Marchioness Disaster

Date: August 20, 1989 • Location: Canvey Island, United Kingdom

After colliding with the dredger Bowbelle on the River Thames in London, the pleasure boat Marchioness sank in thirty seconds, killing 51 people.

Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features; reshaping land and water features to alter drainage, navigability, and commercial use; constructing dams, dikes, and other controls for streams and shorelines; and recovering valuable mineral deposits or marine life having commercial value. In all but a few situations the excavation is undertaken by a specialist floating plant, known as a dredger.