Black Deep
The Black Deep is a channel which forms the most important of the three main permanent shipping routes past the shoals in the North Sea and outer Thames Estuary, the others being the Barrow Deep and Princes Channel.
The Black Deep begins in open sea east of Foulness Point and south of Clacton-on-Sea and is bounded by two substantial sandbanks, the Sunk Sands to the north-west and the Long Sands spread out to the south and east (which have some wind turbines).
Deep-draught vessels making for the Port of London use it to approach (from the north-east from the position of the Sunk lightship thence into the Knock John channel to enter the Thames Estuary. Bulk carriers also tend to use the channel when entering or exiting the Medway estuary to the south that has a minimum depth of 14 metres as far as Kingsnorth.
Nautical markers
Deep-draught vessels making for the Port of London from the North Sea use it to approach (from the north-east from the position of the Sunk lightship thence into the Knock John channel to enter the Thames.