Bovril boats, also known formally as sludge vessels, were specially designed sewage dumping vessels that operated on the River Thames from 1887 to 1998. Their task was to remove London's human solid waste from Beckton and Crossness for disposal on the ebb tide at sea, at Black Deep, an extremely deep part of the North Sea fifteen miles off Foulness, on one of the main approaches to the Thames Estuary. Similar boats operated on the Manchester Ship Canal, the Tyne, and elsewhere.