the big IJM subs should've been deployed along the US west coast for the first 13 months of the war. I'm not sure I agree; some subs were sent there in '42 but accomplished little compared to those in the Indian ocean.

The IO subs could base on Singapore which put them a lot closer to targets than Kwajalein, the IJN's Central Pacific sub base, was to the US west coast. "Deploying along the US west coast" would be a bit more difficult than the authors think. The range alone precluded extended offensive patrols; by the time they got to the US coast the subs would have to go home for fuel and stores. There also were not a lot of vital targets along the US west coast. The U-boats could hope to starve the UK of resources and food, the USN DID starve the Japanese of resources and food, but a few subs off the coast are not going to starve California.

[Shortround6]

Starve California no, but 2-3 subs off of Seattle,2-3 off of San Fransico and 2-3 off of Los Angeles/ San Diego might have had an effect on Hawaii.

 

A few mines, a few torpedoings. What would the effect of even 10-12 sinkings along the West Coast have been in Dec-Jan 41-42.

 

No practical difference to starving Hawaii but the number of aircraft, ships, and troops held on the West Coast for anti-sub patrol and coast defence/invasion scare might have made a difference in the spring/ early summer Pacific campaign.

 

Did we run convoys to Hawaii or did ships sail independent?

 

Japanese should get subs out of the area before longer daylight helps aircraft out. A return visit by a few subs in the winter of 1942 might have provided a worthwhile distraction or diversion.

[KingSargent]

Starve California no, but 2-3 subs off of Seattle,2-3 off of San Fransico and 2-3 off of Los Angeles/ San Diego might have had an effect on Hawaii.

 

A few mines, a few torpedoings. What would the effect of even 10-12 sinkings along the West Coast have been in Dec-Jan 41-42.

 

No practical difference to starving Hawaii but the number of aircraft, ships, and troops held on the West Coast for anti-sub patrol and coast defence/invasion scare might have made a difference in the spring/ early summer Pacific campaign.

 

Did we run convoys to Hawaii or did ships sail independent?

 

Japanese should get subs out of the area before longer daylight helps aircraft out. A return visit by a few subs in the winter of 1942 might have provided a worthwhile distraction or diversion.

We ran convoys (pretty well escorted) in 1941-2. Additionally not all Pacific supply came from the west coast. Convoys originating in the East went through the Panama Canal (which was heavily patrolled at both ends) and direct to Samoa and the South Pacific.

 

I'm not sure if the IJN subs could lay mines. Anybody?

 

The Japanese were not interested in strategic diversions unless in support of a major operation. They kept their subs for cooperation with the fleet, and probably got more use out of them that way in 1942 than pin-prick commerce raiding.

[Shortround6]

The idea is more of a "what if" than anything else. the diversion of allied (American) resources would be more important than the actual sinkings.

 

The subs might have had time to return to Japanese bases and still take part in the May-June battles. And no more than 10-12 should have been used anyway.

 

Trying to operate near the American coast in anything but the short winter days would have been way too risky. Even LA winter weather might not have been good to operate in. By the next winter ship and airborne radar would have would have probably made anything more than minelaying way too risky.

[Harold Jones]

I think that the only real benefit that would have come from Japanese subs patrolling the west coast is that it probably would have caused the US to divert assets from the atlantic but while that would have been good for Germany it wouldn't have done much for Japan in the long run.

[JOE BRENNAN]

I read The Japanese submarine force and WWII. I think it's Akahito and Boyd,

That's the book I meant. Co author Akihiko Yoshida's name is written in the book western style, ie. given name Akihiko, family name Yoshida (usually 吉田, ~'Oldfield', a common family name). In Japanese you write it the other way around, and some English language authors, seeking verisimilitude for the period I guess, write the names of Japanese WWII military men family name first, but Japanese almost never write it that way in English now, and some direct translations of Japanese works also write it the western way, so it can be confusing.

