CC ), ▁previously ▁known ▁as ▁the ▁Command ing ▁Offic ers ▁Qual ifying ▁Cour se ▁( CO Q C ), ▁and ▁inform ally ▁known ▁as ▁The ▁Per isher ▁because ▁of ▁its ▁supposed ▁low ▁success ▁rate , ▁is ▁a ▁training ▁course ▁for ▁naval ▁officers ▁prepar ing ▁to ▁take ▁command ▁of ▁a ▁sub marine . ▁ ▁Cre ated ▁by ▁the ▁Royal ▁Navy ▁during ▁World ▁War ▁I , ▁the ▁course ▁was ▁originally ▁intended ▁to ▁address ▁the ▁high ▁attr ition ▁rate ▁of ▁sub marine ▁command ers , ▁as ▁the ▁previous ▁method ▁of ▁hand ing ▁down ▁knowledge ▁from ▁officer ▁to ▁officer ▁was ▁prevent ed ▁by ▁w art ime ▁death s . ▁Following ▁World ▁War ▁II , ▁the ▁Royal ▁Netherlands ▁Navy ▁became ▁involved ▁in ▁the ▁course ; ▁the ▁Dutch ▁later ▁partner ed ▁with ▁the ▁British ▁to ▁run ▁the ▁course , ▁and ▁following ▁the ▁British ▁conversion ▁to ▁a ▁fully ▁nuclear ▁sub marine ▁fleet , ▁took ▁over ▁responsibility ▁for ▁running ▁the ▁course ▁for ▁dies el - elect ric ▁sub mar ines . ▁Offic ers ▁from ▁other ▁nations ▁regularly ▁particip ate . ▁ ▁The ▁four - month ▁course ▁is ▁run ▁in ▁four ▁stages , ▁the ▁first ▁and ▁third ▁involve ▁learning ▁ash ore ▁in ▁sim ul ators , ▁while ▁the ▁second ▁involves ▁learning ▁at ▁sea . ▁The ▁fourth ▁phase ▁is ▁the ▁assess ment , ▁during ▁which ▁the ▁candidates ▁( of ▁which ▁the ▁maximum ▁is ▁six ) ▁show ▁their ▁ability ▁to ▁command ▁a ▁sub marine ▁una ided ▁during ▁war - like ▁conditions . ▁The ▁success ▁rate ▁for ▁the ▁SM CC ▁is ▁ 6 0 %