grappling iron vs thole

grappling iron

noun
  • A metal hook, attached to the end of a line, used to hold two ships together. 

thole

noun
  • A pin in the side of a boat which acts as a fulcrum for the oars. 

  • A pin, or handle, of the snath (shaft) of a scythe. 

  • A cupola, a dome, a rotunda; a tholus. 

verb
  • To endure, to put up with, to tolerate. 

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