WW2 Allied passive sonar detection distances.

How far away could a stationary passive listening sonar detect a Type VII U-boat moving at 4 Knots? British gear in 1941 or 1942.
 
high frequency active sonars produced good chance of U-Boat detection @ out to maybe km? Passive detection was with hydrophone's that were no better range but much harder to detect U-Boats especially if drifting at 4 knots. I assume submerged target?
 
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