Logistical Question-Change the date of D-Day

[TFSmith121]

Yep, that's my point

Among other things the beach defenses of 1944 were not yet built in April - August 1943. Before the construction program the costal defense was mostly a outpost line of some MG nests with sandbags and a phone to call in a warning. Before Rommel took over the strategy was to hold the ports and fight the invasion inland. There were not enough German infantry in France in the summer of 1943 to defend all the potiential landing sites as in the spring of 1944.

And it is worth considering that even on the most heavily defended beach in 1944, the 1st and 29th infantry divisions were through the beach defenses and moving inland before the day was half over...

In 1943, OMAHA would have been like UTAH was, historically...

Best,

 

[Saphroneth]

And it is worth considering that even on the most heavily defended beach in 1944, the 1st and 29th infantry divisions were through the beach defenses and moving inland before the day was half over...

In 1943, OMAHA would have been like UTAH was, historically...

Best,

It speaks volumes for how well prepared an operation is when the unexpected presence of an entire enemy infantry division which had been conducting anti-invasion exercises... barely slowed the Allies down.

 

[UrbanRedneck]

One cannot know all the factors that date alone cannot count for. for example:

1. The German commander canceled the German patrol boats going out that night so their was little pre warning.
2. Hitler waited quite a while before sending in reinforcements. We dont know if that would have happened.
3. Would "the man who never was" operation to make the Germans think the allies were going to hit elsewhere be done and be so successful?
4. Might a bad storm suddenly come up on the new date?

You guys can probably come up with many more.

 

[Carl Schwamberger]

And it is worth considering that even on the most heavily defended beach in 1944, the 1st and 29th infantry divisions were through the beach defenses and moving inland before the day was half over...

In 1943, OMAHA would have been like UTAH was, historically...

Best,

Or May 1944. the 352d Division had moved to the Calvados coast from the west side of the Cotentin just the previous week. Until then it was only a regiment of the 716th Divisions Georgians & assorted 'Ossies' defending Omaha Beach. Everyone here familar with the Koreans captured there?

One cannot know all the factors that date alone cannot count for. for example:

1. The German commander canceled the German patrol boats going out that night so their was little pre warning.

I found a description of a crewman of boat sent out to repair a air navigation bouy that night. They were unable to return to Le Havre & the commander ran it aground near Caen to escape the Allied destroyers & minesweepers closing in on the coast.

2. Hitler waited quite a while before sending in reinforcements. We dont know if that would have happened.

We can speculate based on the fate of the several divisions and corps HQ that were ordered to rush straight to the invasion site.

3. Would "the man who never was" operation to make the Germans think the allies were going to hit elsewhere be done and be so successful?

Re: Operation Fortitude & the Double Cross system.

4. Might a bad storm suddenly come up on the new date?

The next date for low tide at dawn was just as the freak storm of late June blew in. 14 day tide cycle + 6th June = 20 June Conversely the low tide dates of May were adequate weather. Not perfect, but adequate.

 

[Saphroneth]

If reinforcements had rushed to the landing OTL, the result might have gone a little better for the Germans (OTL they were forced to plug in units as they arrived, and had no chance to really build a reserve). But on the other hand the "transport plan" had made it pretty damned hard to move troops quickly (a Tallboy collapsing a railway tunnel, for example) and it's not as though the Germans would have been immune to the "Bocage effect" slowing advances. They wouldn't have been able to actually throw the Allies into the sea once a lodgement was obtained. (One advantage of choosing Normandy - that super defensive terrain does cut both ways.)

 

[ivanotter]

Should we try to get it back on track:

Consequences of a seriously delayed D-Day.

Ivan

 

[Saphroneth]

Should we try to get it back on track:

Consequences of a seriously delayed D-Day.

Ivan

Okay...
If D-day is delayed two weeks, then the Channel Storm hits the invasion (unless it was predicted by the meteorologists, in which case it's delayed another two weeks). If the invasion gets stormed, that's a serious problem.

If it's delayed by a month, then there might be some major transfer of troops east going on. This is the point at which Operation Bagration rips the heart out of Army Group Centre. The Allies might actually not get stuck in the bocage for as long if there's been such a drawdown of troops east, though the side effect might well be that there's a fighting retreat across France instead of the dash across France of OTL.
Politically, if Bagration is what caused such a drawdown, then Stalin will be very pleased with himself indeed. He made the "second front" possible...

 

[ivanotter]

D-Day April 1945?

 

[Saphroneth]

D-Day April 1945?

