in 1939 - 1940 a lot of Anti submarine warfare technology was left over from World War One... but then again so was a lot of Submaring technology too.
evading the escorts will be easier in this early part of the war, but you will notice that it is fairly easy to be detected.
try to mount your attacks under the following conditions
1. Night - your vision is impared but so is visual detection by enemy ships!
2. Rough Seas - If you have heavy sea swells little "hills" are created for your boat to hide behind, also more background noise causes enemy sonar equipment to have greater difficulty in detecting you
3. Slow Speed - the slower you go the less engine RPM you are turning out the less noise you are making (2 kts or less)
your approach should always be from ahead of the convoy and off to one side without going near any escorts. i rig for silent running and ride at 60 meters until its time to pop up to PD and attack.
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