Overlord and Dragoon land on the same day

[Aber]

Since 15th Army Group had more or less broken through the Gothic line before exhaustion and the rain stopped them, an earlier stronger assault ...

...would more than likely carry the allies across the Apennines before the rains kick in, but then what?
You now have an exhausted force standing before the Alps with the Italian winter fast approaching. The prudent thing to do is wind down operations and regroup for a Spring offensive.

or use a Corps or 2 to clear Southern France of whatever German forces are left there.

In Italy you clear the area between Milan and Switzerland, and have 1 Corps (including 10th Mountain Division) aiming for Lake Garda/ Bolzano/Brenner Pass although progress will be slow. The rest drive east towards Trieste in the lowlands using the threat of amphibious operations to unhinge any defensive lines based on rivers. You don't need to push far into the mountains because of the supply problems the Germans will have fighting there.

[Carl Schwamberger]

A couple years ago i worked out a scenario on this for the game board. Actually several scenarios. The first proposed a operation Anvil approx six weeks ahead of Op Neptune. The second placed the Anvil Op closer to Neptune in time; 0-14 days. The third was a proposal from another interested party & proposed that Op Shingle be canceled in favor of a January Anvil Op. This last was the most heavily tested of the three. The 'simultaneous' scenario was the least being more of a timing & OB study.

Because of the interest generated in this subject I used three games to cross check the concepts. Two were stratigc level campaign games of similar scope and scale. The other was a tactical game I used to look at some of the differences in the Neptune operation on the Normandy coast. I worked through several rounds to test some extra rules and work out OB & other questions, multiple rounds with the stratigc games were played, about a even number each.

I made a couple assumptions in all these. 1. Allied deceptions ops would be as sucessfull as in OTL. 2. The amphibious fleet would not differ from OTL. 3. OB would vary slightly for both sides. In the case of #2 this mean that no matter how one cut it a Neptune or Overlord operation on the scale of OTL could not be mounted with a winter or spring Anvil operation. Depending on the time length between the two invasions Op Neptune varied between something the size of COSSACS 1943 plan, and Montys January four beach plan. The five beach plan post March 1944 could not be achieved. The OB variants consisted of adding the US 2d Cav Div back to Allied combat strength, accelerating the deployment of a infantry division from the US by a few weeks, and a air group or two from the US. For the Germans rebuilding of a few divisions was accelerated & IIRC a unit sent to the east in the spring of 1944 was retained in the west. These formations did not make a decisive difference. Their inclusion represented logical decisions by each side given the earlier campaign in France.

For both the January and the April variant two corps were used for the initial invasion of the Riviera. The follow up brought the Allied force in the Riveria after eight weeks up to something similar in strength to the OTL 6th Army Group in october 1944. This still allowed the tranfer of some amphibious fleet to the UK for a May 1944 Op Neptune. At that date it was possible to mount a four corps/beach assault, similar to Montgomerys January 44 plan. Or perhaps slightly weaker. If the Neptune Op were delayed to June as OTL then it could be somewhat stronger, tho a initial assault of five corps/beaches as OTL look beyond reach. If the Anvil Op is executed in April or May then it is difficult to transfer any significant amphib squadrons to the UK & Op Neptune is limited to a three corps/beach assault. Build up is proportionalty slower until the prefab Mulberry harbors are in place, then it accelerates.

What either the January or the April Anvil Op does is place the German side in a bad choice. If the considerable reserves in France and Italy are redeployed to confine the Allied 6th AG in the Riviera then north west France becomes vulnerable. Not defenseless, but the sort of defense in Normandy of OTL cant be mounted. At the end of 90 days the Allies still have two powerful army groups ashore in NW France & the wirht of the German reserve is in the south pining the Allied 6th AG to the coast. Conversely if the weight of the German reserves are kept in Italy & NW France then the 6th AG has the ability to expand and position itself for a offensive north when the Neptune Op is executed. The Allied side also has the option of redirecting a portion of the US units headed for the UK to the 6th AG instead. Getting a extra couple corps in action in S France in March or April benefited the Allied side in these games more than having them sit in the UK for a couple months.

