U=boats vs US subs: an alternative perspective

[lwd]

Depends on the resources involved in building them. Remember Germany was rather resource limited especially before the war. If US style boats mean less boats they might actually be in worse shape.

[tommy303]

As far as fire control goes, US and German subs were comparable, and the power plants of the US subs were not necessarily more advanced than the German--just different. While the US fleet subs did have longer range, higher speeds, and more torpedoes than the type VII, it came at a cost. Fleet subs were very large, slow to manouver under water, and slow diving. In European waters, where an air attack could come at any moment and opposing ASW techniques were highly developed, the type VII was the better of the two boats. this should hardly be surprising considering the US Fleet Sub and the Type VII were built to fulfill different tactical doctrines. The Germans also fielded a number of larger type IX boats which were closer to the US idea of a fleet submarine, but these were more often employed outside of European waters.

All in all, the Type VII design was chosen because it could fulfill the expectations of the U-boat arm in most matters of deployment, numbers, building times and within, as LWD states, the resources allocated to submarine construction in Germany.

[yellowtail3]

As far as fire control goes, US and German subs were comparable,

Hmmmm... I'd been under the impression that the TDC in the fleet boats, with its position keeper and ability to track target position relative to boat & launch torpedoes any any angle - not to mention integration with radar - was substantially better than the Axis equipment. Wiki has an article on it; maybe it is wrong?

...and the power plants of the US subs were not necessarily more advanced than the German--just different. While the US fleet subs did have longer range, higher speeds, and more torpedoes than the type VII, it came at a cost. Fleet subs were very large, slow to manouver under water, and slow diving. In European waters, where an air attack could come at any moment and opposing ASW techniques were highly developed, the type VII was the better of the two boats.

could be. That air prob wasn't real big in 1941, though. And of course, to build fleet boats the Germans would have had to know how (see TDC and all-elec propulsion). Just bigger U-boats may not have been that significant. But for those U-boat COs who liked to unleash five torpedoes at convoys... they'd have done better if they were launching ten at a time, and better aimed (see TDC, again).

[Bgile]

I agree with Tommy ... The US Gato/Balao class submarines and the German type VIIc submarines were each better suited to the type of operations they were required to perform than the one from the other navy. The requirements of the two navies were quite different and the designs reflected that difference.

[tommy303]

I'd been under the impression that the TDC in the fleet boats, with its position keeper and ability to track target position relative to boat & launch torpedoes any any angle - not to mention integration with radar - was substantially better than the Axis equipment

Wiki has been known to be wrong. The German S3 Siemens Torpedo Vorhaltrechner was quite capable of doing everything the USN TDC and position keeper was able to do. Once programed with the proper imputs, the German TDC kept the torpedo programming up to date no matter what manouvers the boat was executing. As to fire at any angle, although this was good in theory, both the US and German navies found that it was advisable not to fire at greater than 30* angle on the bow as in excess of that would overtax the torpedo gyro.

That air prob wasn't real big in 1941, though. And of course, to build fleet boats the Germans would have had to know how (see TDC and all-elec propulsion).

It may not have been a major problem in large areas of the Pacific, but it was a problem in to Uboats operating in the North Sea and Western Approaches to the British Isles, virtually from day one of the war. In this respect, the rapid dive times of the Type VII over the larger boats could make the difference between life and death. As to building a fleet boat, the Germans would have been quite capable of doing so had they so desired. The US fleet boats can trace part of their lineage back to the larger classes of U-boats and U-cruisers the USN acquired as war reparations following WW1. Several of the WW1 U-cruisers had diesel electric propulsion like the US WW2 boats, but the Germans chose to follow a different path using instead one diesel to turn one shaft and electric motor. In this fashion, the E-motor acted as a generator and provided current to run the other E-motor while its diesel was shut down, thus achieving DE drive for cruising. For full power, both diesels were brought on line and clutched to the shafts for direct drive of the props.

The faster speed of the Fleet subs was largely the result of a demand that the boats be used in conjunction with the main battle fleet both for scouting and harrassing the enemy battle fleet prior to a show down engagement. While this was practiced and planned for in prewar exercises, the crippling of the US surface fleet at Pearl Harbour and the subsequent adoption of high speed carrier task forces as the main striking arm left the Fleet Subs without their preceived mission. Their long range and huge torpedo armament did allow them to slide into a role of interdicting Japanese shipping in the far flung corners of the Empire and this played a pivotal role in the winning of the war in the Pacific.

