The Marchioness disaster was a fatal collision between two rivercraft on the Thames in London on 20 August 1989, drowning 51 people. The pleasure boat Marchioness sank after being pushed under by the dredger Bowbelle, late at night near Cannon Street Railway Bridge. A formal inquiry blamed poor lookouts on both vessels, and inadequate instruction of both crews. Four new lifeboat stations were later installed on the river.