Why was the U-boat arm so stagnant?

It was the fall of France that caused the problems for the RN, firstly due to the lack of escorts caused by the invasion scare, ( first happy time) secondly by the improved logistics that bases in France gave to the U boats.Granted they had to learn lessons about the best place to hunt UBoats, but the “failed” tactics the RN used in 1939 Hunter killer groups guided by enigma intercept was the same succsesful tactics used by Hunter killer groups in 1944.

I don't disagree; the hunting groups of 1944 were following the same tactics as they were in 1939. However, they could only be useful once the convoys were sufficiently well escorted to protect them against any subs that leaked past the hunting groups. In 1939 and 1940, the RN didn't really have enough long-range escorts to sufficiently protect convoys from end-to-end, problems which were exacerbated by the invasion scares, by the need to supply ships to the hunting groups (albeit only in 1939), and by the practice of removing ships from convoy escorts to hunt close contacts (within a few hours steaming). The German move to French bases allowed them to reach the exposed convoys in the Mid-Atlantic; these convoys might have been sufficiently escorted for the WWI environment, but were exposed against a wolf-pack. Had the RN been expecting this change in tactics, they would have prioritised construction of ASW vessels prior to 1938.

I'm not sure that actually studying WWI was done that well or deeply and combined with self deception about the likelihood of U boats following prise rules...
Chapter 1 on WWI http://www.ibiblio.org/hyperwar/NHC/NewPDFs/UK/UK, Defeat-of-Enemy-Attack-on-Shipping1939-1945.pdf

This is certainly an older stereotype, but newer scholarship, such as George Franklin's Britain's Anti-Submarine Capability 1919-1939 or D K Brown's Atlantic Escorts : Ships, Weapons and Tactics in World War II, paints a different picture. The need for convoy was well understood - the Shipping Defence Advisory Committee, formed in 1937, drew up an effective convoy plan. The main failings were the misunderstandings about the capability of convoy escorts relative to hunting groups (understandable, given the WWI situation), and a lack of contingency planning for the Fall of France, a problem that was more political in nature. There was likely no real self-deception about U-boats following prize rules - quoting Brown, in respect to an agreement about submarines following prize rules: 'there was little confidence that this would be maintained'.
 
@marathag: Having larger crew is generally a good thing, since it lowers individual fatigue by allowing shorter shifts and helps prevent attrition (via disease, wounds etc.).

But the Type VIIC had the same crew as the far larger 310 foot long,1500 ton US Fleet boats.

When you are limited for the number of crew that could be trained, and the increased ration load from larger crews, might have been better off with US staffing levels
 
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Ramp-Rat

Monthly Donor
At the start of WWII, Germany had a problem, thanks to the strictures of the Versailles treaty, she had been prevented from owning or building submarines. What little work that the Germans had done on building and operating submarines , had had to be done overseas and in secret. When under Hitter the Germans repudiated the treaty, given that the German Navy was a very poor third on the rearmament list. And then tried to build a ‘ balanced ‘ force, with no clear and integrated war plan, what was the war task of the German Fleet prior to the outbreak of WWII. The submarine service had the problem of coming up quickly with a design to be put into production. And so as has already been pointed out picked the best of its WWI designs and updated it, welded not riveted, better engines etc. The tactics of using these submarines had been worked out in exercises with small torpedo boats during the inter war years in the Baltic. Mass surface night attack, from within the convoy, and would for a time prove very difficult to deal with.


However the German Submarine Service started WWII with a number of disadvantages, it was smaller than the British, restricted by geography, and hadn’t truly tested its principal weapon, the torpedo, which had a number of faults. It was only with the surprise success of the Army in France, and the access to the French Atlantic ports, that the U-Boat arm began to be in a position to make a major impact on the war. The need to build up the arm quickly, meant that the rather than try to make a better submarine, all the efforts went in to achieving the number that the high command believed it needed, and training the crews for them. The early success of the U-Boats, lead to a, if it ant broke don’t fix it attitude. So by the time it was broke, it was way too late to fix it. To have had better submarines in service by 42, the Germans would have had to start working on this in 37, and had a clear understanding of what they were going to need. As it was it would be the British who benefited the most from the German war time research post war.


As for the British, they would without the fall of France have had a far easier time of it. And it took time for the fundamental truth of anti submarine warfare to sink in, its not about sinking submarines. It’s the safe and timely arrival of the convoy that matters, that and that alone. Britain could have gone through the entire of WWII, without sinking a single submarine and been in better shape if it had reduced the number of merchant ships sunk by 50%.

