#watch.work_shift  a period of time (4 or 2 hours) during which some of a ship's crew are on duty
  supertype:  #work_shift__shift__duty_period  the time period during which you are at work
  subtype:  #dogwatch  either of two short watches: from 4-6 pm or 6-8 pm
  subtype:  #graveyard_watch__graveyardwatch__middle_watch__midwatch__night_watch__nightwatch  a watch during the night (as from midnight to 8 a.m.)

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