The typical technique used for all patrol missions is to zoom in on the mission location icon on the Nav map. Use the circle draw tool and create a circle centered on the icon with a radius of 50 miles. Cruise around inside this circle for 24 hours or more until the icon changes to grey and the message in the F12 window shows accomplished. I've never had to wait more than 4 days so far. You may have to refresh the nav map several times to see the icon change color. What you do with the time spent there is up to you. I sink what I detect and make note of the aircraft traffic (where it comes from and goes to) which may indicate a base or carrier in the direction where the planes return route appears to converge. If you venture outside the circle, the timer resets which adds time time to the procedure.
After that you are free to venture around. If you call in after the icon changes, you will likely get another mission sent to you until your torpedoes run out.
-Pv-
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