Could nuclear weapons have gotten Germany to surrender in 45-47 without a Western Allies invasion of Germany?

[RCAF Brat]

Do we see the same shut down occurring as in @ with an active war against a better positioned Nazi Germany? I’m not so sure.

Some of figures I have seen refer to 3 plutonium bombs and 1 uranium bomb per month, and more:

Atomic Bomb: Decision -- Bomb Production Schedule, July 30, 1945

The Manhattan Project could make atomic bombs at an ever-increasing rate

www.dannen.com

- 3/month in August, 5/month in November, 7/month in December

All that doesn't even account for the possibility that the Americans will do as they did post war and use the U-235 that was meant for the second Little Boy type bomb to make cores for a modified Mk 3 device. Either by making pure uranium cores or by alloying it with plutonium. The uranium in one 12kt Little Boy bomb was enough fissile material for four Mk 3 fat Man bombs. So doing so would effectively double the production rate, and would likely only require one additional weapons test.

So instead of 3 Pu239 implosion bombs and 1 U235 gun bomb per month, you get 7 implosion bombs, either 3 Pu 239 and 4 U235 or 7 Pu/U alloy per month. So by holding off until a stockpile is built and having the surprise nuclear attack be in Feb 46 instead of OTL's Aug 45, you get 1 Little Boy (if the first unit isn't scrapped and the U235 recycled into Fat man cores), and 38 Fat Man (18 Pu239 and 20 U235) available for delivery to targets in both Germany and Japan. That is enough to utterly and irrecoverably devastate both countries at the same time.

 

[AlterKnacker]

IIRC Lend lease was only about 10-15% of Soviet trucks, planes, and tanks. Not insignificant, but also not enough to totally change the course of the war.

Checking wiki, looks like tanks (7000 from USA, 5000 from UK) were about 8% Soviet production.
The Soviets got over 90% of their rail equipment from lend-lease, however. 1,911 locomotives and 11,225 railcars from lend-lease, against 92 locomotives built in the USSR between 1942 and 1945.
The Soviets also got half a million trucks, and domestic production used American machine tools. Also, over four million tons of food, and over half of the US ammunition production went to the USSR.

Stalin, Khrushchev, and Zhukov all said that without US aid, they'd have lost the war.

So that fits the scenario supplied by OP -- a better u-boat war leading to a stagnant Russian Front and a delayed d-day. There are other possibllities, of course.
For a point of departure, maybe Carl Vinson isn't in office in the 1930s, and the USN shipbuilding doesn't get started until after the start of the war.

The fundamental problem for the Axis is that they just don't have the manpower or resources to take on both the Western Allies and the USSR. Against one or the other, they *might* have been able to force a stalemate, against both I think it's a truly unwinnable war. More U boats isn't gonna change that.

Right, a better u-boat war won't win against Western resources. It isn't complete ASB that it would help delay the inevitable, with a temporary stalemate in the East.

In regards the original question, I don't think the inital round of nukes will get an unconditional surrender. I think after 20 nukes a month for a few months, Germany would be in a state where some leaders would say that's enough. Whether that's piecemeal, or after a coup, hard to say.

 

[ObssesedNuker]

The Soviet Union was not invincible, and was running short on manpower 1944-45. They could have been at the very least stalemated, if the Western Front did not occur.

Not really? Soviet military manpower replacement in '44 was largely neck-in-neck with losses and even that was because the Soviets had started diverting manpower into economic reconstruction. The Class of 1927, which came of age in 1945, was not even mobilized as fully as it could have been for military tasks. The Soviets were only really "short on men" in a similar sense as the British, who were also by 1944 finding themselves having to make some balancing decisions on where to send it's manpower resources. Even without the Western Front, the manpower losses were sustainable for the Soviets. Whether that would have been the case without the OTHER elements of Western Allied war participation can be debated, however.

The Soviets got over 90% of their rail equipment from lend-lease, however. 1,911 locomotives and 11,225 railcars from lend-lease, against 92 locomotives built in the USSR between 1942 and 1945.

That's not 90% of Soviet rail equipment, that's merely 90% of what the Soviets manufactured during the war. Overwhelmingly, the USSR relied on it's pre-war stock of 25,000 locomotives and 680,000 rail cars. It lost around about 2,000 locomotives[1] during the war, so lend-lease really can only be said to account for about 7-8% of Soviet locomotives AT BEST[2].

[1]Can't remember how many railcars the Soviets lost.
[2]The proportion of lend-lease locomotives drops if we count the trains lost 4,000 German locomotives captured by the Soviets, but we really shouldn't count the latter since the overwhelming number of those were acquired in the first half of 1945.