AHC: Best possible German performance in the Battle of the Atlantic

Good question. The North Atlantic is huge @ 15 million nm^2, but of course it doesn't have to be searched in its entirety. GIUK gap appears to be 1200nm from UK to Greenland and the width would be the expected daily raider travel should be 24 hours x 15-20 knots or up to 360-480nm x 1200nm or around 1/2 million nm^2. North of that the Artic Sea is about 3 million nm^2 and the Norwegian Sea and Barents Straits combined are a million nm^2.

KM knew the basic North Atlantic convoy routes by late 1941 and that looks like total 2-3 million nm^2 sea area to be swept. A 6 hour air patrol could average 5000-18000 nm^2 search depending how bad the weather is, while radar patrol plane searching for a convoy should manage to sweep 36-48,000nm^2 per air patrol . To get 100% coverage of all these routes would need ~60 radar patrol planes per day. But that only covers 1/4 of the day, so 100% coverage over 24 hours is more like 250 sortie per day. As a sustained effort- over months- that could require an effort of about 1700 sortie a week . With squadrons flying twice a week that's a force of maybe 850 planes? To keep a fleet of 850 patrol planes flying that much- should require a production of something like 1500-2000 planes per year.

All that is -Radar/weather/fuel permitting.
 
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How many days to cross the gap for the convoys? Guess they wont have to be located at random 4 times each day?
IIRC, the gap was about 2,000 miles in 1941, so about 40-50% of the journey would be without air cover. I imagine that once a convoy is located, the priority will go to tracking them rather than searching more ocean for ships.

Also, how far out could the German AC patrol? if they're using the Bv 138 flying boat, maybe they could even refuel from Milchkuh U-boats and locate convoys before they reach the gap
 
IIRC, the gap was about 2,000 miles in 1941, so about 40-50% of the journey would be without air cover. I imagine that once a convoy is located, the priority will go to tracking them rather than searching more ocean for ships.

Also, how far out could the German AC patrol? if they're using the Bv 138 flying boat, maybe they could even refuel from Milchkuh U-boats and locate convoys before they reach the gap
So at 250 miles per day (12 knots), its 8 days to cross. So the Numbers could be divided by 16 (8x2 (2 because they cant patrol at night) and then add some for tracking. I’m exaggerating because they want to locate the convoys in the western or eastern Half but maybe 200 aircraft (sustained).
 

Ian_W

Banned
People need to remember that the RN does not, in fact, drink lead paint.

If you just want it to be a worthless Kreigsmarine wank, then ok.

But you should all remember the RN implemented the Hurricat as a MPA counter by May 1941, and it worked.

If there is a greater German investment in MPA, then there will be a corresponding RN investment in Trade Protection Carriers and CAM ships.
 
Probably not as there would be alot of stowing away and stuffing around to carry out flight ops. Your pilots still need to maintain proficiency aswell. Most raiders carried aircraft. Merchant captains weren't always the sharpest, one seaplane flew over a ship and dropped a message to go to a map reference. The captain obliged and the ship was captured. The plane even had German markings on it!
I think you're conflating two stories.

Firstly the the capture of the Wairuna at Sunday Island in WW1 by the raider Wolf. The seaplane dropped a message demanding the ship's surrender and also a bomb.
Steer towards German cruiser, and do not use your wireless. If you do not obey this order your bridge will be bombed and your ship shelled by German cruiser.
The master complied and the ship was taken as a prize.

In WW2 a seaplane operating from the raider Pinguin (in RAF markings) dropped a message onto the deck of a tanker (the Filefjell) directing her to:
Alter course to 180° distance 140 miles on account of vicinity of enemy raider.
From that point take up cours [sic] direct to 31°N 37°E thence you get further informations [sic].
Do not use wireless.
The Norwegian captain (Nordby) of the Filefjell appeared to obey these orders but later was found trying to escape at top speed (he'd become suspicious, especially at the poor English) and the seaplane was relaunched, guided in darkness by RDF on a raider warning being sent by Nordby. When it found the tanker again it ripped away her radio aerials (by means of a dangling grapnel) and strafed her bridge with cannon and machine gun fire before setting down (almost out of fuel). Then the tanker was ordered to show her navigation lights and
Remain stopping [sic] here. cruiser Cumberland will go with you.
The tanker complied (perhaps because it was a huge floating bomb, loaded with ten thousand tonnes of aviation spirit. It was captured as a prize (with code books and papers intact) and fuel oil offloaded to the Pinguin.
 
The smart mine part is correct. Submarines lived on the surface except for the final attacks and evading ASW forces. It is better to compare the cruising surface speeds of subs to the cruising speeds of ships. And here is where we see a big part of the reason submarines are much better at finding merchant ships that might well be moving at 10 knots or so compared to warships that are probably going closer to twice that speed.
Submersible torpedo boats in my preferred description.
 