The smaller Type VII would have been of much less utility in the Pacific, but at the same time, the huge fleet subs would have been unsuitable for service in European waters for reasons already mentioned--poor manouverability and slow diving times.

Another often forgotten aspect was the Anglo-German Naval Treaty which allowed the Kriegsmarine to build up a submarine force based on a percentage of the total submarine tonnage possessed by the British Empire and its dominions:

In the matter of submarines, however, Germany, while not exceeding the ratio of 35:100 in respect of total tonnage, shall have the right to possess a submarine tonnage equal to the total submarine tonnage possessed by the Members of the British Commonwealth of Nations. The German Government, however, undertake that, except in the circumstances indicated in the immediately following sentence, Germany's submarine tonnage shall not exceed 45 per cent. of the total of that possessed by the Members of the British Commonwealth of Nations. The German Government reserve the right, in the event of a situation arising, which in their opinion, makes it necessary for Germany to avail herself of her right to a percentage of submarine tonnage exceeding the 45 per cent. above mentioned, to give notice this effect to His Majesty's Government in the United Kingdom, and agree that the matter shall be the subject of friendly discussion before the German Government exercise that right.

This in effect meant building a few very large Fleet type submarines, or many smaller medium sized submarines. For the anti-shipping campaign visualized by Doenitz, the choice of the smaller Type VII was obvious.

[yellowtail3]

now THAT was an informative post; thanks!

[Karl Heidenreich]

I have always wondered what would have happened if Doenitz, and not Raeder, would have dictated naval policy in Germany before the war and the behemoth resources used in the Twins and the Bismarck Class Battleships were used in a bigger U Boat force. I have never considered better ("I think we need a bigger boat" - Chief Brody from Jaws) subs than the Type VII, just more of them.

By 1940 those small and ill suited Type VII were closing to grasp the victory. Some 50 or 70 more Types VII in the Atlantic in addition to those already deployed could have turned History around. Now, if we follow yellowtail suggestion, still using the resources wasted in the surface fleet... the consequences could have been devastating.

Best regards,

[RF]

But that in turn Karl, poses the necessity of more robust and desparate British responses, plus greater help from the US who would certainly regard a more effective U-boat force as a threat to US Atlantic security and to the US fleet. I would think it more likely that a more numerous U-boat force would mean more attacks on neutral US ships, even cases of accidental attack caused by mistaken identity. I think that could well mean US declaration of war on Germany, caused by a provoked US public opinion, well before Japan attacked Pearl Harbor. As evidence in support of this I woulds cite Brazil's declaration of war in August 1942, after five of its merchant ships were sunk by U-boats in one day.
Another aspect is that if the US is drawn in to declare war on Germany on the same basis as in WW1, then less US attention is focussed on the events in China and Indo-China, so Japanese moves do not meet the same degree of US hostility. If this means no US trade embargoes then there is less pressing need for Japan to attack the US. If Germany is heavily engaged against the US as well as Britain and the USSR in the Autumn of 1941, then it maybe that Konoye remains Japanese PM instead of Tojo replacing him, and a more opportunist Japanese government waits upon events in Europe before moving in on Malaya and the East Indies. If there is no threat to Japan's imports of oil and strategic materials, then it is likely that the IJA would be tasked with finishing and winning the war in China. Germany faces the US/Britain/USSR alone, and the full US shipbuilding capacity is brought into play against the U-Boats.

[RF]

I agree with Tommy ... The US Gato/Balao class submarines and the German type VIIc submarines were each better suited to the type of operations they were required to perform than the one from the other navy. The requirements of the two navies were quite different and the designs reflected that difference.