A earlier invasion revealed a second significant problem for the German side. That is the forces in France were far worse prepared in the winter/spring. What I found when picking over unit histories is the units withdrawn from the East to rebuild were not close to combat ready in January-March. Neither were those newly formed in late 43 or early 44. Equipment was reduced training allowances and training had not progressed far. The 17th SS Pz Grenadier is a example. In Febuary training had progressed only as far as company/battalion level training. Motorization amounted to less than half of the TO/TE & was mostly French relics passed over by previous requsitions. The transportation shortage was so acute the division commander formed a horse drawn wagon service to move supplies from the railheads to the divisions field & garrison locations. It was not until April the 17th SS was able to train as a motorized formation. If my information is correct its assualt gun battalion was not equipped until late May.

While the Allied armies are smaller in numbers in January-May than in June the difference did not show acutely as with the Germans. More important is the Allied corps present are fully equiped (excepting the French) and the components had completed full training cycles.

[Kingfish]

or use a Corps or 2 to clear Southern France of whatever German forces are left there.

With what troops is the question.
Using the original Dragoon force to beef up an earlier Apennines offensive would pretty much nix them off the list of available troops for a Southern France amphibious Op, and the rest of 15th AG would not be in any better shape.

[Gooner1]

...would more than likely carry the allies across the Apennines before the rains kick in, but then what?
You now have an exhausted force standing before the Alps with the Italian winter fast approaching. The prudent thing to do is wind down operations and regroup for a Spring offensive.

Well 15th Army Group would have achieved a great victory. Northern Italy was responsible for about 15% of German armaments output as well being a major food supplier. The Allied armies would be poised to advance on Vienna, Hungary or Yugoslavia and the Mediterranean air forces would be 200km closer to the Reich.

[Gooner1]

or use a Corps or 2 to clear Southern France of whatever German forces are left there.

With what troops is the question.

Pick any from the 95th, 26th, 104th, 44th and 104th infantry divisons and 9th, 10th and 12th armoured divisions is my suggestion,

http://www.ibiblio.org/hyperwar/USA/USA ... ic2-D.html

[Kingfish]

Well 15th Army Group would have achieved a great victory. Northern Italy was responsible for about 15% of German armaments output as well being a major food supplier. The Allied armies would be poised to advance on Vienna, Hungary or Yugoslavia and the Mediterranean air forces would be 200km closer to the Reich.

There is no disputing the allies being able to achieve this, or it's value to the war effort. What is in dispute it whether the followup can be achieved before the weather shuts everything down for the winter.

[Aber]

Well 15th Army Group would have achieved a great victory. Northern Italy was responsible for about 15% of German armaments output as well being a major food supplier. The Allied armies would be poised to advance on Vienna, Hungary or Yugoslavia and the Mediterranean air forces would be 200km closer to the Reich.

There is no disputing the allies being able to achieve this, or it's value to the war effort. What is in dispute it whether the followup can be achieved before the weather shuts everything down for the winter.

After the Appenines have been crossed, then the Allies greater mobility will be an advantage in the pursuit. Also I'm not convinced that winter will shut down operations in the Po valley, or the lowlands towards Venice and Trieste as amphibious assault capacity makes defence lines based on rivers far less effective.

[Kingfish]

After the Appenines have been crossed, then the Allies greater mobility will be an advantage in the pursuit. Also I'm not convinced that winter will shut down operations in the Po valley, or the lowlands towards Venice and Trieste as amphibious assault capacity makes defence lines based on rivers far less effective.

It's not so much the weather, although it certainly will have an impact, but rather the accumulative effect of almost continuous ops since the beginning of the year. Exhaustion was very much an issue for the allies as the year wound down.

BTW, where is all this amphibious assault capacity coming from?
Normandy + Dragoon + Adriatic?

[Aber]

Amphibious capability is not needed at the same time. Normandy in the summer, Mediterranean in the autumn and winter.

