Marketing a marine radar may not sound the most promising subject for a navigational paper. But in an age when almost anything is technically feasible, the direction of progress will be governed by many considerations which, if they are not themselves navigational, are nevertheless of great interest to those concerned with the subject. A new range of equipment for example must be related to the level of skill and training which actually prevails at sea; research and development costs must be seen in relation to the cost-effectiveness of the system; and finally purely operational factors such as traffic separation schemes may have to be taken into account. In this paper, originally presented in Paris to the French Institute of Navigation, some of these considerations are discussed in relation to the new Decca anti-collision radar.

Just over 25 years ago, in the summer of 1944, a United Kingdom conference on radio for marine transport concluded that radar would be of great value to merchant ships. They asked the Royal Navy to draw up a specification for the average ship. Discussion with various shipping interests confirmed that there was in fact a requirement for a radar set ‘for navigation and pilotage as distinct from a collision warning set, which would, of course, be a much simpler and cheaper device’. The later 1946 Ministry of Transport Specification referred to the requirement ‘to provide warning of the proximity of other surface craft and obstructions which will enable collision to be avoided’. Now of course, after 25 years of hard experience, we know that the matter of avoiding collision at sea is not apparently so simple.