WI Japanese VII Uboats

Because the Japanese used their submarines as auxiliaries to the fleet, not as commerce raiders. It was the way they were used not the quality of the boats or crews that made the Uboats such a threat.
And the numbers, don’t forget the numbers.
 
The Uboats were a serious threat even when Germany only had 50 of them in 1939. My Grandfather was a merchant seaman before the war, but also in the TA. He was called up into the Army straight away and on its next voyage the ship he had been serving on was sunk with all hands.
 
Pacific submarines had pathetic operating depth on both the Japanese and American side. On the higher end it approached a 100 meters, that is 90 on Gato class. Germans could go down to 230 meters. Most submarines would not go down to 90 and stay at that depth for prolonged period of time. Pacific was also clear and calm allowing submarines to be spotted easily by planes even at 100 meters depth.

The Japanese misuse of their own submarines to target capital ships instead of merchants guarantees that no matter what you give them they’ll not make good use of them.
 
Because the Japanese used their submarines as auxiliaries to the fleet, not as commerce raiders. It was the way they were used not the quality of the boats or crews that made the Uboats such a threat.
Pacific submarines had pathetic operating depth on both the Japanese and American side. On the higher end it approached a 100 meters, that is 90 on Gato class. Germans could go down to 230 meters. Most submarines would not go down to 90 and stay at that depth for prolonged period of time. Pacific was also clear and calm allowing submarines to be spotted easily by planes even at 100 meters depth.

The Japanese misuse of their own submarines to target capital ships instead of merchants guarantees that no matter what you give them they’ll not make good use of them.
So if the Japanese use their submarines like the Germans to target merchant ships instead of capital ships they could be a dangerous problem to allies merchant ships in Pacific?
 
AFAIK the Soviet S-class (Stalinets) subs were pretty good for their size.

Good maneuverability, same torpedo tube arrangement as the Type IX, quite fast with good underwater range, better range than the Type VII.
The only significant drawback of the S-class is it's low test depth, which can be attributed to the use of rivets in the pressure hull. A fully welded version of the S-class would have a better test depth.

And it was designed by NV Ingenieurskantoor voor Scheepsbouw, a shell company that was part of the German rearmament effort.
The blueprints for the S-class were given to the USSR in late 1933.

IMO the Germans should have just taken the blueprint of the S-class, modified it slightly and made it into the ITTL Type VII instead of the OTL Type VII. A better sub with a shorter design time because the blueprints were ready in late 1933. Modifications would take about 1 year at most and construction can begin.

The Japanese could have also used the S-class design, I think they would have benefited from it.
Based on the sling carry crawlers that served the battery compartments? Ugh... No. Also, their periscopes and radios were lousy as was their version of Gertrude. Sonar was substandard, too. Torpedoes? Ehhhh... The 53-38 torpedoes were direct copies of the Fiume torpedo (53.3 cm (21") W 270/533.4 x 7.2 "F"). Hull leaked because of shoddy workmanship.

A few reasons exist for why the U-Boat was feared more then a IJN sub,

First off the Atlantic had a LOT more merchant shipping going on. As well as troop transports and such so the pickings were richer.

The Atlantic is smaller so easier to find targets.

GB being an island needs supplies from outside. The Major Alied positions in pacific. Not so much. You are not staving the US or Australia even if you sink 100% of the merchant ships.

The US did not have as strong a navel fleet in the Atlantic (in general)

The US and GB viewed the Atlantic as a defensive war (stop Germany from sinking merchants) but the Pacific was an offensive war.