Exhaustion only becomes an issue, if you don't rotate divisions out of the frontline - it would need a bit more work with the order of battle to show that it could be mostly avoided.

[Kingfish]

Exhaustion only becomes an issue, if you don't rotate divisions out of the frontline - it would need a bit more work with the order of battle to show that it could be mostly avoided.

Isn't this what is the issue here?
Diadem / Buffalo followed by an accelerated Olive, followed in turn by a push towards the Brenner pass / Trieste?
That's 3 major ops and an advance of 700+kms in less than 6 months.

Bear in mind manpower issues were also having an effect - the Poles were withdrawn into army reserve because of shortages, and the British were really feeling the pinch, with an entire division being disbanded as a result. And there is also the Canadian transfer to NWE just around the corner.

Granted, fresh divisions were en route, but whats the gain if the ones already in theater are ground down to skeletons?

[Carl Schwamberger]

Well 15th Army Group would have achieved a great victory. Northern Italy was responsible for about 15% of German armaments output as well being a major food supplier. ...

If its only 15% why bother with it? The Ruhr, Saar, & upper Rhine represented 50% or greater of Germanys remaining industrial capacity.

Committing the weight of Allied forces to the heart of the beast makes more sense. Getting at half Germanys industrial production is liable to collapse the entire system. Detaching 15% in Italy; I'l let folks draw their own conclusions. Also from the perspective of January 1944 there are less intimidating mountain ranges to fight across in France, a better transportation structure, and a population much more likely to join you in fighting the Germans. By January it was redundantly clear the Italians were not effectively fighting anyone.

As for Vienna & the rest, they lay behind yet more mountain ranges if approached from the south. Conversely Hamburg, Essen, Strausberg, Munich... are approached across the north west European plain with some forrests & a few uplands as the primary obstacle.

[Carl Schwamberger]

Amphibious capability is not needed at the same time. Normandy in the summer, Mediterranean in the autumn and winter.

....

Precisely. Even without the concentration of the amphib fleet as in OTL the advantage of having a third of the Allied invasion, the 6th AG, fighting in France months earlier looks like a huge advantage.

[Aber]

Well 15th Army Group would have achieved a great victory. Northern Italy was responsible for about 15% of German armaments output as well being a major food supplier. ...

If its only 15% why bother with it? The Ruhr, Saar, & upper Rhine represented 50% or greater of Germanys remaining industrial capacity.

And what did the 6th Army Group contribute to the Ruhr, THE major target?

As for Vienna & the rest, they lay behind yet more mountain ranges if approached from the south

Agreed, but nobody has really been arguing about them, just that extending the campaign in Italy over the summer of 1944 to the foothills of the Alps and towards Trieste, before reducing numbers in Italy, would have been more useful than Dragoon in August 1944.

Given that commanders at the time were split (and not just on nationality grounds), it's not surprising that the argument continues.

[Kingfish]

And what did the 6th Army Group contribute to the Ruhr, THE major target?

A couple off the top of my head:
-Securing the allied right flank while tying down elements of two German armies
-Threatening a Rhine crossing long before 12th or 21st AG were in position to do so.
-capture of Marseilles and Toulon, along with the relatively intact rail/road net in Southern France

To really appreciate its contribution one only needs to envision a scenario without 6th AG on the line. Imagine the Ardennes offensive with the US VIII Corp stretched even further and no possibility of Patton's III Corp redeploying to relieve Bastogne.

Agreed, but nobody has really been arguing about them, just that extending the campaign in Italy over the summer of 1944 to the foothills of the Alps and towards Trieste, before reducing numbers in Italy, would have been more useful than Dragoon in August 1944.

But pushing towards the Alps does not benefit the campaign in NWE in any way, whereas the points I mentioned above directly contribute to the campaign. The capture of the French ports alone would be of far greater value than the capture of the Po river valley.

[Gooner1]

What is in dispute it whether the followup can be achieved before the weather shuts everything down for the winter.

Why does that matter though? The Allied armies in NWE/ETO were stuck on the fringes of the Reich until Spring '45 themselves.