WI U-boats sink 20% more Allied tonnage in 1941-43

[NORGCO]

Hmmm... how much tonnage was sunk in those years? Need to put this in perspective. (heads off to the book shelves....)

Indeed can we get a solid number on how much was being lost OTL, for those of us who once again find themselves wondering if they wandered in from a parallel reality or are just painfully ignorant?

It is interesting that people on this forum are thinking losing 20% of shipping would be unrealistically high, since the coverage I grew up with - parents who lived through it etc - gave me the impression that ONLY losing 1 in 5 of the ships in any given convoy would be something to celebrate, a lucky convoy with light losses. That the Germans were sinking a greater tonnage of cargo shipping than was being constructed even at full war emergency production was stated as a flat out fact in several different serious documentaries I have seen.

This forum sometimes leaves me feeling seriously embarrassed. This is one example.

 

[alexcoppo]

According to wikipedia articles about SC, HX, CU/UC convoys, most of the convoys were not even attacked.

Using as an example the SC convoys, the most vulnerable to U-Boots, only 20% were attacked and the total losses were about 340 ships, 5% of the total.

With hindsight, I think that the best way to improve U-Boot performance would be to make them capable of finding a convoy.

 

[Tallil2long]

And always followed by posters claiming that the UK would immidietly and effectivly enacts countermeasures that not only nullifies the German actions but also shorten the war with a couple of years

Yeah, some folks need to rethink their outlook. If the Germans do things better it simply doesn't shorten the war. Unless you're just completely wanking the Brits, which seems to be what's happens rather a lot.

Does anyone seriously believe, given how very worried everyone was about the sinking rates at that time, that a 20% greater sinking rate just gives the Allies a glorious opportunity? Seriously. I suspect the guys in charge at the time knew the situation better than any of us armchair quarterbacks, and if they were worried, they had darn good reason. A 20% greater rate would be a catastrophe; I have no doubt it would eventually be overcome, but something big would have to give in the meantime.

I'm pretty sure what would give would be Bomber Command, which devoured a very great share of Britain's total wartime effort (I've seen 25-30% quoted). I think there'd be a tremendous slowdown in bomber production and development, bomb production, sortie numbers, and the tactical and technological development that resulted from the OTL focus and operational tempo.

But the result from all that would mainly be fewer dead German civilians, since postwar surveys showed rather conclusively that Bomber Command's "de-housing" campaign (which comprised the bulk of effort) really didn't cripple Germany's production capacity.

The war would last a bit longer, though, simply because the Germans would have five or so percent greater industrial power through mid-1944 or so, and wouldn't have to divert quite so much effort to defensive measures as early.

 

[The Red]

Like this one. If that fails they always inevitably bring up Anthrax. Or the A-bomb

Whilst I'm sure Plutonium is very sorry to be an inconvenience to the Nazis, the reality is that if Germany is still in a position to put up a fight in August '45 then the bomb's dropping. Maybe not on Berlin mind but that isn't my scenario.

 

[Saphroneth]

Whilst I'm sure Plutonium is very sorry to be an inconvenience to the Nazis, the reality is that if Germany is still in a position to put up a fight in August '45 then the bomb's dropping. Maybe not on Berlin mind but that isn't my scenario.

Don't forget Uranium, either...

 

[BlondieBC]

Sorry to repeat the obvious.
The Germans achieve a 20% increase in the success rates and the enemy does...
nothing. A classic.

I see this sentiment a lot on UK naval issues. What we are analyizing here is a 20% increase in losses AFTER UK counter measures. So lets go through a very rough part of outlining how to get this TL. You have to verify sources to write a TL such as actual % of duds, but it goes like this roughly.


First Pass:

We need 20% more ships sunk. After some research, we figure we need a 33% increase in explosion rates. We look at the dud rates, and see if it works. If not, we then have to go to some additional help such as better operational issues with codes.


Second Pass: We need better men running torpedo program and maybe code rooms. Tinker with some careers. Simply have people test torpedoes.

Third Pass: The only challenge is the person wants a 1941 improvement, not 1939. So we need to time the rise of these better officers carefully. This will be the only hard part.

Forth Pass: Double check we don't have big butterflies.

You can begin writing a highly plausible time line on this topic with a few hours work. This is not some hard POD like changing Hitler belief on jews, it is simply having person Y (who is very diligent in their work) get the job of head tester not person X (OTL person who did not test well). I am probably changing a couple of people careers who are between the rank of LT. Commander and Captain in 1939. Not a biggy.

 

[Deleted member 1487]

Sorry to repeat the obvious.
The Germans achieve a 20% increase in the success rates and the enemy does...
nothing. A classic.