People need to remember that the RN does not, in fact, drink lead paint.

If you just want it to be a worthless Kreigsmarine wank, then ok.

But you should all remember the RN implemented the Hurricat as a MPA counter by May 1941, and it worked.

If there is a greater German investment in MPA, then there will be a corresponding RN investment in Trade Protection Carriers and CAM ships.
Not disagreeing with that. “Sustained” might in fact mean unsustainable. I’m aware of that. But it would be one more component necessitating a rapid response and causing allied shipping losses until the allied response is effective.
Germany would need more than that trick to turn things around.
 
Merchant Shipping Losses 1939-41.png
 
What I find interesting from the losses table is

1) The big losses due to aircraft in March - May 41. Assume this is due to Greece campaign and might include Greek and Yugoslav losses which sort of pad the total. Same with May June 1940, evacuation of France. Otherwise the losses are sort of unimpressive during the non evacuation times.

2) The losses to warships are low. Which we all knew, but it reinforces it was kind of dumb to risk Sharn+Geis+Bismarck against what was achieved, vs the fleet in being value of all the ships in the Baltic. Once the Italians are in, and the med is an active theater "fleet in being" matters.

3) E-boats, cool and all, but their anti shipping mission produces lame results, probably more useful if railed to the med or black sea
 
People need to remember that the RN does not, in fact, drink lead paint.

If you just want it to be a worthless Kreigsmarine wank, then ok.

But you should all remember the RN implemented the Hurricat as a MPA counter by May 1941, and it worked.

If there is a greater German investment in MPA, then there will be a corresponding RN investment in Trade Protection Carriers and CAM ships.



This is a thread about 'maximising the performance of Germans in the battle of the Atlantic'....not the RN!


worthless Kreigsmarine wank
starting a flame war?

No one is forcing you to read the thread or post.
 
So at 250 miles per day (12 knots), its 8 days to cross. So the Numbers could be divided by 16 (8x2 (2 because they cant patrol at night) and then add some for tracking. I’m exaggerating because they want to locate the convoys in the western or eastern Half but maybe 200 aircraft (sustained).

Most convoy speeds were 7.5 knots early in the war and 9 knots later in the war. Usually light is 2/3 to 3/4 day light and the rest night. Patrols can be conducted at night provided its a moonlit night with little clouds....just like day time patrol in cloudy/rainy weather. With a sustained force of 200 none-radar patrols per day that's roughly;

200kts x 20nm sweep x 6 hours = 4000nm^2 per daylight hour times two hundred sortie. That's 3/4 million nm^2 swept per day.
 
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Ian_W

Banned
This is a thread about 'maximising the performance of Germans in the battle of the Atlantic'....not the RN!

Well, that's your first lie. Go read the thread title again.

You'll find the word 'possible'.

If you want to make a wank-fest, then I'll start feeding the Alien Space Bats, as their assistance will certainly help.

PS There is a hint in your sentence what could have made life more difficult for the Allies.
 
Well, that's your first lie. Go read the thread title again.

You'll find the word 'possible'.

If you want to make a wank-fest, then I'll start feeding the Alien Space Bats, as their assistance will certainly help.

PS There is a hint in your sentence what could have made life more difficult for the Allies.

then you will be added to the 'ignore list'.
 
The production issue is not JUST building subs but training crews, each vessel needs a navigator, does not matter if its a sub or a BB, more navigators you need more training billets. U boat net gives good picture of the training regime. Its not pretty.

Pre war Germany cannot count on bases in Norway or the Atlantic coat of France so any LRMP pre war has to transit from Germany across an enemy country or by such a circuitous route it has no time on station. Its a non starter. And Pre war there is no active hostility from Italy and the MN to consider. Apart from pre war positioning any AMC has to transit past the RN to get to an operational area.

Once you get Norway and France that changes, and Germany did prioritise the aero naval war, and look what it got them. ( arguably not doing this but immediately prioritising Russia is a better bet but both are actually long odds).

In terms of the course of the war there are distinct phases and seasonality. The North Atlantic in winter is a bad place for Mk1 Eyeball which in the end is what a sub depends on so activity will decrease over the winter months - although convoy sailing will continue. Away from the North Atlantic the target are easier but time on station limited and the targets themselves much less lucrative.

So 39/40 attempted close blockade fails because of the density of escorts and air cover.

