accommodation ladder vs gangplank

accommodation ladder

noun
  • a flight of stairs or a ladder for lowering over the side of a ship for access to and from a small boat. 

  • The property ladder, without the implication of necessarily owning the place where one lives. 

gangplank

noun
  • A board used as a temporary footbridge between a ship and a dockside. 

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