[Rockin Robbins]

Is the task force on the other side of the destroyer? Are you on a parallel course and they are at a bearing of 90º? What is your relationship to the convoy? How many escorts? How many merchies? What is the shape of the formation? What kind and how many torpedoes do you have? What is the date? What is your battery status? Are you in a Fleet Boat or a U-Boat?

The outer circle is visual detection range, the inner circle with the rear-facing wedge missing is his approximate sonar range.