The Ship Model Forum

Both the IJN ASW doctrine and the IJN Submarine doctrine were 20 years late in WWII. Both doctrines were still based on the doctrines used in WWI. In other words, the submarine would act as a scout ahead of the main fleets and to engage only enemy warships. This of course was almost taken by the book during the Pacific War and was reflected mostly in all IJN submarine operations other then small campaigns when the IJN submarines were sent specifically to engage Allied sea routes (Indian Ocean, Dutch East Indies). The escort issue reflected the IJN belief that the enemy would not use submarines to attack their merchants therefore little proper-job escorts were in need and therefore little numbers were built until they realised (late already) that the USN submarine force was in fact a major threat to the sea lines.

While I agree with the spectacular record of our US submarine force in the latter half of WWII, I think you should read portions of this book Walt, if you are able to get a copy. "The Japanese Merchant Marine in World War II" by Mark P Parillo.
It's by far the most superb account of the Japanese Merchant Marine in all it's different aspects.
The most important chapters would be Chapter 8 "The Other Silent Service" this covers the IJN ASW effort. If it can be called an effort!
and Chapter 9. "Merchantmen at Sea". This gives an account of the experice of Japanese merchant ships sailing with nearly nothing by way of ASW escort. Or if there was escort, the uselessness of the IJN ASW equipment.

I recommend the whole book, but chapter 9. covers the failure of the IJN to perform ASW and convoy escort. The ability to read japan's codes also made finding targets pretty easy. On the whole I'de say Japan's ASW was 20 years or more behind the Royal Navy's which the German Submarine force had to confront.

On the torpedo question. I find it strange that so many different navies failed to perform the testing programs necessary to determine that their torpedoes functioned up to expectations. One can credit the Japanese for being ready for torpedo warfare at sea. But they failed in every way to prepare to protect their trade.

Bob B.

[quote="Filipe Ramires"]Given that submarine warfare is more my kind of stuff, regarding USN submarine operations and issues early in the war I would recommend you to take a look on Clay Blair Jr. book "Silent Victory". A fairly good book and he speaks a lot of the peacetime tests of the magnetic trigger and its failure during the opening submarine campaign. About tests on the Mark 13 I can't tell much more then I already have.[/quote]

Most early US Submarine victories were with the old Mk 10s that many of the boats carried early on. The problem with the Mk 14s were resolved in mid 1943. The Mk 14 was a great torpedo.. We carried them on our boats as late as the 1980s alongside the Mk 37s and 45s etc.
I have to wonder how many more ships would have been sunk and how many US Submarines would have survived early on in the war if the Mk 14s were up to snuff.. The US Submarine force did recover and was responsible for 70 to 80 % of all Japanese loses..If the MK14 was not reliable then these numbers would have never happened. They literally won the sea war against Japan.

Though being afraid of repeating myself Clay Blair Jr also has two fine volumes on the Atlantic Campaign ([i]Hitler's U-boat War[/i]) and the first one covers in detail the issues with the German torpedo triggers and specially how much they failed in the Norway campaign. Amazing the numbers of targets attacked, some of them even anchored, and the number of hits really achieved. It must have been a true nightmare for any u-boat crew to see that their weapons were not working and so many targets around. Prien was up there in Narvik and fired almost his entire torpedo stock to get zero hits!!! He didn't got back to his base in a very good mood!!!

[quote="Filipe Ramires"]Didn't the first wave of Swordfish, coming from [i]Victorious[/i], chasing [i]Bismarck[/i] and that actually found and attack [i]Sheffield[/i] instead by mistake, had issues with their torpedoes which were armed with magnetic triggers?[/quote]

I believe so. :wave_1: Magnetic pistols were a problem for nearly everyone it seems. Imagine the Norway invasion with perfectly functioning U-Boat torpedos. It could have been a disaster for the RN. I also posted back long ago about the trouble Argentina had in the Falklands war, though that was a problem with on board power, not the torpedo itself.
Still, anyone planning to fight a war would do well to check to see that a system works under actual conditions. Seems few did before WWII :smallsmile:
Bob B.

Didn't the first wave of Swordfish, coming from [i]Victorious[/i], chasing [i]Bismarck[/i] and that actually found and attack [i]Sheffield[/i] instead by mistake, had issues with their torpedoes which were armed with magnetic triggers?

The British sure had some success with air launched torpedoes. I'm not familiar with the air launched torpedo of choice used by the RN and Costal Command. But I'm sure that information lurks in some of the many books I have. At any rate, I don't recall the British being troubled by really bad torpedoes for their String Bags and the collection of aircraft Coastal Command used. An interesting old book is "The Ship Busters, the story of the RAF torpedo bombers" Published 1957.
It's not a complete history, but the story of many of the highlights of RAF torpedo bombing missions.
While the RN had the luxury of not having to put it's torpedo bombers up against any carrier based opposition in the Euopean theater, having their own Carriers gave them the chance to put some important torpedo hits on German and Italian heavy ships. What the RN had was a dive bomber problem, and the RAF Coastal command as well. The large anti shipping campaigns in Europe and the Med. might have experienced earlier successes had a decent dive bomber been on hand.
For the British air launced torpedoes, they needed about 300 years of recovery range to settle down and run at set depth. The pistol armed within that range. The safe range for drop was considered to be over 500 yards range. Still that's pretty close of an approach.

Bob B.

