gangboard vs porch

gangboard

noun
  • The boards ending the hammock-nettings at either side of the entrance from the accommodation-ladder to the deck. 

  • A board or plank used as a temporary footbridge between a ship and a dockside or any gap such as scaffolding. 

  • A board or plank placed within or without the bulwarks of a vessel's waist for lookouts to walk or stand on. 

porch

noun
  • A covered entrance to a building, whether taken from the interior, and forming a sort of vestibule within the main wall, or projecting without and with a separate roof. A porch often has chair(s), table(s) and swings. 

  • A portico; a covered walk. 

  • The platform outside the external hatch of a spacecraft. 

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