This year, the subject for the Duke of Edinburgh Lecture was chosen by the President and the Council as a result of recommendations made by the Educational Sub-Committee. Although the lecture was to be an individual contribution it was to have the full help and support of the Institute. Without this, the lecture would have been impossible, and therefore it seemed necessary to make acknowledgments at the outset.

Help has been given most freely and generously by many Fellows and Members, and in particular by the President, Professor A. Stratton, by Dr. G. E. R. Deacon, F.R.S., the Chairman of the Educational Sub-Committee, and its members, Captain C. H. Cotter and H. E. Smith, by D. H. Sadler, the Chairman of the Membership and Fellowship Committee, by Captain F. L. Main, a member of the Council, and by M. W. Richey, the Executive Secretary. Further invaluable suggestions came from many sources outside the Institute, notably from Dr. A. Clow of the B.B.C., J. A. Edgar of the Department of Education and Science, Dr. H. F. Huddleston of R.A.E., Farnborough, and Professor S. Sutherland of Sussex University. Finally, a very special word of thanks to B. W. Lucke, Schools Inspector, Liverpool. This paper owes a great deal to his ideas and to his inspiration.

I propose to discuss the problem of long-range navigation from the point of view of the A.T.C. system planner and to describe in outline the work that has been done in the North Atlantic Systems Planning Group (N.A.T.S.P.G.). In this area there are tidal flows of traffic of relatively high density and there is inevitably a need to reduce separations as much as possible, consistent with safety, to ensure operating costs are reduced, or at least kept in bounds with anticipated increases in traffic. This requires a much more precise definition of an acceptable separation standard, and for future planning the establishment of a relationship between separation standards and navigational capability.

Mr. Blake has given us an outline of what is needed in the context of Navigation of Long-Range Subsonic Transports in the 1970's. I now intend to pursue the theme by saying what I think v.l.f. navigation techniques can contribute to the solution of the navigation problem. In particular, I want to talk very briefly about the contributions that we feel v.l.f. might make towards the particular problem of limiting the numbers of aircraft which creep beyond Mr. Blake's navigation tolerance ‘fringe’ in addition to, possibly, by adding navigational information, increasing the effective M.T.B.F. of the total navigation system.

Clearly, addition of equipment cannot reduce M.T.B.F. in the narrow sense of the term—more equipment must have more faults—but if one interprets ‘fault’ as the incidence of a navigation error beyond the specified limit rather than narrowly as an electronic malfunction, I do think that v.l.f. navigation has its contribution to make to effective M.T.B.F.

In 1963, in addition to examining the characteristics of the Omega system, we were also very concerned with a comprehensive navigation system study which was designed to examine all aspects of a world-wide navigation system operating in a B.O.A.C. type environment. This concerned a study of dead reckoning as well as externally referenced sources of information. You have the choice of an all dead reckoning system probably employing multiple sensors of the same type, triple IN is typical, or you could have a mixture of externally referenced and self-contained, in other words dead reckoning sensors. Occasional reference could be made to short-range aids or even a satellite system if available to increase the integrity of the position-fixing information. The inertial and computer aspects have been examined by the Avionics Department at R.A.E. whereas the radio sensors, which are externally referenced, and the relevant software have been the responsibility of the Radio Department.

The ability to map terrain by means of an airborne radar raises many possibilities. Some few years ago it was recognized that a mapping radar which scanned to the side of an aircraft (rather than ahead) might, additionally, have important military potential. The research described here concerns the early operator evaluation of a prototype sidescan equipment which promised, among other things, to permit accurate fix-point navigation at lower flight altitudes.

By recent standards our aircraft was to progress at a fairly gentlemanly rate, somewhat below the speed of sound. Hence the radar map, produced as a moving strip by a rapid photo-development technique, did not threaten to flash past the navigator's eyes at an impossible speed. Nor, in general, did we expect the operator to be provided with anything unsatisfactory in the way of briefing. What is more, the navigator would be able to devote his undivided attention to the radar material whenever a fix-point was due.

This paper discusses some of the variations that occur in the Earth-ionosphere waveguide that can contribute to errors in the Omega lines of position that are used to obtain navigational fixes on a world-wide basis. Effects due to conductivity variations in the Earth's surface, night to day changes in the lower ionosphere, multi-mode propagation, and solar disturbances of the ionosphere are considered and attention is drawn to the use of the multiple frequencies transmitted in the Omega format to overcome some of these sources of error. The paper was presented at a Marine Navigation Symposium held in Sandefjord, Norway, on 24–26 September 1969 and is reproduced with the permission of the organizers. (Crown Copyright, reproduced with the permission of H.M. Stationery Office.)

This paper contains a brief survey of a series of instruments which have been developed for use in sailing yachts. It then outlines the principles of two computers; one navigational, the other for sailing performance indication. It does not cover radio navigational aids, echo sounding or radar. The data requirements are: 1. Navigational, comprising distance run through the water, heading, leeway angle. 2. Functional, comprising speed through the water, direction of the apparent wind and speed of the apparent wind.

For measuring distance run, the classical towed rotator type of log, fitted with a mechanical or electro-mechanical revolution counter has been largely superseded in racing yachts by logs employing through-hull sensors on account of drag considerations and the inconvenience of having to shorten the line when sailing slowly in shallow water. It still finds favour in cruising yachts on account of its generally lower price and its simplicity.

If the present Collision Regulations are defective, it is largely because the principles underlying them are not sufficiently developed for today's circumstances. In this paper Admiral García-Frías of the Spanish Navy attempts such a development and proposes a new set of rules, adapted to present circumstances, for vessels in sight of one another. These proposals, with the set of rules previously suggested in this Journal for restricted visibility using radar, form a complete system for avoiding collisions in both situations so that it would be easy to pass safely from one situation to the other when necessary, because of the unity of principles they present.