Ironically this statement is equally classic: if the Germans do better than the Allies come up with a counter measure that automatically negates the premise.

By 1943 with covering the mid-Atlantic gap and the building of enough escorts + developing quality enough ASV radar and having enough long range anti-submarine aircraft the Uboats will be dealt with as per OTL; it took time to build all that up and not all of the factories can be shifted to naval work. Sure we can have Bomber Command starved of resources for bombing Germany, but in reality their aircraft couldn't necessarily be used deeply enough into the Atlantic to make a difference there, but they could be used to bomb Uboat pens like IOTL, but to a greater degree; what's the knock on consequence of that? Less experience bombing Germany, which sets back the bomber offensive by potential up to a year or more depending on how much shipping is lost and how many supplies, while the length of the bombing campaign on sub pens will have its own impact.

 

[BlondieBC]

This forum sometimes leaves me feeling seriously embarrassed. This is one example.

Here you go. Great web site.

http://uboat.net/allies/merchants/losses_year.html

PoD is 1941 20%. So let us look at writing a TL. From the perspective of someone who has written a sub TL. It is time consuming to do well, but not hard. I have my previous post, so I have the POD. Lets get closer to what is happening. In late 1940, we improvement, so. We finally fixed our torpedo issues and are rolling out new communication procedures. This thread ask for abrupt jump in sinkings in 1941. We see OTL list of

Jan 58
Feb 54
March 26
April 11

I chose to go up to as follows: I like phase in

Jan 62 (58)
Feb 62 (54)
March 36 (26)
April 26 (11)

It is a small enough boost in ships lost that I could actually write each individual sinking in a TL and not do that much more work than my TL. Probably chose some overall stats plus 3 stories a month for color.

OK, lets outline.

Jan. I need 4 extra ships to come up with. Probably just take 4 of OTL attacks, and have the torpedoes blow up. Might just be one or two convoys. Easy write.

Now to Feb. Need 8 ships. Well, go to 6 hits since now more and more U-boats are carrying the improved X.1 Torpedoes with better warheads. 1 will be effect of some U-boat not lost in Jan and a better crew. One will be our scout planes work better since UK is under bit more pressue.

Now to March. Big drop OTL. To write TL, you have to look up, but probably code break by UK. So we do less effective code break, and this shows how powerful small POD's are. If no code break, then probably should do 50 ships lost, so can put some negative butterflies here. How about some dumb Hitler order.
Now some research on wiki.

The production model 3-rotor bombes contained 36 scramblers arranged in three banks of twelve. Each bank was used for a different wheel order by fitting it with the drums that corresponded to the Enigma rotors being tested. The first bombe was named Victory and was delivered to Bletchley Park on 18 March 1940. The next one, which included the diagonal board, was delivered on 8 August 1940. It was referred to as a spider bombe and was named Agnus Dei which soon became Agnes and then Aggie. The production of British bombes was relatively slow at first, with only five bombes being in use in June 1941, 15 by the year end,[120] 30 by September 1942, 49 by January 1943[121] but eventually 210 at the end of the war.

So we now see why the drop happened. Don't need fix code, just better procedures. So now know after say 30 minutes work that 20% gain in lost ships is TOO small for double POD, so now have to go back to only improved torpedoes. Looking at this data, I can probably Triple UK losses from march 40 until the 4 modified enigma comes out.

Really, people complain it is too much for Germans. It is easy, easy POD. The hard part is my assumption the thread author wants 20% gain each month, not 20% gain over time period listed.

 

[Michele]

Ironically this statement is equally classic: if the Germans do better than the Allies come up with a counter measure that automatically negates the premise.

You are right, and there is a good reason for that.

The Axis was trying to run the war on a shoestring. Any improvement runs face first into that hard reality.

The Allies had ample slack, and therefore wiggling room.

Also, and linked to the point above, the sequence of lucky breaks for the high-risk choices made by Hitler in the run up to the war and in the first years of the same, is probably already a statistical improbability. Trying to get the winning streak even longer and better is pretty hard.

 

[Deleted member 1487]

You are right, and there is a good reason for that.

The Axis was trying to run the war on a shoestring. Any improvement runs face first into that hard reality.

The Allies had ample slack, and therefore wiggling room.

Also, and linked to the point above, the sequence of lucky breaks for the high-risk choices made by Hitler in the run up to the war and in the first years of the same, is probably already a statistical improbability. Trying to get the winning streak even longer and better is pretty hard.

