[hn_throw2025]

“during WWII, the US Navy… winning the U-boat war in the Atlantic”

Sounds like typical US revisionist history.

They developed ASDIC? HF/DF? Hedgehog? Even the depth charge?

No, that was all the British.

I would say technological development plus the Enigma decrypts were the biggest factor.

[pjmorris]

Yes.

"When whole squadrons of very long-range aircraft were operating out of bases in the Shetlands, Northern Ireland, Iceland, Greenland, and Newfoundland (and, after mid-1943, the Azores), and when the Bay of Biscay could be patrolled all through the night by aircraft equipped with centimetric radar, Leigh Lights, depth charges, acoustic torpedoes, even rockets, Doenitz’s submarines knew no rest." [0]

[0] Kennedy, Paul. Engineers of Victory: The Problem Solvers Who Turned The Tide in the Second World War, from the chapter 'How to Get Convoys Safely Across the Atlantic'

[grvdrm]

Fascinating book. I think I finished it!

[cladopa]

>No, that was all the British.

And not even British. For example most of the Enigma decryption was the genius work of a Polish man. Britain received the immigration of half the Nobel prices of the world in a couple years as the jews escaped nazism.

[argsnd]

The technologies listed aside from the Enigma were largely actually British (I say largely because Canadians were deeply involved in some cases)

[hn_throw2025]

The original Bomba was the genius work of a Polish man, but was no use from 1938-1939 when the Enigma cipher was strengthened. At which point the Turing-Welchman Bombe was developed. The Battle of the Atlantic ran between 1939 and 1945.

For the much harder Lorenz cipher used by German High Command from 1940, the Colossus machine was developed by Tommy Flowers at the GPO and became operational in 1944.

None of which involved the US Navy, which was my original point.

[superxpro12]

Also consider the simple fact that, you know, the US was sending entire convoys UNGUARDED for years.

And only when significant losses mounted did they decide to send some escorts.