navigator vs shipmate

navigator

noun
  • A sea explorer. 

  • A device that navigates an aircraft, automobile or missile. 

  • A person who navigates, especially an officer with that responsibility on a ship or an aircrew member with that responsibility on an aircraft. 

  • A user interface that allows navigating through a structure of any kind. 

shipmate

noun
  • A fellow sailor serving on the same ship as another. 

  • Any sailor (when used as a form of address by a sailor). 

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