[banryu79]

I have recently return to Wilhelmhavens after completition of my very first patrol (1939). My assigned grid patrol was BF13, around the western approaches (I was lucky).

My patrol strategy was this:
- I defined a "patrol box" of about 200x90 Km centered on my patrol zone.
- I defined a saw-like "patrol course" with many waypoints.
- The saw-like patrol course was left-to-right or right-to-left depending on what my current location was with respect to the patrol zone itself (i.e. if I was on the right side I plotted a right-to-left oriented patrol course).
- The course was made of vertical legs alternated with diagonal ones.
- Each diagonal leg spanned along 25 Km in the horizontal direction with respect to the patrol box defined.
- I marked 3 equidistant spots along each diagonal leg; 2 along the vertical ones.
- The sposts on the diag and vertical legs were choosen in a way that maximized the area covered (I did try to not overlap them much).
- At each of the 3 spots on the diag leg I go to 30/20m deep and run silent for 2 hours.
- At each of the 2 spots on the vertical leg I go to 30/20m deep and run silent for 3 hours.
- When surfaced I run at ahead std till the next spot.
- In the rare case I'm able to compete the whole run without detecting contacts (never happened, in the worst case I have experienced I was able to run almost half of it, in about 2 days or little more) I plot another one in the opposite direction, rinse and repeat.

My patrol ended with 13 ship sunk, 10 of which detected and engaged in 8 days during this exercise.