So it was not the submarines that made the s difference in the reputation but the way the two campaigns were fought
Let us correct that viewpoint.
a. The shipping distribution globally was about 40% Atlantic, 10% Mediterranean, 15% Indian Ocean and 35% Pacific, so that the targets were there. Just who were the targets is a matter of viewpoint.
b. Japanese SLOCs were coastal along the East Asia Continental shelf and among the many straits, and island clusters of the Western Pacific, so convoy routes were just as predictable as the Mediterranean under ASW conditions just as DEADLY as the Mediterranean Sea. Might want to ask British submariners how they liked the Mediterranean or fighting the Italian navy. They did not enjoy it one damned bit. By comparison, until the Atlantic was air covered, the Germans found it a cakewalk.
d. Island garrisons in the Pacific were cut-off and starved by airpower and the barge war. This myth that blockade did not work is kind of one that torques me off. Guadalcanal was one long struggle of who would blockade whom. Japanese submarines and the American fight against them is part of that struggle. The Americans won it.
e. LANTFLT was STRONGER than PACFLT until mid 1943. Part of the reason was the ABC conference decisions about Germany First, Part of it was the Neutrality and later the war convoy escorts in the Western Atlantic. Part of it was to cover the British who had to move Force H replacements to the Indian Ocean to protect the SLOCs to India after Phillips and Somerville FUCKED UP in the Gulf of Thailand and in Sri Lanka respectively and got a large part of the RN sunk or blown out of the water or sent to US yards for repairs.
f. I think the British may have viewed the Battle of the Atlantic as defensive, but once Royal Ingersoll became LANTFLT and took over the American war in of the BOA in the second quarter of 1942, he was determined to hunt the U-boats down and kill them, instead of just beating off convoy attacks. He had to fight that way if American fleets were to power project into European waters. Operations around Iceland and the Azores were offensive in nature. The rewards were TORCH, HUSKY, BAYWATCH, AVALANCHE, NEPTUNE etc.
g. PACFLT meanwhile was fighting for its life to hold Hawaii, the Australian SLOCS, and to cling to Guadalcanal clear into early 1943. That ain't offense. Not until the Central Pacific Offensive in 1943 kicks off in NOVEMBER, can it be said that the war is taken to the Japanese in earnest.
h. Since submarines killed most ships for both sides, it was the submarine that was the naval arm of decision. The Wallies beat the U-boat, the Italians came damn near to making the British regret using subs in the Mediterranean and the American submariners killed about half of the warships sunk by the USN and 2/3 of the Japanese merchant fleet including about 5,000 sampans and barges and Diahatsus in the BARGE WAR.
The problem with turning Japanese submarines loose against the sea lanes was one of capacity. Japan operated a total of 174 submarines in the whole war. The Germans built over 700 Type VIIs alone.
i. It was not that the Japanese did not know how. They operated a small and effective wolfpack off Eastern Australia in the Coral Sea throughout much of 1942 and into 1943. The IJN withdrew their presence once CARTWHEEL revolved into gear and the Australians instituted effective ASW in the Arafura, Timor, and Coral Seas and the Gulf of Carpentaria.

I would argue they had the right idea in using their submarines as high value asset killers and in 1942 they were effective in that role keeping Saratoga out of three of four carrier battles, sinking Wasp in the weeks before Santa Cruz, and making sure Y-Town did not get back to PH after Midway.
j. Fleet doctrine. Too bad that idiots like Takeo, Takagi (Braindead) commanded 6th Fleet during the critical Solomon Islands campaign, is it not?

The problem was that US capacity eventually made itself felt and they pushed them away performing ancillary missions like supplying isolated garrisons, flying reconnaissance planes over South African and US west coast cities (seriously why?), and attacking British shipping in the Indian Ocean.
k. Part of the reason the barge war was important, was that as long as the Americans chopped up all the Daihatsus, Sampans and Junks in western Indonesia and New Guinea(American subs were a major element of this war as well as shore based naval air.), the Japanese had to find some way to move food, fuel, and ammo forward to their starving garrisons. Subs were the only tool that seemed to get through to deliver. Until they did not.
So if you were put in charge (and also as insane as they were) of the Japanese Navy in 1930s you'd recommend they simply copy the American submarine plans?
l. Well, if by insanity, mean apply the American submarine campaign tactics that killed them instead of us? Might have prolonged the war about a year if they had done the staff work and analyzed the PACFLT's weaknesses. For example had they plonked themselves into a TANKER WAR that robs Pearl Harbor and Hawaii of its unmolested sea line of communicationsand starved PACFLT of oil, WATCHTOWER would not have happened, and the Central Pacific might have had to wait until after D-Day in Europe, until enough escorts for convoy were released from European operations.

And the numbers, don’t forget the numbers.
m. That is what made the Germans superficially dangerous. They actually tended to run and vacate critical patches of ocean whenever the ASW got too "tough" for them. They didn't have the guts to hang in there and they by default let the Wallies gradually build up the presence to make contesting sea use eventually impossible. Contrast this with the British in the Mediterranean and the Americans in the East Asian littorals. Never gave up and retreated. Never.

Pacific submarines had pathetic operating depth on both the Japanese and American side. On the higher end it approached a 100 meters, that is 90 on Gato class. Germans could go down to 230 meters. Most submarines would not go down to 90 and stay at that depth for prolonged period of time. Pacific was also clear and calm allowing submarines to be spotted easily by planes even at 100 meters depth.

