Admiral Lütjens not a fanatical Nazi as portrayed in film
I lived in Germany for many years & I know the two least Nazified branches of the German Armed Forces during WWII were the Navy (Kriegsmarine) though this was more true of the surface fleet than the U-Boats & the Air Force (Luftwaffe).
Chief of Staff (Chef des Stabes): Kapitän zur See Harald Netzbandt was Jewish & served under Admiral Günther Lütjens & died with him & Captain Lindemann when the Bismarck was sunk by the Royal Navy on the morning of Tuesday 27th May 1941. There's photo's of Netzbandt meeting Hitler with other Kriegsmarine (German Navy) high rankers, the only visible difference being him giving a standard military salute rather than a heil.
Now that's an incredible high rank for an "untermensch" and if there's one that high (Fleet Command Staff) there must have been thousands in the lower ranks. He was a great Officer and apparently very highly appreciated by Admiral Günther Lütjens.
In a published historical inquiry in 1965 by Jürgen Rohwer over the sinking of the Jewish refugee-ships Struma and Mefkure in the Black Sea, it is proven that both Jew-ships had not been sunk by the Kriegsmarine as has been claimed until now.
"After as before, Jews were able to leave the country from the Black Sea ports. Even more: the Supreme Commander of the Kriegsmarine, Grand Admiral Dönitz, even gave orders not to hinder the Jew-transports Bella Citta, Maritza, and Milka departing from Costanza (Romania) in March and April 1944, but to treat them as normal ships.
The German Naval leadership instructed U-boats to tow those three ships past the mine barrages. It was Soviet warships, on the other hand, that sunk the Struma and the Mefkure.