[Rockin Robbins]

After radar is available, I don't submerge for sonar searches at all. For most patrol areas 75 mile radius is safe. If I recall correctly only one or two are 50 mile radius. I have used 75 all the time and had no trouble with any of my objectives. Don't make your search patterns too tight. There is no gain from searching the same area on successive sweeps that are too close together. Your goal is to cover the most ground in the least amount of time.