gangboard

noun

• (nautical) A board or plank used as a temporary footbridge between a ship and a dockside or any gap such as scaffolding.
• (nautical) A board or plank placed within or without the bulwarks of a vessel's waist for lookouts to walk or stand on.
• The boards ending the hammock-nettings at either side of the entrance from the accommodation-ladder to the deck.