SS Great Western of 1838, was a wooden-hulled paddle-wheel steamship with four masts, the first steamship purpose-built for crossing the Atlantic, and the initial unit of the Great Western Steamship Company. She was the largest passenger ship in the world from 1837 to 1839, the year the SS British Queen went into service.

A paddle steamer is a steamship or steamboat powered by a steam engine that drives paddle wheels to propel the craft through the water. In antiquity, paddle wheelers followed the development of poles, oars and sails, where the first uses were wheelers driven by animals or humans.