coracle vs periagua

coracle

noun
  • A small circular or oblong boat made of wickerwork and made watertight with hides or pitch, propelled and steered with a single paddle and light enough to be carried on a person's back. 

periagua

noun
  • A large keelless flat-bottomed boat for shoal-water navigation, decked at the ends only, propelled by rowing, or by sails on two masts capable of being struck. 

  • Any small boat. 

  • A vessel made by cutting a canoe in two lengthwise and inserting a large plank. 

  • A dugout canoe. 

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