portage vs towing

portage

noun
  • An act of carrying, especially the carrying of a boat overland between two waterways. 

  • The route used for such carrying. 

  • The wages paid to a sailor when in port, or for a voyage. 

  • A charge made for carrying something. 

  • Carrying capacity; tonnage. 

  • A porthole. 

verb
  • To carry a boat overland 

towing

noun
  • The act by which something is towed. 

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