dinghy vs passenger ship

dinghy

noun
  • A small open boat, propelled by oars or paddles, carried as a tender, lifeboat, or pleasure craft on a ship. 

  • An inflatable rubber life raft. 

  • A sailing dinghy. 

verb
  • To travel by dinghy. 

passenger ship

noun
  • A ship whose primary function is to carry passengers. 

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