flagship vs sea captain

flagship

noun
  • The ship occupied by the fleet's commander (usually an admiral); it denotes this by flying his flag. 

  • The most important one out of a related group. 

  • The ship regarded as most important out of a group, e.g. a nation's navy or company's fleet. 

verb
  • To act as a flagship for. 

sea captain

noun
  • The captain of a ship, as distinguished from a captain in the army. 

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