A qualified, experienced captain with detailed knowledge of
local waters, who helps the master of a ship negotiate those waters. Pilotage
is compulsory for big ships in some harbours and their approaches. Private
pleasure craft take a pilot only when they choose to. Fly flag G if you need a
pilot – and can afford him.

(or pilot book) A book of pilotage instructions or sailing directions for particular waters. Either government publications, prepared for shipping by bodies
such as the United States Defense Mapping Agency (or the US Army Corps of
Engineers for the Great Lakes), and by the Hydrographer of the Navy in Britain,
or by commercial ventures specially suited to yachtsmen.