Portable Pilot Units. They don’t immediately sound the most exciting things, but they are proving invaluable aids for pilots bringing large ships on to the Thames, and they were deployed when the nearly 400-metre long Edith Maersk recently became the biggest container ship ever on the river.

A Portable Pilot Unit (PPU) is a laptop type unit which brings together electronic charts, other safety and navigation information, with precise positioning data to help pilots with on-board decision-making. The PPU is linked to two Global Positioning System (GPS) pods placed on either wing of a

ship’s bridge. Together they pinpoint exactly where the ship is in the navigation channel, in real time. On the larger ships this gives the pilot a view of any ‘swinging’ (movement of the boat’s bow or stern), before the human eye can see it and identifies precisely where the tugs are positioned.

PLA’s director of marine operations, Peter Steen explains: "This technology moves up a gear by providing the pilot with precise information that helps in manoeuvring decisions. It is particularly helpful in tight turning situations."

The information from the GPS/navigation pods is combined with data from a specialised (real time kinematic) aerial to improve locational accuracy.