sentences:  Bovril boats
  
  Bovril boats, also known formally as sludge vessels, was the nickname given to 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 located fifteen miles off Foulness, on one of the main approaches to the Thames Estuary.