Great movie!
,,,
And also the great 4-part BBC documentary "The Real Heroes of Telemark", with interviews with the actual commandos!
That documentary was made as a backlash against (what the documentary makers thought was) a terrible, inaccurate film that belittled the people it was based on. I personally don't think the film was that bad, after all everything adapted into a film has to make compromises, but do find it interesting why these things are made.
The is another documentary on a related topic - not about the heros of Telemark, but on
what was really in the sunken train. Documentary was made by PBS (USA's Public Broadcast) called "
Hilter's Sunken Secret".
First thing you will notice is the the Hollywood reproduction did a good job in picturing the production facility and the equipment.
Second is, they also have some interviews with the actual people involved such as Knut Lier Hansen.
Third, they documented tests of samples from the sunken ferry (barrel number 26) to confirmed the content of the shipment manifest in the document archive at the plant. The tests confirmed the train content were indeed
containers of heavy water each in concentration stated in the manifest. 15 tons of partially purified heavy water was to be shipped during closure of the hydro plant.
Fourth, according to the manifest, the barrels with higher concentration of heavy water were (mostly) partially filled. They floated. Thus, some barrels survived the sinking and were shipped to Berlin.
That aside. Heavy water is useful for making the a-bomb, but it is not the only thing necessary.
Although Germany may not necessary had the practical solutions to issues such as how to
artificially start the chain reaction but they surely could figure out. It is clear that Germany understood the principal of making such a bomb. It is also clear (from documents of the day) that
Germany didn't put it on the front burner. The NAZI leadership felt that the war will be done in less than a few years, so a bomb taking more than a few years to make is not useful.
So while it continued, it was not an important project. The allies found what was the
experiment reactor in the cave near/under a Church in Haigerloch Bavaria
that hasn't begun to work.
Given how much resources it took the USA to make the bomb,
my opinion is that Germany simply did not have the resource to get it done then even had they tried their best. USA, in cooperation with England, Canada and other allies, spend billions (of 1940 dollars) to make it, over 50,000 people and using multiple plants running non-stop (for years) to refine uranium and plutonium. Germany certainly had the scientist then, but by 1942, if they had any working reactors, none of them could feasibly function at necessary pace as they were bomb by the USA during the day, and bomb by Britain during the night. They would not have been able to enriched enough uranium or plutonium to make the bomb before the war ends - even if all other bomb-related things went well for them.
So, in
my opinion, the heavy water getting to Berlin or not would not have been a show stopper. There were other things that they couldn't get done that stopped the show. But, we didn't know that then. We didn't even know how much it would take to make the bomb ourselves. So, it would have been an unwise gamble not to stop the heavy water shipment getting to Berlin.