Just to clarify, The CO and his 1st Lt must have both completed and passed the Perisher. It is a test of leadership, command and control. If for whatever reason your teacher decides that you haven't made the grade, then the Master at Arms knocks on your cabin door with a bottle Scotch and you pack your bags. If you complete the Perisher, then your next assignment is as a Jimmy on another boat. If you fail you are rejected and you have to find another career. In the Navy or out. Everyone understands that from day 1.