Change in Japanese Submarine Tactics

During the 1930's several experienced (WWI) U-Boat Captains spend "exchange time" with the Japanese Navy. Additionally, IJN submariner observers go to Germany and take sub rides and time at Doenitz' HQ.

Due to this, while scouting for the fleet has not been removed from the requirements of the submarine force, all subs not required for such duty are to be used for anti-commerce roles. Naturally, if while attacking convoy routes, warships are encountered they are to be the focus of attacks. However when Pearl Harbor is attacked long range Japanese submarines are in place along the US-Hawaii route, and one each just outside Los Angeles and San Francisco. Plans are made to cover the US-Australia route as well. While not true wolf packs, several submarines will set out along a line centered about one that carries an aricraft, which will be used for scouting and finding convoys. Japanese torpedoes, especially because of long range, give attacking submarines a better chance of evading escorts.

With the change in tactics, before the war the IJN converted several large Marus to sub tenders, allwoing greater forward basing abilities on captured islands.

At a minimum this will require more US escort assets to be moved to the Pacific, and will result in greater losses of materiel (and possibily troops) shipped to Hawaii & Australia, as well as the loss of merchant tonnage.

Any thoughts on this? I realize this will require a significant mental shift in IJN submarine operations, but they weren't totally stupid & so the exchanges in the 30's & sub riders on U-Boat patrols 1939-41 might do this.
 
To be fair to the Japanese they didn't expect to be fighting a long war in which a grinding submarine campaign would be a vital component. They were expecting to negotiate for peace in about 12 months from starting the war, much like the Russo-Japanese war. The idea being that once the US main fleet is destroyed then all else will fall into place, and a merchant campaign would be seen as a failure in this scenario.
 

CalBear

Moderator
Donor
Monthly Donor
It would have, to a point, have been a smarter use of IJN resources, but it would have required MUCH more than simply a change in sub tactics.

The Cult of the Decisive Battle was the center of the Imperial Japanese Navy's belief system and had been for close to two generations. Anything that didn't bring that about wasn't worth discussing and no officer who valued his future would even think about a change in that policy while others were present (the Commander who brought a perfectly reasonable convoy plan to the IJN HQ at the start of the war was left out in the cold, with his career destroyed, until 1944 because it required the use of destroyers and a few search planes). The Decisive Battle wasn't just taught at the Academy, it was absorbed through the skin of every IJN officer from the day they swore in. Making that change would be such a huge POD that it would alter the entire Pacific War.

The next problem is that the IJN well, sucked at submarine warfare. They had, hands down, the best submarine torpedo of the war in the Type 95, supurb boats with terrific range and tons of innovations, and they got nearly zero results after 1942. While they had a couple super days in the Solomons, throughout the rest of the war they were pitiful. There were numerous patrols by boats in the Solomons that included over a month ON STATION and resulted in ZERO contacts, similar results were obtained along the California coast. Even as the Americans closed in on Japan, subs were barely a blip, with the only significant success being the sinking of the USS Indianapolis. Despite this remarkable lack of success the IJN sub fleet suffered over 75% losses (83% if you only consider boats completed early enough in the war to actually leave harbor). This is a loss rate equal to the German U-boat force with almost nothing to show for it.
 
How much did the rigid instructions for firing torpedoes (and other stuff I assume) affect the performance of IJN submariners? They had rigid rules about how many torps to fire for each class of target, a battleship or carrier could have a slavo of 6 but a destroyer or merchie could only have one and no follow-up for a miss. Its one thing to lurk in a target rich environment, its another to make sure the only torp you are allowed to fire at a ship is garunteed to hit.
 

burmafrd

Banned
One of the many problems that all the IJ military forces had was the rigid orders and procedures that you HAD to follow. Independent initiative was NOT something that was a career enhancer. In submarine warfare it was shown that you really had to be someone like Sam Harder, Mush Morton, etc to really excell. There was no place in the IJN Subs for captains like that.
Its really hard to see how anything would have been different.
 
thanks for comments

Appreciate all the comments. I agree calBear about the 'decisive battle" mindset, however since subs were at best an auxiliary arm for this there might have been an ability to "experiment" a little under these conditions. Lets hand wave a little and have one japanese boat in the US-Hawaii lane on 12/7/41 have an experienced U-Boat officer on board who gets the skipper to be more flexible with torpedo tactics, with positive results....
 
The next problem is that the IJN well, sucked at submarine warfare. They had, hands down, the best submarine torpedo of the war in the Type 95, supurb boats with terrific range and tons of innovations, and they got nearly zero results after 1942. While they had a couple super days in the Solomons, throughout the rest of the war they were pitiful. There were numerous patrols by boats in the Solomons that included over a month ON STATION and resulted in ZERO contacts, similar results were obtained along the California coast. Even as the Americans closed in on Japan, subs were barely a blip, with the only significant success being the sinking of the USS Indianapolis. Despite this remarkable lack of success the IJN sub fleet suffered over 75% losses (83% if you only consider boats completed early enough in the war to actually leave harbor). This is a loss rate equal to the German U-boat force with almost nothing to show for it.

Why is that? Most Japanese military men, but most especially the officers viewed themselves as modern day samurai. A real samurai stood toe to toe with his enemy, slashing and hacking in a honorable, glorious sword battle. The Decisive Battle strategy fit well with this mindset. True samurai did not lurk in shadows and strike when their enemy was not looking. This smacked of cowardice and treachery and this is how submarine warfare was viewed by the average IJ naval officer. Thus there was little or no enthusiasm for this type of battle. This mindset carried over into other areas such as logistics, supply, and administration, skills that were absolutely vital to running a first class military, but that the Japanese military men at best looked at with utter disdain. Their enemy, however, the Americans, really understood these "lesser" military skills and excelled at them providing their forces with a nearly incalculable advantage.

Without a doubt, an aggressive anti-shipping campaign in the waters between Hawaii and California would have caused tremendous difficulties for the American forces and would have greatly disrupted the war effort, although in my opinion, not decisively. However, for all the reasons that CalBear and I have mentioned the likelyhood of this happening was virtually nil.

There is a strong AH parallel to be drawn here with the U.S. Submarine Force. The Japanese had decent boats (although not enough of them), decent officers and men, and the world's best torpedo from the very start of the war. Yet they utterly failed to make even an impression on the war effort, much less prove to be a decisive factor, mostly due to faulty (or a lack of) doctrine, tactics, training, organization, and enthusiasm. Much has been said by many authors and historians about the U.S. torpedo problems and what might have been if we had good fish at the start. While there are some significant cultural differences in play, I would point to the Japanese experience and my own thread as a guide as to what might have been.

https://www.alternatehistory.com/discussion/showthread.php?t=109950&highlight=torpedo+scandal

Dave

www.pigboats.com
 
Top