clamping vs grapnel

clamping

noun
  • The act by which something is clamped. 

grapnel

noun
  • A device with a multiple hook at one end and attached to a rope, which is thrown or hooked over a firm mooring to secure an object attached to the other end of the rope. 

  • A grappling iron. 

  • A small anchor, having more than two flukes, used for anchoring a small vessel. 

verb
  • To connect (ships) with a grapnel. 

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