 

Re IJN sub minelaying, the 4 old KRS Type subs completed in the late '20's, designated I-[1]21-[1]24 by WWII, were purpose built minelayers, based on the German U-125, UE-II type, handed over after WWI and somewhat parallel and similar to the US Argonaut. They layed several fields of contact mines at the opening of the war, near Singapore, Darwin and in the Philippines. I-[1]24 was sunk near northern Australia in January, the others were retired from active combat [well I-123 was sunk near G'canal but apparently not minelaying]. Per Boyd/Yoshida I-6 also laid a few tube launched German acoustic mines off Brisbane in 1943.

 

Joe

Edited July 10, 2007 by JOE BRENNAN

[Mk 1]

The idea is more of a "what if" than anything else.

No, the idea is not a "what if". It is a historical fact.

 

The Japanese did operate subs off of the West Coast of the U.S. They did torpedo merchant shipping, along the California, Oregon and Washington coasts. One submarine also bombarded (with deck gun) an oil refinery / storage facility along the California coast, and one of the larger float-plane carrying subs launched incindiery bombing raids against the great forrests of the Pacific Northwest (which the U.S. failed to notice at all, until after the war).

 

Trying to operate near the American coast in anything but the short winter days would have been way too risky. Even LA winter weather might not have been good to operate in. By the next winter ship and airborne radar would have would have probably made anything more than minelaying way too risky.

Actually, the Pacific Coast has a lot of ocean off of it. The Japanese submarines did not have much trouble operating in the springtime daylight hours. They even managed to recover aircraft in daylight, a maneuver that left the submarine exposed and vulnerable for a fair bit of time, and provided a homing beacon right to it if anyone managed to spot and follow the returning floatplane.

 

Remember that we are talking about the early war period. It took a fair bit of time for the USN and USAAC/USAAF to spin-up to a level of efficiency in sub-hunting. And particularly, continental defense patrols was generally the pervue of units that were still training-up for overseas deployment, and so were often somewhat ham-fisted when compared to what happened in the active combat zones.

 

I don't have my primary sources at hand (I do have some at home), but I don't recall any of the Japanese subs being intercepted while on station. Lots of reports from US units about attacking subs, but no actual cases (again, as I recall) of the Japanese noticing that they had been intercepted and attacked.

 

the diversion of allied (American) resources would be more important than the actual sinkings.

U.S. forces were diverted to counter the threat. The California National Guard was even stationed along the beaches in anticipation of imminent invasion (at a rate of about one two-guardsmen foxhole per 10 miles of shore, IIRC!).

 

Many USAAC squadrons were retained and operated along the Pacific Coast through the early war years. Patrols of P-39s and B-17s, as well as airships, were apperantly fairly common sights.

 

One needs only look at the ruins of the shore battery positions along the coast to understand that a fair bit of resource was diverted to the task.

 

As an economy-of-force undertaking, I would say that the Japanese sub patrols on the West Coast paid back at a handsome rate of return. Unfortunately for the Japanese, it made not the slightest bit of difference, as the overmatch of total U.S. to Japanese warmaking capacity was so extreme that the resources retained for continental defense had no noticeable affect on the scale of forces that the U.S. would eventually bring to the warzone.

 

-Mark 1

[Tiornu]

one of the larger float-plane carrying subs launched incindiery bombing raids against the great forrests of the Pacific Northwest (which the U.S. failed to notice at all, until after the war).

The Americans noticed at the time but made no military response except to temporarily move a squadron of P-38's.

[Shortround6]

well. I knew the Japanese had contemplated an attack on the Panama canal to the extent of building subs and planes especially for the purpose. Late in the war it's true but it didn't seem like that big a stretch to put early subs off the west coast.

[DesertFox]

Curious, there is the idea of Japanese aircraft from submarines attacking and destroying the locks of the Panama Canal.

 

Was this idea any more than a fool's errand? What kind of defenses were around the canal locks?