The Japanese misuse of their own submarines to target capital ships instead of merchants guarantees that no matter what you give them they’ll not make good use of them.
n. If you look at the floor bottom of the East Asian continental shelf and around the Central Pacific and Southwest Pacific island chains where both navies expected to fight, it is very shallow, about 100-200 meters. It made no sense to the IJN who expected to operate there, to build boats that dived deeper than those shallows. The Americans as soon as they could thicken hulls doubled their practical operating depths and produced what could be called "Atlantic Boats". British T-class boats were nominally 90 meter dive boats. They were designed to fight in the Pacific Ocean. It proved to be practical for operations in the Mediterranean to use these "shallow" dive boats. They got SLAUGHTERED.

o. This does not follow from the history of operations of Japanese submarines in Australian waters. Incompetent command decisions and wrong assigned missions accounts for the misuse of the Japanese submarine arm,. (Japanese submarine activities off the Australian coastline ...).

McP.

P.S. Never forget that about 40% of the Battle of the Atlantic Victory belongs to the Canadians, not the British, not the Americans. The RCN never gets due credit for their work.
 
So if the Japanese use their submarines like the Germans to target merchant ships instead of capital ships they could be a dangerous problem to allies merchant ships in Pacific?
It would make them a factor rather than a non factor that they were. But Japanese we’re strapped for resources and oil, and unlike Germans they couldn’t just ignore capital ships. So while more ships would be sunk and more nuisance made I think they’d eventually give up on submarines. They’re not a war winning weapon. Can’t starve a continent into submission.
 
Based on the sling carry crawlers that served the battery compartments? Ugh... No. Also, their periscopes and radios were lousy as was their version of Gertrude. Sonar was substandard, too. Torpedoes? Ehhhh... The 53-38 torpedoes were direct copies of the Fiume torpedo (53.3 cm (21") W 270/533.4 x 7.2 "F"). Hull leaked because of shoddy workmanship.
The sling/trolley/whatever it is was pretty unorthodox but it supposedly gave decreased the height of the battery compartment, freeing space for the crew.

Yes, of course the internals of the S-class are typical Soviet quality, but the basic design was sound.
My point is that the Germans could take this basic design, modify it according to their standards, and start building them ASAP, they would get a better sub than the OTL Type VII.
More range, more maneuverable, high max speed, more underwater range, etc.
And the S-class blueprints were available in 1933, a whole 3 years earlier than the Type VII.
 
You have missed the clues. Battery maintenance in the Stalinets was a mankiller and if HE becomes a crispy critter in the process the boat DIES.

This is the same kind of incompetent unacceptable engineering that killed 10% of all German U-boats and made the Type XXI a crew killer.
 
Last sentence is the key, especially for the Japanese. Even where they were totally on the defensive and lacked the capital ships need to even attempt the "decisive battle" strategy they never turned their boats loose on the vast American supply lines that snaked across a quarter of the planet.
Given that USN is much more proficien in ASW, the much larger size of the Pacific Ocean and the lower density of civilian maritime traffic in the Pacific, any IJN anti SLOC campaign in the Pacific is probably not cost effective.

An anti-SLOC campaign in the Indian Ocean may be worthwhile, but that would give more lee way to USN which is the true enemy of IJN.
 
So if the Japanese use their submarines like the Germans to target merchant ships instead of capital ships they could be a dangerous problem to allies merchant ships in Pacific?
No, USA, unlike UK, can sustain and expand its industry with the resources on the American continent. Blockade would not be too effective against USA.

Simply put, Japan was pretty much doomed once Pearl Harbour is struck. USA simply out resourced, out produced and out built Japan.
 
No, USA, unlike UK, can sustain and expand its industry with the resources on the American continent. Blockade would not be too effective against USA.
It would be more about blockading the United States from its possessions in the Pacific, IMHO. After all, it's not like there was a magic portal allowing them to teleport oil, machinery, and other supplies from the continent to Hawai'i and thence out to everywhere they were fighting; it had to travel by ship. I don't think this would really be terribly effective, but it could certainly impact American operations if they have to take more care with their supply lines.
 

CalBear

Moderator
Donor
Monthly Donor
It would be more about blockading the United States from its possessions in the Pacific, IMHO. After all, it's not like there was a magic portal allowing them to teleport oil, machinery, and other supplies from the continent to Hawai'i and thence out to everywhere they were fighting; it had to travel by ship. I don't think this would really be terribly effective, but it could certainly impact American operations if they have to take more care with their supply lines.
The IJN submarine force had a few spectacular successes (I-19 had arguably the best single attack in the history of warfare, sinking the Wasp, crippling the DD O'Brien with damage that eventually sent her to the bottom months later, and putting one torpedo in the North Carolina, the repairs took her out of the war during the major surface engagements of the Guadalcanal Campaign, five hits with six torpedoes) but it was damaged by the attitude of its commanders. They largely didn't see any merchant ship as a "worthy" target and regularly didn't pursue cargo ships even when contacted, preferring to wait for a warship.
 
