Hello!
Well, you have to know that HF DF (High Frequency Direction Finding) is little bit more complicated than ordinary, MF (Middle Frequency) DF.
First of all, the antennas for HF DF are more complext, in order to abolish the ionosphere efect.
Simply, all nations had chains of HF DF, and few DF's, at least three, could to fix a submarine position, when she used her HF radio transmitter, by radio bearings.
Of course, the all bearings had to be collected on one place, operattine centre, where naval officers ploted submarines, etc.
The most important is that all actions, including HF DF, had to be co-ordinated, and all information- submarines' positions, obtained by HF DF, broken ciphered messages, agents' reports etc etc had to be used together, and after that the responsible person had to order which kind of action and where and when had to be taken!
Best regards!
Funkmeister