RR.
 
Don't forget that Donitz was promised that he would have time to build up the Kriegsmarine until around 1945 in order to properly combat the Allied navies. Obviously, that never came to be.
 
Don't forget that Donitz was promised that he would have time to build up the Kriegsmarine until around 1945 in order to properly combat the Allied navies. Obviously, that never came to be.

Soooo much this. Quite a few people forget that the german navy had been told "not before 44-45", and was very much a navy under construction.
 
The lion's share of the pre-war R&D bugget went into the surface fleet.
Capital ships to be more precise at the expense of destroyer and cruiser development.
 
But the Type VIIC had the same crew as the far larger 310 foot long,1500 ton US Fleet boats.

When you are limited for the number of crew that could be trained, and the increased ration load from larger crews, might have been better off with US staffing levels
You are right as well. One more sometimes overlooked thing is, larger crew in a small boat = high oxygen consumption = lower underwater endurance.
 
German staffing levels:
das-boot-original-movie.jpg


US staffing levels:
OperationPetticoat1.jpg
 
This is certainly an older stereotype, but newer scholarship, such as George Franklin's Britain's Anti-Submarine Capability 1919-1939 or D K Brown's Atlantic Escorts : Ships, Weapons and Tactics in World War II, paints a different picture. The need for convoy was well understood - the Shipping Defence Advisory Committee, formed in 1937, drew up an effective convoy plan. The main failings were the misunderstandings about the capability of convoy escorts relative to hunting groups (understandable, given the WWI situation), and a lack of contingency planning for the Fall of France, a problem that was more political in nature. There was likely no real self-deception about U-boats following prize rules - quoting Brown, in respect to an agreement about submarines following prize rules: 'there was little confidence that this would be maintained'.

The RN had forgotten (actually pulled the Confidential Books and destroyed them) the idea that larger convoys were actually harder to spot as per Rollo Appleyard's calculations in WW1. I think it was 1943 before they had redone the math. Pre-war convoy as a strategy also had to counter 'the bomber will always get through' mantra as politicians were challenging the usefulness of convoy in the face of the air threat.
 

hipper

Banned
P
The RN had forgotten (actually pulled the Confidential Books and destroyed them) the idea that larger convoys were actually harder to spot as per Rollo Appleyard's calculations in WW1. I think it was 1943 before they had redone the math. Pre-war convoy as a strategy also had to counter 'the bomber will always get through' mantra as politicians were challenging the usefulness of convoy in the face of the air threat.

There were other factors at play, larger Convoys mean problems loading and unloading ships and shipping the goods inland especially when London and the East Coast Ports were limited in use.
 
The RN had forgotten (actually pulled the Confidential Books and destroyed them) the idea that larger convoys were actually harder to spot as per Rollo Appleyard's calculations in WW1.

The difficulty with this is that convoys in 1939 were comparable in size to those of WWI, if not larger; convoys in WWI were typically 20-30 ships, in 1939, 30-40 was thought optimal. The first convoys in 1939 were smaller, but this was more down to the immediate lack of merchants in the main convoy ports. The Operational Research Section needed to learn from the battles of 1941-2 before it became clear that even larger convoys were needed. ORS' conclusions were also subtly different from Appleyard's, and were, to some extent, based on different arguments.

Pre-war convoy as a strategy also had to counter 'the bomber will always get through' mantra as politicians were challenging the usefulness of convoy in the face of the air threat.

I've seen little evidence for this; convoy was always well understood as a necessary anti-submarine measure, and little thought was given to air attacks on convoys. The ethos of 'the bomber will always get through' did have a great effect on British ASW, however, as the near-monomanical focus of the RAF on Bomber Command that resulted starved Coastal Command of resources. Without it, Britain might have had the web of effective aircraft ASW patrols she had in WWI.

Wow, talk about turbomorons on display.

Remember these books were part of a 50 volume series covering every technical lesson the RN had learned from WWI, from relatively inconsequential issues like 'Darkening Ship' or 'Height Measurement by Barometer and Thermometer' through to more weighty ones, like 'Fire Control in H.M. Ships' or 'Storage and Handling of Explosives in Warships'. Seven covered convoys, and another five covered more general ASW topics. The books were only removed from general circulation in the late 1930s, following nearly 20 years of exercises based on them. The RN got everything they could from these books, and replaced them with newer concepts, synthesising the lessons they contained with the results of these exercises. It also was not an arbitrary destruction (many copies of the books still exist), they just were no longer widely circulated.
 
