From: Beloit, USA
I don't think that there is a realistic way for Hitler to win WWII.
Operation Sealion/BoB e.t.c.:
Only a part of the BEF was encircled at Dunkirk, the rest continued to fight until the fall of France.
So, even if there would have been no evacuation from Dunkirk, the UK would still have more than enough first-line-professional troops to defend the UK.
"Supplying war" by Martin van Creveld indicates that logistic problems would have stopped Rommel anyway.
Waiting longer to start WWII:
The economic potential of the UK and France together was bigger thatn Germanies potential. After Munich 1938 (and, especially, after the invasion of the remainins Czechoslovalia in March, 1939), the allies started to gear up. Having two more years of an armarment race would have resulted in a Germany in 1941 that would have been stronger than in 1939, but it would have been weaker (in 1941) in relation to the UK/France than in 1939.
Waiting longer with Barbarossa:
The red army was in the process of being reorganized. After the Finnland desaster, even Stalin had to realize that the grerat purge wasn't a smart idea regarding the effectiveness of the red army. Wait one more year, and Germany would not have advanced even close to Moscow.
Building submarines in place for battleships:
Bismark: 196.8 Million Reichsmark
Tirpitz: 181.6 Million Reichsmark
Scharnhorst: 143.5 Million Reichsmark
Gneisenau: 146.2 Million Reichsmark
(Source: Breyer, Siegfried: "Schlachtschiffe und Schlachtkreuzer 1905-1970", Karl Mueller Verlag 1993 (first printed in 1969)
IIRC, a type VII-sub was available for 4 Million Reichsmark. Please note that Bismark and Tirpitz where finished *after* WWII started.
Let's say Germany could have more than 100 additional submarines in September 1939. In our time line they had 61(?), including the training boates in the baltic.
This looks impressive. The UK would have serious trouble in September 1939 and very serious trouble after the fall of France (when Germany had subbases on the atlantic coast).
There is just one minor problem.
In the late 30s, the UK build the King George V-class to counter the new german vessels.
If Germany would have build no battleships but submarines, would the UK still have behaved like in our time line? Or, would they have switched production from battleships to escorts (frigates and corvettes)?
This would mean that there would be a convoy system *much* earlier, that these convoys would be sufficiently protected (more than 8 escorts for one convoy and the situation for the attacking submarine becomes very difficult).
Furthermore, the public opinion in the UK would have remembered the german submarine campaign of WWI and probably allowed to spend more money on defense.
So, this doesn't seem to be a war-winner.
Capturing Moscow in 1941:
This would have been difficult (again, van creveld's "Supplying war"), and why should the USSR have stopped fighting after the fall of Moscow? Isn't there a danger that they would have killed Stalin, thereby removing Hitlers best leader (I regard Stalin as Hitlers best military leader as well as I regard Hitler as the best military leader working for the allies)?
Wonder weapons (Tiger, Royal Tiger, Me262, Arado0234, TypeXXI):
Tiger, Royal Tiger:
There is a wonderfull book by Christopher Wilbeck: "Sledgehammers". It is an analysis of the german heavy tank units. Nice prototypes, but highly unreliable. Other books - the combat histories for heavy tank units 503, 507 and 508 - support this. Between the lines you read of horrible losses due to breakdowns e.t.c., especially in the history for unit 507. By the time they would have ironed out these toothing problems, the allies would have the Pershing, the Centurion, the IS-3 e.t.c. in huge numbers. And more than enough fighter-bombers.
Interesting constructions. The Me-262 had an armament that was dangerous for any allied heavy bomber. However, without materials like tungsten, they could not be built. Germany built them despite shortages of these materials, resulting in extremely unreliable engines.
Moreover, you could not dogfight with a Me-262. When turning hard, it lost speed at an alarming rate. Once having lost the speed advantage, a P-51 or P-47 had a very good chnce to down a Me-262. When starting and landing, a Me-262 would need fighter planes for protection!
Great construction. And the potential for mass construction. Building them in segments can't be wrong. The US did it with their liberty ships, so why shouldn't Germany be able to use that technology, too?
There is only a minor problem.
A liberty ship does normally not operate underwater. It's draft was 27 ft 9.25 in (8.5 m). While the draft of a type XXI was smaller (6.3 Meters), the pressure in the welding seams would have been at maximum when diving. At 100 ft deep, it would have been more than 3 times pressure than for a liberty ship. It is highly unlikely that those massed-produced type XXIs would have been very reliable. Moreover, at this point of the war, the allies had more than enough escort ships to counter the submarine thread.
Oh, and please do not forget, there was one wonder weapon that had the potential to decide the war on it's own: The atomic bomb. Only problem was that it was an US wonder weapon and that the US would have it sooner and in huger quantities than germany.
So, I really see no chance for a german victory and only a low chance for preventing complete defeat. Maybe....
....giving independence to Belorussia, Ukranine e.t.c., thereby winning the local population as allies (would have demanded a complete change in course for the NSDAP, but might have led to a bloody stalemate on the eastern front)
....after the fall of France, declaring that lorraine and versage (the territories captured by Germany in 1870/71, recaptured by France in 1914/18) would be the last and final territorial demand. Give independence to Poland (only annex territories that where part of the german empire between 1871 and 1914), do the same with France, but keep France occupied as long as UK is at war. No BoB (except a few reconnisance flights over england, and a massive CAP in northern France), no submarine campaign (except against warships)=less support in the USA for the UK. Problem: What if the UK is still at war in, lets say, 1943 and at this moment, the USSR attacks? And, it would demand a huge change for the NSDAP).
What if the Georg Elser would have been successfull? Hitler would have been killed on November 8th, 1939; Goering would have taken over. Since Goering was more interested in his personal well-being, there might have been the possibility for a radical change in the german politics - don't get me wrong, Goering was an antisemitic criminal, but IMHO not as worse as Hitler. He followed Hitler in everything (including the Holocaust), but would he have done such things without Hitler?
Just my 0.02 Euro,