chief mate vs gaffer

chief mate

noun
  • In the merchant navy, the officer who is second in command to the captain, and whose primary duties include managing the maintenance and upkeep of the vessel. 

gaffer

noun
  • A sailor. 

  • A chief lighting technician for a motion-picture or television production. 

  • The leader of a group or team, such as a boss, foreman, coach, publican. 

  • The baby in the house. 

  • An old man. 

  • A glassblower. 

How often have the words chief mate and gaffer occurred in a corpus of books? (source: Google Ngram Viewer )