It would be more about blockading the United States from its possessions in the Pacific, IMHO. After all, it's not like there was a magic portal allowing them to teleport oil, machinery, and other supplies from the continent to Hawai'i and thence out to everywhere they were fighting; it had to travel by ship. I don't think this would really be terribly effective, but it could certainly impact American operations if they have to take more care with their supply lines.
It would, but the size of the pacific and the larger choice of possiblw routes really make any IJN anti SLOC campaign difficult.
 
What if the Japanese goverment in 1930s build 20+ VII Uboats under license from Germany and have a German military mission train the crews(let's say the Japanese navy see the potential of German Uboats)?how much effect woul Japanese navy having 20+ VII Uboats have on the early years of the pacific war ww2?
Firstly, Japan would need high quality steel and welders to make the boats, an asset already in short supply in Germany.

USN has near universal equipment of destroyers with radar and two years of lessons from the RN fighting U-boats at the start of the Pacific War.

Surface attacks are near suicide against radar equipped ships. Why would you copy such tactics?

The deeper diving is the only asset. USN does not get depth finding sonars till ‘44. It like the RN treated anti-submarine as a 2D problem. As subs dive deeper you need depth finding (3D solution).
to make Hedgehog and Mk9 an effective weapon.
 
Firstly, Japan would need high quality steel and welders to make the boats, an asset already in short supply in Germany.

USN has near universal equipment of destroyers with radar and two years of lessons from the RN fighting U-boats at the start of the Pacific War.

Surface attacks are near suicide against radar equipped ships. Why would you copy such tactics?

The deeper diving is the only asset. USN does not get depth finding sonars till ‘44. It like the RN treated anti-submarine as a 2D problem. As subs dive deeper you need depth finding (3D solution). to make Hedgehog and Mk9 an effective weapon.
1946 and the British ASDIC did not have the capability either until then.

Detecting a submarine with hydrophones was quite difficult, and detecting it with sonar was all but but impossible. Sonar was highly directional. This allowed sonar to get a good bearing on its target, but it also limited the usefulness of sonar for search, since it took several seconds to listen for a return on a single bearing. The sonars of the Pacific War were thus fire control systems rather than search systems, with effective search sonars not becoming available until 1946. Range was also limited, rarely exceeding 3000 yards (2700m) even under the most favorable conditions. Sonar was generally ineffective at speeds over about 10 knots, requiring "sprint and drift" tactics in which the antisubmarine warship had to periodically slow almost to a stop to make best use of its sonar. Sonar could not determine depth with any accuracy and was unable to track a target immediately underneath it. Thus, a submarine could sometimes evade a depth charge attack by maneuvering sharply just as the attacker passed overhead and lost sonar contact. The depth charge explosions themselves blinded sonar, and a submarine that survived a depth charge attack could sometimes break contact behind the "wall" of sonar interference created by the depth charges.

The British developed the "creeping attack" to overcome these deficiencies. One antisubmarine ship would maintain sonar contact with the sub while guiding a second antisubmarine ship that closed in at low speed with its own active sonar turned off. This form of attack was extremely difficult for the submarine to evade.
Until then it was 2 element creep barrage, and BGAG tactics.
 
You missed the entire point about not being able to range gate in search in roiled water, didn't you? Sheesh.

The sonars of the Pacific War were thus fire control systems rather than search systems, with effective search sonars not becoming available until 1946.
 
Last edited:

DougM

Donor
The shear numbers of ships is a false argument. 35 vs 40 is a 1/7th increase or about 14%. Not a minor amount. Second what are we talking about as far as ships go? Then we have the question of how many ships are hoping between small islands close together vs making the US UK run or the run to the USSR.
And then you have the size of the Pacific at about 60m sq miles vs the Atlantic at a bit better then 30. So you have more ships in about half the area. Logic says that you have to cover 2x the area to find the same number if ships.
And don’t forget your subs are not twice as fast or have twice the range.
Add in that it was more common in the Atlantic to have a few destinations relativly close to Germany compared to what you get in the Pacific and you just have an easier job for Germany.
In fact the US had an easier job in the Pacific because Japan was on the inside of the bubble so was easier to find routs and ships.
Frankly with WW2 subs it was a numbers game, X targets in Y area and hunted by Z subs is to one degree or another a matter of numbers.
The same argum we had a while back about trying to better protect the merchant ships in the south Atlantic by arming them or building escorts or what have you. The numbers just become to big a cost for two small a benifit.
 
Top