A steamboat was a boat powered by steam.
On Earth, in the 1890s, Royal Mail Steamers were operated by the New Zealand Shipping Company, offering trips to New Zealand, Australia, Cape Town and Madeira from London and Plymouth. (TV: Deep Breath) Later steamboats included the Lankester (AUDIO: Cryptobiosis) and the SS Batavia, which were in use during the 20th century. (AUDIO: The Girl Who Never Was) By 1928, steamboats were common enough to have entered the public imagination, with a famous cartoon, Steamboat Willie, featuring Mickey Mouse operating one in his "first professional mouse job". (TV: Disney Time)
Steamboats also appeared on other planets. On Zazz the Sixth Doctor and Frobisher used the Sea Sharp when travelling to and from Professor Strut's island. (COMIC: The Gift)