I actually think that the Nazis would have been rushing to reinforce the Reich well before then. Even a landing in Winter is possible against no opposition...

 

[Carl Schwamberger]

Ok, delay...

Eisenhower badly wanted Op Anvil executed in April. When in January it became clear the new up scaled Overlord plan could not be executed in May or early June with a April Anvil Op Ike spent a week harrasing staff across the UK and Mediterranean in a effort to find enough amphib lift to pull off a barely adaquate Anvil reduced Op.

So, lets supose Ike had decided a early & robust Anvil operation was more important than a May Overlord operation. The latter ends up delayed until 2-4 July (next dawn/low tide combination after the June storm), the former has a Allied army group well established in south France and the port of Marsailles open for business by mid May. Having that & a collapse of their defense in central Italy would give the Germans something to think over. With a cluster of ports it is possible to divert & accelerate the shipment of combat formations from the US to Marsallies. Hypothetically up to three Allied armies of 24+ divisions could be on the ground in south France by 1 July without compromising the Overlord & Neptune Ops.

 

[ivanotter]

Carl, Intreesting thought.

In essence, Overlord is delayed by a few weeks and Anvil becomes the major show.

When is the latest date this swop can happen? I fear it is much earlier than a May time frame.

Overlord took a considerable amount of staff work and many months to get sorted. The distance for transports is greater and that means a slower turn-around time.

Just something as simple as gunship fire support time tables and schedules are not simple to do. Replenishment, ammo, fuel, and so on.

Air support is another factor.

It might be easy to get ashore, but then what? That was exactly what Brooke also asked Marshall in '43. With no good answer forthcoming.

If Anvil is severely downscaled compared to what Overlord would have been, the chances of success might not be so great.

I like using Brooke as a source as his notes were from the same day as discussions were held, not edited years later. Brooke does not mention anything about a chance of a serious delay of Overlord until '45. Unfortunately. So we will never really know.

Starting a campaign in October/November in Northern Europe is not a good idea. The days are short, the weather (air support) is bad. It would be Hurtgen from the very start of the campaign. Not a good prospective.

So, it comes down to some hasrd choises again:

1) If the weather/harbour damage/.. makes Overlord impossible during June, July August and September, it has to be '45. My bet on the earliest is then April '45.

2) Anvil cannot become the major theatre as the planning and re-direction of forces cannot be achieved before September/October. That makes either Anvil redundant or has to campaign during winter (not a great perspective in Northern Europe).

3) If Overlord is this much delayed, will Soviet:
be fought to a standstill somewhere in Poland?
Occupy the entire Germany before Overlord in April '45.

Ivan

 

[TFSmith121]

Yep - there's a lot of drama to OVERLORD, but if

It speaks volumes for how well prepared an operation is when the unexpected presence of an entire enemy infantry division which had been conducting anti-invasion exercises... barely slowed the Allies down.

Yep - there's a lot of drama to OVERLORD, but if you really look at the correlation of forces, it was very much in the Allies' favor. Complete air and naval supremacy has that impact, and the facts are the six Allied infantry divisions that went ashore basically blew past the German beach defenses...

The toughest part of the campaign was the 6-8 weeks after the invasion to establish a lodgment large enough to give two field armies enough room to maneuver - and to grind away the German forces in the theater.

Best,

 

[TFSmith121]

Yep; put the 716th Division equivalent in 1943 against

Or May 1944. the 352d Division had moved to the Calvados coast from the west side of the Cotentin just the previous week. Until then it was only a regiment of the 716th Divisions Georgians & assorted 'Ossies' defending Omaha Beach. Everyone here familar with the Koreans captured there?

Yep; put the 716th Division equivalent of 1943 against the 1st Division of 1943 and it is no contest.

Cripes, put the 716th Division equivalent of 1943 against the 1st Division of 1942 and its no contest.

Best,

 

[TFSmith121]

This I doubt, epsecially given that GCM had

It might be easy to get ashore, but then what? That was exactly what Brooke also asked Marshall in '43. With no good answer forthcoming.

been considering how to win a land war against Germany in northwestern Europe since 1917...

But:

1) Secure lodgment in Normandy-Brittany;
2) Breakout and drive for Paris (center of French road and rail network);
3) Secure lodgement in Provence and open up southern French ports;
4) Drive northeast into Belgium aimed at opening Antwerp;
5) Drive east toward Metz to secure France and connect with forces moving north from Provence;
6) Go on defensive in winter of 1943-44;
7) Cross the Franco-German border, and push through Westwall defenses in spring of 1944;
8) Cross Rhine in summer of 1944 and encircle Ruhr;
9) Once Ruhr is no longer producing for Germna war economy, push northeast toward Berlin and southeast toward Vienna;
10) Force German surrender by autumn, 1944;
11) Meet Russians in Warsaw and Bratislava.

