In 1948, the port of Liverpool was probably the pioneer of European VTS, when they set up a radar station, in order to facilitate the boarding of pilots from the cutter. In 1951, Long Beach in California established a radar and VHF to facilitate port operations. Le Havre established another system and so, gradually, other ports followed. At this time commercial radar was comparatively new, and made it possible for the first time, under almost all weather conditions, to observe vessel traffic from the shore. In combination with VHF radio, a traffic surveillance system was achieved and real- time information exchange between the shore and ships became possible. Nevertheless, it was not until 1985 that the role of VTS in connection with navigation safety, traffic efficiency and environmental protection gained international recognition. This recognition is contained in an IMO resolution, which constitutes the VTS guidelines.

In the May 1997 issue of the Journal, a paper on this subject was presented by Captain Turner on behalf of the General Lighthouse Authorities. I read the paper with interest, and in general concur with their assessment of the situation. However, I think that the situation regarding visual Aids to Navigation (AtoN) needs further consideration.

Among the many primary causes which lead to a shipping casualty, those of wrecking, stranding or coming into contact with fixed coastal structures depend (although not exclusively and only under specific conditions of visibility) upon the efficiency of the lighthouse and navigating lights network of a national coastline. The analysis of the shipping casualties involving Greek ships in the Greek seas revealed that, despite the recent introduction of sophisticated navigating aids for the prevention of stranding and contact, the share of the corresponding casualties remains unchanged. It appears that for coastal shipping operations, and in particular for port approaches, the traditional light navigating aids are and will always provide an irreplaceable safety service for navigators. This is mainly attributed to their technological simplicity which offers a high level of signal reliability and friendliness for the navigator.

Air Vice-Marshal Wilfrid Oulton, who died on 31 October 1997, aged 86, was one of that select group of distinguished Royal Air Force pilots who became equally distinguished navigators. Much of his early Service experience in World War II was spent in Coastal Command, where his natural flying ability combined with his acquired navigator's knowledge and skill led to exceptional operational achievements.

In 1943, German submarines were taking a devastating toll of Allied shipping in the North Atlantic and Wilf Oulton was flying long-range patrols over the Bay of Biscay. In May of that year, commanding a Halifax bomber which had been converted for maritime operations, he attacked with depth charges and sank two U-boats and shared in the destruction of a third. For these outstanding successes, which helped mark the Battle of the Atlantic turning in our favour, he was awarded the DSO.

Later, and completely different, with the cessation of hostilities, Oulton was jointly responsible for the introduction of the first Air Traffic Control system at Heathrow. And, different again, his ability to inspire confidence and co-operate extremely well with others led to the most challenging peace-time appointment as Joint Task Force Commander of ‘Operation Grapple’, which supported the British hydrogen bomb tests at Christmas Island in the Pacific Ocean.

Many problems in navigation can be best viewed and solved as problems in analytical geometry. We only need to understand the geometry of two ‘navigable’ surfaces; the sphere and the ellipsoid of revolution. The ellipsoidal model is generated by revolving an ellipse about its minor axis and this model is used as a global model for the surface of the Earth. The eccentricity of the meridian ellipse is small (≈0·082) so we sometimes refer to this surface as a ‘spheroid’ since the surface is still ‘sphere-like’. The physical Earth is, in fact, referred to as a ‘geoid’ whose surface is that which approximates global mean sea level. The mathematical representation of the geoid is not trivial and the ellipsoid of revolution is an extremely good approximation to it.

Much has been written on the subject of aircraft collision risk and avoidance over the past 50 years. As a particularly interested aviator (a military and civilian pilot for the last 32 years), with a limited memory for the mathematics I studied at school, I have read several of these treatises with interest. I do, however, feel that the advent of modern, accurate navigation systems has changed the distribution of collision causes radically. We should be concentrating, not on the risks of aircraft accidentally flying into each others' paths, but on the risks of them deliberately doing so.

That statement requires explanation, of course. There is a risk of one pilot deliberately and willingly putting his aircraft in the path of another (a terrorist or suicide for example), but the risk is considerably less than that of a pilot who does it unwillingly, but equally deliberately.

The 1997 International Conference of The Royal Institute of Navigation was held at Church House, Westminster, London on 11 and 12 November 1997. The full proceedings, which includes the following papers, can be obtained from the RIN Director (£40 to Members, £60 to non-Members).

Pike has pointed out the increasing risk of collision resulting from the expansion of the fast commercial vessel fleet and has made some proposals for alleviating the problems. This paper points out some difficulties with Pike's proposals and suggests, instead, a simpler modification of the philosophical basis of the colregs which would equally alleviate the greater risks of collision introduced by higher speed craft.

I understand that The Netherlands are pressing the IMO to change the COLREGS so that high speed craft (HSC) have the obligation of keeping out of the way of other vessels.

There is an IMO definition of high speed craft which was adopted by resolution MSC 36(63) in May 1995. It is the International Code of Safety for High Speed Craft. It covers vessels on international routes but does not cover, for instance, warships, troopships, fishing and pleasure craft. However, for the purpose of the COLREGS, I am sure that this definition should be widened and then incorporated.

I agree with many of the points in Mr R. D. Pike's article printed in this Journal in May 1997.