Shoho received multiple torpedo hits, not a single one - one of the rare instances where they worked in 1942. However, the torpedo was as much responsible for the slow attack speeds as the design and age of the aircraft. By 1944, this was largely corrected. Had the torpedo bomber been removed from the inventory, later successes, such as the sinkings of Yamato, Musashi, Zuikaku, Zuiho, Chitose, Chiyoda, Hiyo, Chikuma, Nachi and Kumano (among others) may have been much more difficult, if they happened at all.

Given that submarine warfare is more my kind of stuff, regarding USN submarine operations and issues early in the war I would recommend you to take a look on Clay Blair Jr. book "Silent Victory". A fairly good book and he speaks a lot of the peacetime tests of the magnetic trigger and its failure during the opening submarine campaign. About tests on the Mark 13 I can't tell much more then I already have.

Ah, so different torpedoes, different problems. Funny how no one thought to check the speeds of aircraft in 1941 compared to aircraft in 1930, when the torpedo was developed. Again, something adequate testing would have detected pre-war (lack of peacetime weapons testing is of my pet-peeves, as a vet of weapons systems in the peacetime Navy).

Thanks for that material. I'll keep it in mind. I honestly haven't read anything WWII related in almost two years now as I've been in Civil War mode. My memory must have taken the failures of the two torpedo systems and merged them into one.

Based on Mr. Friedman and Mr. Campbell studies here's a good link to the history of the Mark 13 torpedo carried by torpedo-bombers during WWII. A good statistic is given and the issues of the torpedo are pointed out.

http://www.navweaps.com/Weapons/WTUS_WWII.htm

I have to disagree with you. Everything I've read -- unless new evidence has come up within the past couple of years that I haven't seen -- states that the airborne and sub based torpedoes had exactly the same problems with magnetic detectors and impact pins shearing off with direct hits. Both a direct result of not testing them adequately in the pre-war years. If I'm incorrect I'd love to read some materials that do state the differences in results between the aircraft and sub weapons, though.

Understand that I'm not saying that getting in close wasn't an issue, it definitely was, but HAD they been able to get in close and drop the results would not have been different. I agree that Shoho took one torpedo that exploded, but that doesn't take into account how many hit and did not explode. Direct contact detonations were not unheard of, but they had to be at an angle so that the impact did not shear off the detonator pin.

[quote="Devin"]While tactics can be looked at, it didn't matter if they got to launch position or not. The American torpedoes at the start of WWII were complete failures. Direct hits rarely resulted in an explosion. It took many lost lives in torpedo planes and many frustrating sub patrols with little to show before the problems were worked out (bad magnetic proximity detonators and weak direct-contact firing pins) before American torpedoes would be worth anything in combat. I can't recall when the issue was resolved, but it was well into 1943, maybe even early 1944.[/quote]

Don't confuse the torpedoes used in the torpedo-bombers and those in the subs...they are different types. Submarine torpedoes were plagued by their magnetic triggers therefore so many failures in the first couples of years of submarine campaign. Torpedo-bombers saw action in Coral Sea and Midway but saw little chance of getting even close to drop the "fish". If I recall correctly [i]Shoho[/i] took a torpedo hit at Coral Sea. One of the few effective launches and hit both together made by USN torpedo-bombers during that time. The main issue for the torpedo-bombers remained for quite a while to get close safely to the target and to manage to drop the torpedo. Then somehow someone discovered that dive-bombing was far more effective then torpedoes and pretty much well until early 1944 dive-bombing was preferred to torpedo attack (Midway lesson?).

While tactics can be looked at, it didn't matter if they got to launch position or not. The American torpedoes at the start of WWII were complete failures. Direct hits rarely resulted in an explosion. It took many lost lives in torpedo planes and many frustrating sub patrols with little to show before the problems were worked out (bad magnetic proximity detonators and weak direct-contact firing pins) before American torpedoes would be worth anything in combat. I can't recall when the issue was resolved, but it was well into 1943, maybe even early 1944.

You answered your own question. Ideally torpedo planes and dive bombers should coordinate to prevent the enemy from adopting the optimal defense against either threat. If there was never any US torpedo attacks, the zeros would have been at the proper CAP altitude when the dive bombers appeared, and the decisive dive bombing would probably have been blunted to a substantial degree.

I think the issue was not one of leaving out the torpedo planes, but of realizing that the US types and their weapons were wholly inadequate, i.e. obsolete. Torpedoes were the best way to sink ships, but the TBD was too slow, unmanouevrable and unprotected to undertake this role against a determined defence. Even the TBFs got shot to pieces this time round so it's not as if another plane could have done better immediately. With more fighter support and better coordinated attacks results could have been better, and losses fewer. On the other hand, the Japanese lost their anti-AA formation through the evasive actions they were forced to take, a credible if not so easily noticed achievement.

I have been reading the chapter in Norman Polmar's Aircraft Carriers on the battle of Midway.
It is interesting that none of the torpedo planes scored any hits on the Japanese carriers and that the US forces had many more dive bombers than torpedo planes whereas the Japanese had a 1:1:1 ratio of fighters, torpedo planes and dive bombers.

I was wondering whether the torpedo planes should have been dropped in favour of an all dive bomber force? The torpedo planes did cause the Japanese fighters to drop down to sea level and therefore allow the dive bombers to approach realtively unimpeded.

Also I suppose there was a lot of luck involved as to whether a particular strike group found the enemy.

Thanks,
Roger