As we have already noted there were a number of simple fixes that would yield major results without any extra resource commitment by the Germans, such as having functioning torpedoes in 1939 or were more diligent with their communications security convoys wouldn't be routed around Uboats on station.

Not every thread dealing with the Germans doing better is a "what if the Nazis had 10000 uboats in 1939!". There is nuance involved and in this particular thread there are very simple and cheap tweeks that would have massive results beyond even what the OP was asking for.

 

[Michele]

As we have already noted there were a number of simple fixes that would yield major results without any extra resource commitment by the Germans, such as having functioning torpedoes in 1939 or were more diligent with their communications security convoys wouldn't be routed around Uboats on station.

Not every thread dealing with the Germans doing better is a "what if the Nazis had 10000 uboats in 1939!". There is nuance involved and in this particular thread there are very simple and cheap tweeks that would have massive results beyond even what the OP was asking for.

Good, the Allies still have more slack.

Note BTW that the lack of reaction after an opposing side's action is always a mistake - even when, say, it's the Allies doing an ATL action and the Axis that doesn't react.
For some reason, however, lots of posters don't want the Allies to do better in an ATL.

 

[Deleted member 1487]

Good, the Allies still have more slack.

Note BTW that the lack of reaction after an opposing side's action is always a mistake - even when, say, it's the Allies doing an ATL action and the Axis that doesn't react.
For some reason, however, lots of posters don't want the Allies to do better in an ATL.

I think lots of posters aren't that familiar with what the Allies could do in return given their massive resources.

Yes the Allies will have more slack by 1944, but in 1942 the shipping resources were stretch to the breaking point and wasn't fully resolved until 1943. Add in 20% or more extra losses and the shipping situation is very dire from 1939-43. Eventually Allied industry is mobilized effectively by 1943 as was finally able to overcome losses, but ITTL assuming things like the signals issue is worked out and there isn't a torpedo problem it would take until 1944 to make up the merchant shipping losses, even with the massive ability of the US shipping industry to churn out new hulls. The Allies have slack, but it took them time to develop that. IOTL 1942 was a tight year and things eased finally in 1943. ITTL with greater shipping losses from 1939 on that tightness in shipping continues well into 1943 and probably to about early 1944, even after the Uboats are effectively dealt with due to the extra sinkings which, if the two issues noted above are dealt with, would in fact exceed the 20% laid out by the OP.

Remember the Allied material advantage too a while to build up; 1943-44 was really the period where that advantage became overwhelming both due to the German head start, but also due to Allied disarmament in the 1920s and early 30s that took a long time to reverse given that the US started really only in about 1939 to lay the new foundations for rearmament and industrial revitalization.

 

[Tallil2long]

You are right, and there is a good reason for that.

The Axis was trying to run the war on a shoestring. Any improvement runs face first into that hard reality.

The Allies had ample slack, and therefore wiggling room.

Also, and linked to the point above, the sequence of lucky breaks for the high-risk choices made by Hitler in the run up to the war and in the first years of the same, is probably already a statistical improbability. Trying to get the winning streak even longer and better is pretty hard.

Actually, I'd have said Britain had very little slack in 41-42, while America's industrial strength (which is what gave the Allies slack) wasn't really mobilized until well after Dec41.

 

[alfredtuomi]

so we are talking about a 20% increase in sinkings which according to one poster are 5% of total ships.this means we are going from an otl rate of 5% to ttl rate of 6%.
not exactly what I would call devastating.

probably the folks most likely to suffer live in India as more shipping is diverted to the north atlantic.

so bomber command has more planes diverted to interdicting subs in the bay of Biscay.and of course the sub pens get bombed while under construction....not after completion.

 

[Tallil2long]

Ironically this statement is equally classic: if the Germans do better than the Allies come up with a counter measure that automatically negates the premise.

By 1943 with covering the mid-Atlantic gap and the building of enough escorts + developing quality enough ASV radar and having enough long range anti-submarine aircraft the Uboats will be dealt with as per OTL; it took time to build all that up and not all of the factories can be shifted to naval work. Sure we can have Bomber Command starved of resources for bombing Germany, but in reality their aircraft couldn't necessarily be used deeply enough into the Atlantic to make a difference there, but they could be used to bomb Uboat pens like IOTL, but to a greater degree; what's the knock on consequence of that? Less experience bombing Germany, which sets back the bomber offensive by potential up to a year or more depending on how much shipping is lost and how many supplies, while the length of the bombing campaign on sub pens will have its own impact.

I dunno. If they built more long-range patrol a/c rather than night bombers... Having, say, twice as many a/c over Biscay and flying over the Approaches would have to have quite an effect. In that respect, depriving Bomber Command will translate directly to effective anti-uboat effort.

