These methods were briefly described in the Journal (Vol. 13, No. 2). They were prefaced by some comments designed to draw a comparison between the air and sea problems and collision rates. Statistics are liable to be misleading if not perfectly understood and definitive, and marine collision statistics as much as any. It should be realized that Lloyd's List figures include almost every collision incident to ships of joo tons and over and that a comparable air figure would probably need to include damage to aircraft by aircraft on airfields and in hangars and whether under their own power or in tow.

Recent articles in this Journal will have suggested that there is a conflict between certain mathematicians and certain mariners on the subject of the efficacy of the Collision Regulations. The controversy is really philosophic rather than mathematical and, although it would never be suggested that the mathematical system we have seen is anything but flawless in isolation, there are grave doubts that it would work, even on a planet composed solely of deep water and supporting ships staffed only with mathematicians, having collision avoidance as their single preoccupation.

In a recent paper on shipborne radar the authors tried to analyze the mental approach of a master or pilot to the problem of handling his ship in a confined space when berthing in fog. The sense of loss that is caused by the absence of direct vision was referred to and various means by which confidence and control might be restored in these circumstances were considered. In that paper only the inadequacies of present-day shipborne radar in meeting these requirements were discussed. The approach to the problem can, however, be broadened to include the whole question of port operation in fog, and the present paper attempts to describe the general requirements and to consider in particular the role of shore-based radar and the manner in which the information obtained from radar or other aids should be presented to the master.

Recent correspondence in the Shipping Press brings to mind many of the sayings, writings and judgments of the last 10 years and stimulates thought once more in search of some basic weakness in the partnership between the seaman and his radar which, all too often, turns the risk of collision into the fact. Re-examination of the circumstances of some of the better annotated and sometimes more publicized cases is frustrating, partly because of the lack of personal detail in the evidence and partly because some of the conclusions which may be drawn point to failure of bridge personnel to understand the obvious fundamentals and so suggest that there must be undisclosed and more complicated causes. This latter, it is believed, is debatable.

However misleading statistics may be, they often make an interesting study and those of marine collisions are no exception. In Volume 13 of thisJournal, page 430, some figures were given for collisions in fog with radar, which permitted the conclusion that, in North-west European waters in 1959, each day of fog produced 1·2 collisions. Up to and including 1959 this figure was not rising significantly.