Hello all!

I wrote that the wolfpack were not the perfect answer on the allies' convoy system, but the best possible.
The German navy hadn't its own airplanes, although some German naval officers served in the Air Force before the war. Later they were sent back to the Navy, and I realized that they used radio navigation often and better than their colleagues without air force experiences.
The German Air Force pilots weren't able to fix their airplanes' positions when were over the sea.
Ok, because of that, and perhaps because some another reasons, the system was as follows:
1. When the German airplanes saw a convoy they sent report about it to the Headquarter, including number of ships in the convoy, their course and speed, by radio, on High Frequency (HF).
2. The Headquarter ordered to the airplanes to send beacon signals, on Medium Frequency (MF) to the U-boats in the area.
3. The headquarter informed U-boats about the convoy and that the airplanes will send bearing signals.
4. The U-boats received beacon signals from the airplanes, took the bearing, and sent message (on HF) to the Headquarter (their own position, azimuth obtained by bearing), and the Headquarter obtained the convoy's position by crossing the azimuths received from the U-boats.
5. Finally the headquarter sent message to the U-boats, the convoy position.

perhaps it was complicated, and requested constant radio communication, but was efficient. Ok, German coastal HF direction finding (DF) network ould to fix airlpanes' position by bearing of HF radio signals directly from the airplanes, but direction finding of HF is not so accurate as direction finding of MF signals.
On the other hand, by the system explained above, the headquarter was constantly informed of the situation, not just about the convoy position but also about all U-boats' positions, and it was important.

The allied direction finding possibilities were reduced by using "short signals" by the U-boats, and it was efficient as well. Not just direction finding of German U-boats on HF was difficult but also German messages were reduced on few groups of characters, so time of sending was reduced as mucg as it was possible.
The Kurier system of burst messages was excellent but came to late and actually never was introduced in service. But it is not important so much in the question about the wolfpacks.

Best regards!
Funkmeister