 

[Deleted member 1487]

so we are talking about a 20% increase in sinkings which according to one poster are 5% of total ships.this means we are going from an otl rate of 5% to ttl rate of 6%.
not exactly what I would call devastating.

probably the folks most likely to suffer live in India as more shipping is diverted to the north atlantic.

so bomber command has more planes diverted to interdicting subs in the bay of Biscay.and of course the sub pens get bombed while under construction....not after completion.

Bomber Command lacked the resources to hit the sub pens prior to their completion, though there was some harassment during the building process.
https://en.wikipedia.org/wiki/Submarine_pen#The_Allied_bombing_offensive

 

[Deleted member 1487]

I dunno. If they built more long-range patrol a/c rather than night bombers... Having, say, twice as many a/c over Biscay and flying over the Approaches would have to have quite an effect. In that respect, depriving Bomber Command will translate directly to effective anti-uboat effort.

They had pretty much dominated the approaches by December 1941 IOTL and the technology to make aircraft really effective was lacking prior to 1942. By 1942 Biscay was in the process of being shut down and the Western Approaches already largely were; Bomber Command didn't really become a major force until 1942. I'm not saying it wouldn't help in Biscay, but the Approaches were covered largely by the time Bomber Command would have its power siphoned off; of course if you do that they BC is not bombing sub pens from March 1941 on.

 

[Tallil2long]

They had pretty much dominated the approaches by December 1941 IOTL and the technology to make aircraft really effective was lacking prior to 1942. By 1942 Biscay was in the process of being shut down and the Western Approaches already largely were; Bomber Command didn't really become a major force until 1942. I'm not saying it wouldn't help in Biscay, but the Approaches were covered largely by the time Bomber Command would have its power siphoned off; of course if you do that they BC is not bombing sub pens from March 1941 on.

Oh, really? Thanks, I didn't think Biscay was very well covered until '43.

However, I took the POD to imply either more sinkings in early '41 (prior to the Approaches being dominated in Dec), or else the British countermeasures weren't as effective as OTL, in which case more a/c could only have helped. In either case, diverting effort from BC could only have helped -- and the only effort that could safely be diverted was from BC, which was still at that point quite ineffective.

 

[Deleted member 1487]

Oh, really? Thanks, I didn't think Biscay was very well covered until '43.

You're right Biscay wasn't really well covered until 1943, but that wasn't just a function of numbers of aircraft, but also technology to confront Uboats at night and properly spot them with ASV. Without that technology just throwing more aircraft at the problem is less effective than say bombing sub pens or transport to the bases.

http://weaponsandwarfare.com/?p=30092

The RN, RCN, and USN coordinated and systematized convoy planning, added more escort ships, deployed the first true escort carriers, and stretched land-based air cover from every available base using new and longer-range aircraft. Older twin-engine bombers were handed over to Coastal Command and the USN, as four-engine heavy bomber types replaced them in the air war over Germany. A few four-engine aircraft were provided, and more fighters were redeployed from southern England to intercept Kondors and other German aircraft operating out of the Bay of Biscay.

https://en.wikipedia.org/wiki/Short_Sunderland#Operational_history
Sunderlands didn't do well against the Ju88 defenders. It took Mosquitos in large numbers to really make an impact; in the meantime the large four engine bombers were just really coming online in large numbers in 1942, though by then the Short Stirlings were being passed off to Coastal command due to their limited capabilities compared to Halifaxes and Lancasters. Still 1942 is too early to really shut down Biscay as Britain did in 1943-44 for tech reasons.

In a climactic four month period from April to July, 1943, 109 U-boats had been sunk. Many succumbed to aircraft patrolling the Bay of Biscay; others fell to powerful surface Support Groups and increasingly confident and numerous Escort Groups. U-boats sank just two ships in the North Atlantic in August, even as Allied warship strength markedly increased.

Intelligence advances and coups, better air and surface radars, true VLR aircraft patrols, new mid-ocean island air bases in the Azores, more escort carriers with portable air power, and an established and reliable convoy system were the critical components of Allied victory.

 

[Tallil2long]

You're right Biscay wasn't really well covered until 1943, but that wasn't just a function of numbers of aircraft, but also technology to confront Uboats at night and properly spot them with ASV. Without that technology just throwing more aircraft at the problem is less effective than say bombing sub pens or transport to the bases.

http://weaponsandwarfare.com/?p=30092

It might not be safe to assume that much increased focus on anti-submarine a/c would result in more rapid development in anti sub a/c technology, but... Development tends to come faster in the areas of greatest focus.