cockboat vs inflatable

cockboat

noun
  • A small rowing boat, especially one pulled behind a larger ship, or used to ferry goods between a ship and the shore. 

inflatable

noun
  • A boat or dinghy that may be inflated when needed. 

  • Any other structure, artwork etc. that is inflated. 

adj
  • Able to be inflated or blown up. 

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