Originally Posted by
SamYeager
I believe you'll find the wolfpacks primarily operated on the surface up till mid 1943 as since they were faster than the convoy they had no problem keeping up with it. This continued until the widespread introduction of radar and air cover across the Atlantic forced them to submerge.
Yep. The most numerous type the Type VII were not true submersibles, in fact they were very agile boats on the surface, and could only go to a max depth of around 200-240m, and not for long periods either, so no way were they sitting silently on the bottom waiting for the convoys.