boat shoe vs tennis shoe

boat shoe

noun
  • A type of casual footwear resembling a loafer, originally designed to be worn aboard a boat, characterized by water-resistant hide, soles designed to improve hold on wet deck of the boat and side lacing. 

tennis shoe

noun
  • A specialty sports shoe designed for playing tennis. 

  • A sneaker (trainer). 

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