And then tried to build a ‘ balanced ‘ force, with no clear and integrated war plan, what was the war task of the German Fleet prior to the outbreak of WWII.
The "balanced fleet" was a direct result of the Anglo-German treaty. It was considered, at the time, the only way for Germany to have any semblance of a Navy; a fleet built around cruisers (heavy/light), submarines and destroyers (and torpedo boats, minelayers, etc.) would (in the opinion of KM staff) be considered a "raiding force" and would've been staunchly opposed by the British.
 
The best protection a boat has, short of the fancy tube-launched autonomous mine containing an MBDA MICA (evidently not available in the time period), is not being seen, and being able to move at a fair clip while underwater. The OKM would've done better to streamline the sail/hull and delete the weaponry for those extra couple or so knots submerged (which would also translate into longer endurance at lower speeds), and fix their shitty schnorkel valve design to stay underwater for as long as possible.

@Slowpoke means THIS.

Mackarel_class_1.png


Also, McPherson mentioned some designs in an older thread, like a creep motor in place of the aft torp tube on the Type VII, and dedicated weather station and radio dispatch buoys (so the sub didn't have to phone home directly and risk getting huff-duffed).

That is an OTL Mackerel modified with a streamlined conning tower case, equipped with the Feretti snort, the DC current creep motors and a direct breather air circuit to the diesel engines as well as a "sneeze box" in the air circuit (also invented by Feretti) to prevent dousing and mitigate pressure slams on the crew as the waves wash over the snort.

The whole problem of what these type boats undergo and what their limits are, become a subject I explore in an alternate time line in an area where one would think snort boats would be most effective. Interesting conclusions I reached. Additional points of departure included effective free swimmer torpedoes from the start, "Atlantic" tactics and earlier introduction of US radars, but these factors are not as significant as I thought the PoDs would be.

1. The deck gun and the AAA does not go away. The boats still spend most of their time on the surface as the snort tech available remains too primitive for extensive underwater cruising. The Electro-boats did not change this aspect of snorting and modern snorting tech still has not to the present. Besides, the "bomb first" ask questions later nature of planes vs. subs means that friendly subs have to watch out for everybody aloft. Hence the AAA will stay, too, in WW II until planes develop standoff weapons that render AAA useless.
2. Cruise radius continues to rely on ye olde diesel oil bunkerage. Depending on whose diesels, hull form and snorts, the endurance of the boat that gets a snort is +/- 5 % changed. Streamlining improves underwater speed, not overall at sea mission/patrol endurance. The real underwater speed and endurance limiter is the battery bank. The modified Mackerel has her SARGOs doubled, but it only adds about 2 hours to 2 days underwater endurance on the charge, depending the drain rate, before she has to recharge (On the snort, whereupon, the ever listening Japanese hear her four times farther away than if she recharged on the surface. A submerged diesel puts a lot of noise into the water.).
3. Snorts, torpedo launch and other masts (periscopes, radar, ESM aerials and the snort extended in the raised position) limit practical underwater speeds (not top theoretical speeds, but practical tactical speeds) to about 5 m/s (18 km/h, 9.7 kn, 11.2 mph). Those remain the modern limits of snort boats, even streamlined ones. Masts bend in the induced current flow at faster speeds. Outer doors still have trouble cycling at high speed. Other problems ensue. (Note the folded fore planes on the Mackerel? There was a reason for that design feature.) By the way, nuke boats have these problems. Until recently...
4. Engineering tradeoffs (costs vs, benefits) have to make sense. So far the Mackerels are not war-gaming out any more efficiently than a well-handled S-boat or Type VII C boat would in the Southwest Pacific Ocean Area which is my Mediterranean stand-in. It remains the (gamed) tactics, deployment strategies and the crews quality factors, who and what make the difference, not the "gimmicks". I would caveat that last remark to add that if one wants to really improve the U-boat arm, then one needs to work on the German torpedoes and not the subs. Solve the problem in the weapon, not the launch platform.
5. And here is another kicker in the pants. Adding a snort to an existing design (GUPPY to Balao) is peacetime expensive, time delaying and in war, not smart, when attrition is in effect and effective hulls into battle is the prime criteria and not production delays or hiccups as one works out the bugs of the new technology. Shermans and Type VIIs are produced long after better designs come off the drawing board and the proving grounds and yards, because something that shoots reliably now is better than something which might or might not work (Panther, M27 or the Type XXI) a half year in the future.
 
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