Best,

 

[Saphroneth]

Yep - there's a lot of drama to OVERLORD, but if you really look at the correlation of forces, it was very much in the Allies' favor. Complete air and naval supremacy has that impact, and the facts are the six Allied infantry divisions that went ashore basically blew past the German beach defenses...

The toughest part of the campaign was the 6-8 weeks after the invasion to establish a lodgment large enough to give two field armies enough room to maneuver - and to grind away the German forces in the theater.

Best,

Indeed. Given how much of a pig the terrain was, 6-8 weeks isn't terrible.

 

[Aber]

Attached is a badly copied map of one of the COSSAC plans.

Where did you find this?

 

[Aber]

been considering how to win a land war against Germany in northwestern Europe since 1917...

But:

3) Secure lodgement in Provence and open up southern French ports;

If you are landing in Northern France in 1943, then the Mediterranean campaign will have been delayed and so there will be no access to ports in southern France, as you need to clear Sardinia and Corsica first.

4) Drive northeast into Belgium aimed at opening Antwerp;

Remember only about half the US Army divisions were ready for combat in 1943

5) Drive east toward Metz to secure France and connect with forces moving north from Provence;

Not needed if there are no landings in southern France

6) Go on defensive in winter of 1943-44;

Why?

 

[TFSmith121]

Not at all; putting an army group ashore against

Indeed. Given how much of a pig the terrain was, 6-8 weeks isn't terrible.

prepared defenses and breaking loose into mobile warfare in two months is phenomenal, actually; consider what it took for an army group to do the same in 1914 or 1918...

Best,

 

[TFSmith121]

Except remember that in the 12 months

If you are landing in Northern France in 1943, then the Mediterranean campaign will have been delayed and so there will be no access to ports in southern France, as you need to clear Sardinia and Corsica first.

Remember only about half the US Army divisions were ready for combat in 1943

Not needed if there are no landings in southern France

Why?

Remember, in the 12 months from November, 1942 to November, 1943, the Allies mounted:

TORCH (5 assault division equivalents afloat simultaneously) at as many widely-separated beachheads (Safi, Casablanca, Port Lyatuey, Oran, Algiers) (November, 1942);
CORKSCREW (1 division afloat) (June, 1943);
HUSKY (eight divisions+) (July, 1943);
BAYTOWN (two divisions+) (September, 1943);
AVALANCHE (four divisions+) (September, 1943);

In addition, two administrative landings were made in division strength (SLAPSTICK and VESUVE, both in September, 1943) and brigade+ (ACCOLADE, September, 1943); there were smaller (battalion+) landings made during the Mediterranean, Sicilian, and Italian campaigns.

All of the above is entirely separate from any operations made possible by scaling back the Allied operations in the Pacific and Indian Ocean theaters in 1943, as well, much less the supply operations (Persian Corridor, Arctic, North Pacific, and CBI) designed to help sustain the Soviets and Chinese in 1943.

Given the above, the Allies had the resouces to mount significant operations in both NW Europe and the Western Med in 1943.

As far as the number of US divisions available for operations in NW Europe in 1943, the baseline version of ROUNDUP foresaw 30 US divisions available for the assault and immediate follow-up, with more to come as the campaign went on; interestingly enough, up until July, 1942 (2nd Washington) only eight US divisions (including two USMC) were deployed to or earmarked for the Pacific, leaving 30 divisions that had all mobilized in 1940-41, in the ETO or CONUS. In addition, the US divisions mobilized in 1942 would become available for the ETO at ~M+18 months.

Obviously, the number of combat ready British & Commonwealth divisions in the ETO was higher in 1943 than it was in 1944.

Again, the Allies had the resources for two fronts (NW Europe and Provence) in 1943.

Defensive in the winter of 1943-44 would have allowed France to be better organized as a communications zone.

Best,

 

[Saphroneth]

prepared defenses and breaking loose into mobile warfare in two months is phenomenal, actually; consider what it took for an army group to do the same in 1914 or 1918...

Best,

True, though I think to compare like-with-like we have to use other amphibious operations. Anzio took four months, Gallipoli just plain didn't undergo the transition, and it's hard to come up with other examples from pre-Overlord.

Also, just as a friendly note, if you title your posts and they're part of a sentence then please re-state the sentence in the body. It's easier to follow if you don't have a sentence split between title and body