Work out how long at your speed (9.5knots) will it take to get to your waypoint.
Make notes with supermarks
Draw legs and set headings to your patrol area. "Auto fix" will keep posting your position on the map.
As you get closer to patrol area, start using "No Station Search for Real Nav" You must go below to use as the boat will auto dive.
When you start hunting your area, switch to " At Station Search"
Sink lots of ships