The steamboat Sultana was destroyed in an explosion on 27 April 1865 when one of its boilers exploded. The explosion was found to have been caused by mismanagement of water levels in the boilers and careening. Sultana was overcrowded and top heavy. As it traveled north following twists and turns of the river, it listed from side to side. Sultana's four boilers were mounted side-by-side and interconnected, so when the ship listed sideways water would run out of the highest boiler. When Sultana listed the other way, water pouring back into the empty boiler would hit hot spots and flash into steam, creating a surge in pressure. With modifications, the Sultana might have become the World's first, largest and loudest of all pop-pop boats.
Go to http://en.wikipedia.org/wiki/SS_Sultana#The_tragedy
if you prefer the official story of what happened.