41 is acting in the open Atlantic, but in fact hitting by and large older slower ships not in convoy. ( its not until September 42 that attacks on convoys exceed attacks on unescorted ships). Meanwhile the replacements are newer faster ships - faster than a U boat so getting ahead of the convoy - which is itself changing course is paramount, I will come back to sept 42. But during the course of 41 the US is increasingly involved in convoy escort work in the end covering convoys until they are in range of land based air.

Again during the course of 41 as escort production increases the boats increasingly disperse to peripheral areas to avoid attacking convoys.

42 they have a gift from Ernie King who strips the US east coast bare and for a relatively brief period the boats are able to attack unescorted merchies. Until the RCN steps up and stops that. And at that point the air and escort coverage is such that the only option is to attack fast defended convoys. But its winter and activity drops

Come spring 43 activity picks up. and the U boat arm is buttfucked in a matter of months, because it has to go into range of the escorts.
 
What I find interesting from the losses table is

1) The big losses due to aircraft in March - May 41. Assume this is due to Greece campaign and might include Greek and Yugoslav losses which sort of pad the total. Same with May June 1940, evacuation of France. Otherwise the losses are sort of unimpressive during the non evacuation times.

2) The losses to warships are low. Which we all knew, but it reinforces it was kind of dumb to risk Sharn+Geis+Bismarck against what was achieved, vs the fleet in being value of all the ships in the Baltic. Once the Italians are in, and the med is an active theater "fleet in being" matters.

3) E-boats, cool and all, but their anti shipping mission produces lame results, probably more useful if railed to the med or black sea


Good points, I always ignore the E-Boats for the same reason. In fact thinking of the M-Boots as 'channel destroyer's' made me conclude the tonnage-propulsion & armament's of the 200 or so 'E-Boats' , should instead have been combined with the tonnage -propulsion & armaments of the 200 or so M-Boots in order to make 200 more effective F-Boots.

Point 2 is why I never would invest in battleships , surface raiders are good enough and just needs to be some kind of AGS size raider with a Transom stern to boost sprint speed to 30 knots. But to have any sizable impact there needs to be many of them.
 
The production issue is not JUST building subs but training crews, each vessel needs a navigator, does not matter if its a sub or a BB, more navigators you need more training billets. U boat net gives good picture of the training regime. Its not pretty.

Pre war Germany cannot count on bases in Norway or the Atlantic coat of France so any LRMP pre war has to transit from Germany across an enemy country or by such a circuitous route it has no time on station. Its a non starter. And Pre war there is no active hostility from Italy and the MN to consider. Apart from pre war positioning any AMC has to transit past the RN to get to an operational area.


So 39/40 attempted close blockade fails because of the density of escorts and air cover.


.


Garbled POV .

In 1939 -40 there were 375 convoys sailed North Atlantic and 11 were attacked , but RN sources lament over the convoy escorts being to few and many convoys had trawlers as escorts. When U-Boats often attacked 4 ships per convoy in the first couple of years , after that there were enough WALLIE ASW platforms to limit convoy attacks to 1 per U-Boat. This is why that was called the 'first happy time'.


BTW LRMP was demanded from the start and the choice of a converted airliner into patrol in 1939/40- was brilliant compromise...since LW didn't want to give the KM anything. Best KM could do was to order Condors in a ton tor ton exchange with the other sea planes they historically ordered.
 
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BlondieBC

Banned
So at 250 miles per day (12 knots), its 8 days to cross. So the Numbers could be divided by 16 (8x2 (2 because they cant patrol at night) and then add some for tracking. I’m exaggerating because they want to locate the convoys in the western or eastern Half but maybe 200 aircraft (sustained).

That sounds about correct. Seems like 60 or so was enough to give Pearl Harbor reasonably good coverage. Or Midway during the battle. And we basically need two or three times this number. Probably one group out of Norway searching SW to North. One group out of NW France search NNW to West. And probably one group in reserve for training or other opportunities. An example might be one squadron is task with search patrols, second squadron tasked with keeping eyes over big convoys as wolf pack approaches. Or maybe second squadron has some attack ability. I figure of 60 planes in or near Brest France, about 20 head out most days of good weather.

So lets talk about the ramp up. The air frame production is not too bad. You start out with a planned strength of 60 patrol aircraft to patrol the North Sea and Baltic. Start planning about 1934, first delivery of air frames about 1936, full planned strength in late 1938. This should not seem to alarming to the UK, and requires a production peak rate of maybe 4 planes a month. This is the likely shorter range, model A. As this line winds down, you now are coming out with the better range second batch. Call it Model B. Probably planned for completion about 1941 as a part of Plan Z. The double orders once war starts. Production peak of 10 per month is all that will be needed. Minor note, these planes may carry some anti shipping weapons, but are more for search than kill.

I did the calculation/planning about a half decade or so ago, but that is the way I recall it.
 
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