Why submarine commanders now get a second Perisher attempt

Was it worthwhile to deny Perisher candidates a second chance and remove them from the submarine force?

A selective second chance is worthwhile when the failure is recoverable; a failure that shows unfitness for command should still end the attempt.

The original refusal of second chances reflected a sink-or-swim approach to submarine command. A failed candidate can now receive another attempt if the failure does not demonstrate a fundamental inability to command. Some failures remain disqualifying regardless of the demand for officers. Perisher still requires candidates to run a nuclear submarine in a wartime scenario without functioning computers. Much of its difficulty comes from maintaining command and doing the necessary work mentally when those aids are unavailable.