Now if the Japanese had noted how the British were tackling the U-boats (particulary as they had full diplomatic representation in Britain until December 1941, including naval attache) they could have given their convoys more air protection, possibly by using flying boats, and using air attack on surfaced US subs. They could also have learned how the British used radar, not just at sea but in the Battle of Britain, and developed their own radar much faster and so more easily locate US subs on the surface. Presumably this enhanced Japanese reaction to US sub attack would then start to place US subs at a tactical disadvantage and increase their losses and reduce Japanese shipping losses?
Now the question that comes to my mind is that the implication is that the Japanese now have more shipping and naval forces for the battles of 1944 and 1945 - so it would be likely that US losses in the Philippines would be much greater, possibly so much that the Iwo Jima and Okinawa landings don't happen. That in turn makes the dropping of the atom bomb a far more difficult operation......

[mike1880]

The loss numbers suggest the Japanese were fairly competent at sinking submarines, where they failed was in preventing the submarines from sinking merchant ships. Their biggest failing was the use of very small convoys.

Mike

[hammy]

There is a bit of a myth nowadays that Japan took no very effective steps to counter the Allied submarine offensive , particularly in regard to protecting its merchant shipping .
If you study the combat vessel types constructed , building and planned by the IJN however you see that an extensive series of escorts were produced of the corvette and frigate types , and by the war's end these were honed down designs for mass construction , being churned out at a high rate .

"Warships of the IJN 1869 to 1945 " by HansGeorg Jentshura , Dieter Jung , Peter Mickel , ISBN 1-85409-525-0 has comprehensive listings of all hulls and drawings for each vessel type . ( As an aside , the book gives good details and drawings for all the planned post WW1 behemoths that got stopped by the Washington treaty , too )

Japan also had specialised aircraft designed for ASW operations , used Magnetic Anomaly Detection devices to detect submarines from the air , and pioneered air-escort techniques .

I think that the short duration of the Pacific war -- 1942 , 1943 , 1944 and half of 1945 , say forty months , together with the terrific attrition rate of anything Japanese that was afloat during the last year , has tended to support the illusion that little or nothing was being done .

Churchill's dictum in regard to War equipment provision " In the first year , nothing ; in the second year , a trickle ; in the third year , all you want " , is especially true of minor warships , and you see the same situation in the Battle of the Atlantic , where in 1939/40 those ships that are organised into Convoys are escorted only out of the Western Approaches and usually by an AMC , with a couple of corvettes and destroyers along if you were lucky .
From late 1940 and through 1941 into 1942 , the escort forces gradually get stronger ,and travel further with their charges , but it is really only in mid 1942 - say 30 months from the start of the war - that the emergency programmes of escort construction start to bear real fruit and the first efficient escorts , the River class Frigates and the modified Black Swan class sloops , start to routinely appear in effective numbers in the escorts , to back up the Corvettes and Destroyer-Escort conversions ( and all the other miscellany of more or less suitable vessels ) that had carried the strain until then .
As it was the Allies who held air superiority to an increasing degree in both the Atlantic and the Pacific theatres , It was the Allied submarines which won in the Pacific , and the Allied Trade Protection forces which won in the Atlantic .

To a great extent the different forms the WW2 submarines appear in , and their deployment and "success" in action is very much to do with the role the various navies intended them to play , and the tactical doctrine that was being put into practice by their crews , as directed by the Submarine commands .

[lwd]

... Their biggest failing was the use of very small convoys.

Did they have any other choice? The larger the convoy the more inefficient it is particularly when you have a lot of places you need to send ships and the Japanese were short on shipping as it was.

[RF]

lwd makes a valid point here, and there is still the stark contrast in the effectiveness of Allied countermeasures compared with the Japanese. Also the Japanese fell behind in the technology of the weapons deployed against submarines, such as submarine torpedoes, sonar buoys which were deployed against Jap subs in the Atlantic. Compare that to the diligence shown by the Japs on protecting their allies ships in the Far East, such as the hilfskreuzer Michel.

[Bgile]

I've read elsewhere that escorting merchants wasn't considered particularly career enhancing in the Bushido code. It wasn't really a task befitting a true warrior, and likewise attacking them which is one reason they didn't conduct submarine warfare against allied merchant traffic to any great degree. They mostly tried to use their submarines against warships.

[mike1880]

The larger the convoy the more inefficient it is particularly when you have a lot of places you need to send ships and the Japanese were short on shipping as it was.

I expect there's a degree of truth in that, but the shortage was exacerbated by the actions of both army and navy. With more efficient shipping management I would think they could probably afford a little inefficiency in unloading.

Mike