As a watch-keeping officer on ships daily crossing the North Sea and English Channel 1 was interested to read Commander Paton's paper on ‘Navigation in the English Channel and the Southern North Sea’ in the January 1978 issue of this Journal. Since the introduction of the traffic separation schemes many of us have been concerned about the possibility of an accident whilst crossing the lanes. It is an almost nightly experience to have ‘near misses’ and occasionally more than one ‘near collision’ inside the hour, with people who appear to think that, because they are in a traffic lane and going the right way, everyone else must keep clear of them. No attempt is made to avoid crossing vessels in accordance with the Collision Regulations and, in spite of flashing the warning five shorts and blowing five shorts on the whistle, we often have ships call us to demand we keep out of their way, contrary to all regulations, and frequently forcing us to take drastic evasive action.

The provision of Rule 10 of the 1972 Collision Regulations, that if vessels are obliged to cross traffic lanes they shall do so as nearly as practicable at right angles to the general direction of traffic flow, would appear to be simple enough. Could it be however that in areas of high traffic density, such as the Dover Strait, the theoretical simplicity of the right-angle crossing introduces problems of its own?

Crossing the Dover Strait several times a week, I am constantly alarmed by the apparent lack of regard for Rules 15 and 16 by vessels using the traffic scheme (The rules governing crossing situations and action required by the give-way vessel). I accept that some vessels using the lane believe, albeit incorrectly, that they have the right of way, but feel that a large proportion of these ‘port-side charlies’ are the result of the right-angle crossing.

Because of the pattern of traffic the speed of crossing vessels in the Strait is generally considerably greater than that of vessels using the lanes. Under the present Regulations a situation frequently arises in which a vessel using the lane finds herself as the give-way vessel to another six points or more on her bow. An initial reluctance to alter course by this amount is followed by the thought that there is not sufficient sea-room in which to alter, and the give-way vessel stands on.

Many runways lack an ILS/GS but have DME on the centre line (e.g. Lagos R/W 19) and DME can provide information in conjunction with the pressure altimeter to define a glide slope. For Lagos R/W 19 I have developed a method of calculation and have tried out the resulting table on two occasions. The pilot not flying the plane consults Table 1 and calls out deviations above or below the glide path (which meets the sloping runway 1500 ft from the threshold for a DC-10).