The PS Waverley, the world's last seagoing passenger paddle steamer, at the pier in Oban.

NOTE that it is often assumed that the "SS" in the name of many ships (e.g. the SS Titanic, or the SS Queen Mary) stands for Steam Ship, but it doesn't. It stands for "Screw Ship", to distinguish those powered vessels propelled by a propeller (or "screw") from those propelled by paddles, such as the PS Waverley.