The use of radar in relation to the Rule of the Road at sea is a subject over which there is still a great deal of controversy. An examination of the main problems involved was made in this Journal (Vol. 3, No. 1, January 1950) by Captain F. J. Wylie who concluded in his paper that the use of radar might justify a more liberal interpretation of the term ‘moderate speed’ than has hitherto been countenanced; and a recent amendment to the King's Regulations and Admiralty Instructions clearly accepts the use of radar as an existing circumstance within the meaning of Article 16.

No attempt, however, has so far been made to arrive at a precise definition of ‘moderate speed’, and it may well be that the reasons which prevented a definition being made in the non-radar case are in fact given more force when radar, with its added variables, is used. On the other hand it is unlikely that any progress in the matter can be made without a full discussion of the factors involved, and Captain Robb's paper, though it may be possible to dispute some of his conclusions, is presented here as an interesting attempt to achieve a definition which can serve as a guide to shipmasters.—Ed.