The British-born actor William Chapman built the first showboat, the "Floating Theatre" (14 by 100 feet) in Pittsburgh in 1831.  He and his family floated from landing to landing, playing dramas such as William Shakepeare's Taming of the Shrew with music and dance specialties.  Upon reaching New Orleans late in winter they junked the boat and returned by steamer to Pittsburgh to repeat the pattern the following year.  One unusual example of a popular showboat of this early period was the Floating Circus Palace of Spaulding and Rodgers built in 1851 that featured large scale equestrian spectacles.  By the mid 19th century, showboats were seating up to 3,400 and regularly featured wax museums as well as equestrian shows though because of the Civil War they disappeared entirely. 

When showboats were revived in 1878, they specialized in vaudevile and melodrama.  The steam calliope greatly increased audiences. Such boats as the Water Queen and the Princess plus dozen of others with seating capacities of 100 to 300 carried their rich cargoes of humor, music and simple entertainment on every river of the Ohio-Mississippi system from the narrow Monongahela in the Northeast to the bayous in the South. 

With the disappearance of river frontier conditions in the 1900s and with the coming of better roads, automobiles and motion pictures, the number of showboats declined.  To compete with land entertainment, they became larger and more elaborate.  

The last showboat to travel the rivers was a showboat called the Golden Rod in 1943.  Its glory days are recalled by the Majestic, which today performs in Cincinnati during the summer months.

The showboat, Majestic being pushed by Attaboy

A showboat was a floating theater that traveled along the waterways of the United States bringing culture and entertainment of the inhabitants of river frontiers.  Showboats were a special type of riverboat designed to carry passengers rather than cargo and they had to be pushed by a small towboat also known as a pusher which was attached to it.  Showboats were rarely steam-powered because the steam engine had to be place right in the auditorium for logistical reasons therefore making it difficult to have a large theater.

As I see it, showboats which provided live entertainment on water were the predecessors to floating stages that provide live entertainment on water, as well.  

Lake Compounce in Bristol Connecticut

Pat Locke