It is encouraging for certain schools of thought—which started some years ago advocating the revision of the Collision Regulations for occasions when radar was being used in restricted visibility—that there now seems to be a general dissatisfaction amongst seafarers with the lack of guidance provided in the rules. Consequently, they are at last interested in a fundamental review of the Regulations.

In the July number of the Journal there appeared a series of contributions on the revision of the Collision Regulations, preceded by an introductory note which referred to a number of the more important papers on this subject published in the Journal during the last ten years. Partly as a result of this series of contributions, and of a questionnaire recently circulated by the International Chamber of Shipping, Captain Thompson, Master of the S.S. Magara, after discussion with those concerned with the Rules on board his vessel, has drawn up, for general discussion, draft revised Collision Regulations. Naturally they depend heavily on ideas published in the Journal and elsewhere; indeed their particular value is that they take account of many of these ideas and attempt to express them in a practical and seamanlike fashion. Clearly there are loopholes in the draft: it is the work of seamen, not lawyers. What matters at this stage is the intention, which is to provide rules and a code of conduct which are simple, unambiguous and clear. Commander P. C. H. Clissold made some useful comments on the original draft.

Of those who took part in the discussion on the Collision Regulations published in the Journal (22, 285), some favour amending the present rules. and others refraining them completely. There are grounds for thinking that a similar dissension exists among seamen.

The introduction of marine radar into the general market immediately after the last world war, offered the promise of reducing the many economic losses sustained through failure to keep schedules during periods of reduced visibility. These promises have been only partially fulfilled. Initially it was accepted that radar needed little introduction—that it established the range and bearing of targets in the vicinity and no more was required. With radar available on only a small proportion of vessels, this limited information was sufficient to enable these few to avoid other, slower-moving craft which were not so fitted. Radar is now fitted on almost all vessels and speeds have increased, while manoeuvring characteristics have changed because of increased tonnage of vessels. The situation is now far more complex.

This paper was presented by the Executive Secretary at the twentieth anniversary convention of the Australian Institute of Navigation held in Sydney, New South Wales, on 10 and 11 October 1969.

In July this year two men landed on the Moon, certainly the most spectacular navigational achievement of mankind. It was a voyage backed by all the massive scientific resources of a modern industrial state, in which thousands of people were directly involved. The astronauts were a single link in a navigational loop employing a host of technologies.

Two hundred years previously James Cook had sailed on the first of his three great voyages, during which he discovered New Zealand and the coast of New South Wales. Cook was perhaps the most illustrious navigator of all times, even if perhaps he advanced the art more by force of character than by any specific contribution. When he started his voyages, the art of nautical astronomy was in its infancy. At their finish William Wales could comment, in 1788, that no officer who had been concerned with them ‘would not, whatever his real skill may be, feel ashamed to have it thought that he did not know how to observe for and compute the time at sea, though but a short time before these voyages…such a thing was scarcely ever heard of among seamen; and even first-rate astronomers doubted the probability of doing it with sufficient exactness’.

In this paper Commandant Oudet, who might well be called the architect of routing in the Dover Strait, discusses certain aspects of what has come to be known as the Sandettie problem, namely the emergence of a potential accident black spot at the north-eastern extremity of the one-way routes in the Strait. Various solutions are discussed, including the reversal of the direction of traffic flow in the Strait recently proposed by the Honourable Company of Master Mariners and supported by Trinity House. Commandant Oudet shows that this proposal, unless the direction of flow were reversed in adjoining traffic separation schemes, would have the effect of greatly increasing the number of crossings and encounters outside the Strait. ‘The remedy would be worse than the disease’, he concludes. ‘It would be better to abandon traffic separation altogether’.

Places where road traffic is particularly dangerous and congested are often referred to as accident black spots; and the term is beginning to be used in the same sense in a navigational context. At sea an excessive density traffic always involves danger, because it is impossible to build fly-overs, as on land, and so avoid crossings; all encounters and all crossings take place on the same plane.

A student of navigation who refers to the standard textbooks will be confronted with a multiplicity of sailings which are said to include plane sailing, parallel sailing, middle or mid-latitude sailing, mean latitude sailing, traverse sailing, short distance sailing using rhumb-line formulae, mercator sailing, great-circle sailing, approximate great-circle sailing, composite sailing and composite greatcircle sailing. To the student it may seem a reasonable assumption that so many differently named sailings are based upon as many different ways of taking a ship from one position to another, which is of course a nonsense.

The paper by Captain J. P. Stewart in the July issue of the Journal, entitled as above, presents a wealth of evidence and argument for the obvious sense of designing marine radars in such a way that they can:

(a) present compass stabilized radar pictures in the natural ship's-head-up orientation. This avoids the mental stress of trying to correlate the radar view and the eye-ball view of the same situation when the two may be presented in completely different orientations;

and

(b) simultaneously allow true bearings of targets to be read off directly.

It is to be hoped that before the Collision Regulations are revised in any sense that affects the rights and obligations of sailing vessels, people with practical experience of navigation under sail will be consulted. It looks as though their advice will be needed.

One increasingly hears, for example, that under modern conditions steam should no longer be required to give way to sail. ‘It seems quite unreasonable now’—Captain Dickson, for instance, expresses it in the last number of the Journal (22, 448)—‘to expect in most cases that sailing vessels should be required to stand on for power-driven vessels’. But the reason a power-driven vessel is required to give way to sail is not some kind of old world courtesy, but that if there is no wind, the sailing vessel is immobilized: it cannot give way.