The ship's gangway connects the vessel to the dock. Merchant ship gangways generally take the form of a stairway.
The gangway connects the ship to the dock. It is used for the embarkation and disembarkation of passengers, crew, pilots, etc.
There are many different types of ship's gangway. Cruise ships use short, broad platforms for embarking and disembarking passengers. There are spiral models whose configuration varies with angle of use. Some gangways fold for stowage within the sides of the ship.
The gangway's designated function will determine choice. Port characteristics should be considered, as well. In ports with great tidal range, the angle of the gangway and its steps are important factors.