ul ators ▁at ▁Den ▁Hel der . ▁The ▁second ▁stage , ▁known ▁as ▁CO CK EX ▁( a ▁cor ruption ▁of ▁the ▁old ▁CO Q C ▁name ▁plus ▁the ▁standard ▁sh orth and ▁for ▁exercise ), ▁takes ▁the ▁candidates ▁to ▁sea , ▁where ▁they ▁pract ise ▁the ▁skills ▁learned ▁in ▁the ▁sim ul ators , ▁along ▁with ▁tact ical ▁safety ▁training . ▁They ▁return ▁to ▁the ▁sim ul ators ▁for ▁stage ▁three , ▁where ▁they ▁are ▁taught ▁both ▁the ▁tact ical ▁aspects ▁( including ▁rules ▁of ▁eng agement , ▁ev asion ▁measures , ▁and ▁inter ception ▁procedures ) ▁and ▁personnel ▁management ▁skills ▁( including ▁stress ▁management , ▁maintain ing ▁working ▁conditions , ▁and ▁medical ▁skills ) ▁of ▁command ing ▁a ▁sub marine , ▁while ▁learning ▁other ▁skills ▁required ▁for ▁command . ▁On ▁conclusion , ▁the ▁students ▁return ▁to ▁sea ▁for ▁the ▁' C ock f ight ', ▁where ▁Te acher ▁evalu ates ▁each ▁sub mar iner ' s ▁ability ▁to ▁command ▁a ▁sub marine ▁independently . ▁During ▁this , ▁the ▁candidates ▁will ▁be ▁run ▁through ▁multiple ▁war - like ▁exer cis es ▁with ▁little ▁resp ite ▁between ▁each . ▁One ▁example ▁of ▁the ▁type ▁of ▁exercise , ▁from ▁the ▁ 2 0 0 4 ▁course , ▁required ▁the ▁candidate ▁to ▁take ▁his ▁sub marine ▁into ▁a ▁har bour ▁( sim ulating ▁a ▁naval ▁base ) ▁to ▁lay ▁mines , ▁with ▁less ▁than ▁ ▁of ▁clear ance ▁between ▁the ▁fin ▁and ▁fer ries ▁passing ▁overhead , ▁and ▁even ▁less ▁distance ▁between ▁the ▁ke el