[Richard Lindquist]

The US fleet was designed, built, trained, and organized to execute War Plan Orange. The Japanese Fleet was designed, built, trained, and organized to stop WPO by causing attrition to the US fleet as it moved accross the Pacific (by means of air surface, and sub attacks ) so that the two fllets would have a parity of strength when it came time for the "DECISIVE BATTLE". Unfotuantely, the decisive battles were the Phillipine Sea and Leyte Gulf which occurred after the Japanese Fleet was massively attritted in the Solomons and the US war production had come on line big time.

[Ken Estes]

The US fleet was designed, built, trained, and organized to execute War Plan Orange. The Japanese Fleet was designed, built, trained, and organized to stop WPO by causing attrition to the US fleet as it moved accross the Pacific (by means of air surface, and sub attacks ) so that the two fllets would have a parity of strength when it came time for the "DECISIVE BATTLE". Unfotuantely, the decisive battles were the Phillipine Sea and Leyte Gulf which occurred after the Japanese Fleet was massively attritted in the Solomons and the US war production had come on line big time.

We will have to blame it all on A.T. Mahan and his decisive battle construct for the establishment of sea power. The IJN bought it, the USN instead gave Alfred bad fitreps and relegated him to schools and boards after his flag captain tour.

 

One has to admire all the false lessons of war; they seem to outnumber and outlast the [few?] 'right' lessons, be they learned or not. Jutland ought to be considered a curse upon world navies in that regard. One can only admire the dogged determination of the IJN as they devised the diminution theory, made it doctrine and even built ships solely suited for it.... But, as the German Army observed, the Americans do not even follow their own doctrine, remaining chaotic [and successful, until 1950].

[KingSargent]

Curious, there is the idea of Japanese aircraft from submarines attacking and destroying the locks of the Panama Canal.

 

Was this idea any more than a fool's errand? What kind of defenses were around the canal locks?

The Japanese built the 'STO' or I-400 class submarines with a 30,000 mile range and carrying three A/C. At 5223 tons surfaced and 6560 tons submerged, they were the largest submarines in the world. Three were launched, but saw no active service IIRC - they never went to Panama, anyway. The a/c involved were a special design, the Aichi M16A1. They had a theoretical load of one 800kg or two 250kg bombs.

 

Yamamoto came up with the idea (or got credit for it if that is the applicable word). Had the locks been destroyed it would have been worth the effort, but not much chance of that.

 

The Canal Zone was defended by ASW forces (including other subs), groups of Army a/c and USN patrol planes, heavy coastal defence artillery, and heavy and light AA guns. And minefields. The lock gates are massive and intended to resist damage. Anything sunk in the locks could be cleared rapidly.

 

Somehow I doubt that a max of nine a/c with nine 800kg or eighteen 250kg bombs (or some mix) are going to do much damage, even if they manage to make an attack.

[DesertFox]

I guess I get annoyed when they are called super weapons.

 

It was never impossible that some sort of attack against the canal might be made so I figured that they would put in some heavy defenses.

 

Curious, if the Japanese pulled a carrier off of the Pearl Harbor strike and snuck it in to the Canal. Would such an early attack against the Canal have a shot at success?

Edited July 11, 2007 by DesertFox

[KingSargent]

I guess I get annoyed when they are called super weapons.

 

It was never impossible that some sort of attack against the canal might be made so I figured that they would put in some heavy defenses.

 

Curious, if the Japanese pulled a carrier off of the Pearl Harbor strike and snuck it in to the Canal. Would such an early attack against the Canal have a shot at success?

The IJN CVs barely made it to Hawaii and back with the assistance of almost all (if not all) of the IJN's oilers. Getting to Panama - or the US West Coast - was not an option in December 1941.

[Tiornu]

As far as I can tell, Pearl Harbor is closer to the Kuriles than it is to the Panama Canal.