The problem of collision-avoidance at sea by means of radar is constantly under discussion in maritime circles within the U.S.S.R. This paper, and that of Captain Bukhanovski (Journal, 20, 247,), describe one direction of research that has been actively pursued in the Soviet Union.

The device described was developed by the Central Scientific Research Institute for Water Transport for the Ministry of Merchant Marine and sea trials were carried out in the Black Sea during the summer of 1962. The present paper describes the principles of the device and the performance during trials. It has been prepared for publication in the Journal in collaboration with Captain G. Shoomayko.

Articles on the prototype have appeared in Morskoi Flot (no. 122, 1959, no. 2, 1964), Die Seewarte (Hamburg, October 1961) and Navigation (Paris, July 1962).