When the Offshore Powerboat Race was first held in 1961, navigators made the painful discovery that conventional methods of coastal pilotage were useless in a comparatively light, high-performance powerboat being driven to its limit.

Taking part in the race is like driving a Mini-Cooper over a frozen ploughed field in intermittent fog from London to York, the same distance as the course from Cowes to Torquay. Chart-work is out of the question. It is physically impossible to lay off a bearing or read a course. Furthermore, the figures and symbols are too small to be read, and, as often as not, the chart gets blown overboard. Radio bearings are unobtainable over the engine interference. A hand-bearing compass cannot be held steadily enough. Parallel rulers, dividers, pencils and the navigator's notebook end up in the bilges.