In many critical areas today navigation is more concerned with maintaining the flow of traffic than with finding the way. In his Presidential Address, which was presented at the Annual General Meeting of the Institute in London on 14 October 1970, Mr. Stratton discusses some of the characteristics of sea and air traffic systems and how they interact with the costs and benefits to the community as a whole.

In my previous address I concentrated on the way in which new scientific principles have been applied to determining the basic quantities of position, course and speed as inputs to the navigation process and with some of the technological problems encountered. The science and technology of navigation, however, are but the means by which navigation fulfils an operational task which itself is directed at the safe and expeditious movement of passengers and goods or to some military ends. In this address I will concentrate on some of the current and future operational tasks for navigation on the sea and in the air in fulfilment of the commercial need to transport goods and passengers and of the personal use of the vehicle for transport and leisure.

Marine traffic engineering is defined as the study of marine traffic and the application of such studies to improvements in navigation facilities and traffic regulation. The authors review recent Japanese work in this field.

Since the mountainous terrain of Japan hindered the development of road transport, goods have mainly been sent by ship, from the earliest times until the end of the last century. The rapid economic recovery of Japan after the Second World War owes much to the industrial belt along the coast which may be called the ‘Water Megalopolis’, with more than 70 million inhabitants. Shipping provides the greater part of both interzonal and international transport and consequently there is severe traffic congestion, accentuated by the presence of more than 200,000 fishing vessels.

The collision, in October 1970 in the English Channel, between the Liberian registered tankers Pacific Glory and Allegro may be thought to have brought an element of timeliness to the arguments advanced in this paper in favour of an international disciplinary court of justice and international standards for certificates of competency.

Dr. Buzek is both a Master Mariner and a Doctor at Law; Captain Wepster, the Institute's gold medallist for 1970, is with the Holland America Line.

In a speech before the seventh meeting of the Cultural Council of Europe, Dr. Mansholt expressed the opinion that in our highly industrialized western world, the time has arrived when environment is of equal importance with economy. On a world-wide scale we need general agreements on acceptable noise levels and pollution, with binding rules for industry, transport and agriculture as well as international control on the observance of these rules.

Digiplot is a marine radar aid for automatic anti-collision navigation which processes signals from conventional radar and presents computed information on a separate screen to give at-a-glance situation appreciation. The company's origin is touched on and conception and design are described as they evolved to meet operational requirements.

The majority of sophisticated radar equipments and devices available today have evolved from successive shipborne radar developments over a considerable period of years. With Digiplot it is otherwise. The Iotron Corporation was established in 1969 by a few men whose background had been information technology in the realms of fire control and navigational systems for submarines, aircraft, missiles and spacecraft, and reconnaissance systems using electronic and optical techniques; in all these systems digital electronics played a key role. The choice of the navigational functions of marine radar as the most appropriate subject for attention by the group was made after a general study of the commercial field, because of the revolution apparent in ships, their equipment and their operations.

In this paper, a version of which appeared in the October 1969 issue of the periodical Schip en Werf, Mr. Anneveld, who is the nautical adviser to a Dutch firm of marine solicitors, investigates the drift velocity and drift angle due to coriolis force on a vessel of a given size. He shows that these effects are not inconsiderable for large vessels operating in middle and high latitudes and may become of practical importance, particularly when berthing or navigating in the proximity of other vessels.

Captain A. Vreugdenhil first drew attention in 1955 to the effect of coriolis force on a moving vehicle and on ships in particular. Since then ships have increased greatly in size and as the coriolis force increases with the mass of the vehicle it may be useful to investigate the effect on the mammoth ships of today.

In the existing Steering and Sailing Rules there are seven classifications of vessels for assignment of responsibility in the open sea. Three of these classifications (Rules 18, 19 and 24) are based on the bearing criterion, two (Rule 17) on the wind bearing criterion and two (Rules 20 and 26) on the hampered vessel criterion. The only classification of vessels implied in the present writer's collision system is based on the bearing criterion. The object of this paper is to show that it is also possible to establish a single classification based on a turning criterion which offers some advantages over that based on the bearing criterion.

The problem of avoiding collisions at sea, particularly in restricted visibility, is not likely to have one simple solution. Indeed there are three main areas which need separate consideration because of their different requirements. First, in rivers and estuaries, port approaches and narrow passages traffic is rigidly confined. Second, in waters adjacent to coastlines and in some other areas dense traffic has limited space in which to manœuvre. Third, in the open sea there are fewer encounters and unlimited manœuvring space. It seems probable that the best solution to the first of these problems will be found in shore surveillance of the traffic and regulation of the traffic flow by a licensed authority. Prescribed routes with perhaps speed limits and policing may solve the second, but only ratification of an internationally accepted rule of behaviour will satisfy the third requirement. This paper proposes to develop a set of manœuvres which may be applied as a rule which will be accepted as a possible solution to the third requirement.

In 1260 Brunetto Latini, a native of Florence, was exiled and went to live in France. While there he followed the example of others of his period and compiled a kind of encyclopaedia which he called Li Livres dou Tresor.

In 1802 a young man called Dupré informed the editor of the Monthly Magazine or British Register that Latini had come from France to England as tutor to the son of Richard, Earl of Cornwall, brother of Henry III. While here he had written a series of letters to Guido Cavalcanti, a Florentine poet, describing what he saw in England and that the letters had come into Dupre's possession. During 1802 several free translations from these letters ran through the magazine and no suspicion of their authenticity seems to have been aroused, though when a description of an elephant, said to have been seen in the Tower of London, appeared a correspondent pointed out that it seemed to have been derived from a contemporary Bestiarium.

There is no doubt that the increasing size and speed of aircraft, and in particular the continuing growth in air traffic movements, pose unique problems for the development and use of efficient and safe methods of air navigation and control. The scientific, technological and operational difficulties involved are, of course, quite fundamental. This paper, however, is based on the propositions that such technological opportunities and regulatory systems as may be developed necessarily affect directly or indirectly the use of real resources; and insofar as these resources have a value in alternative uses, they incur costs on the community (as well as prospectively providing benefits). Situations involving economic choice, therefore, necessarily are involved. Air navigation and control systems are not immune from the general objective of achieving an efficient overall distribution of national resources.

“Visual meteorological conditions” (v.m.c.) specifies a forward visibility of at least, say, 5 miles, horizontal distance from cloud of at least, say, 2000 ft., and vertical distance from cloud of at least, say, 500 ft. At any instant, therefore, the airspace may comprise (a) v.m.c. areas (or strictly speaking volumes), and (b) non-v.m.c. areas. The dividing lines (or strictly speaking surfaces) between them may be perceptible or their positions predictable by the aircrew or they may not. If they are neither perceptible nor predictable, then the aircrew cannot possibly ensure that their aircraft does not enter any non-v.m.c. area and it cannot possibly ensure compliance with instructions to ‘maintain v.m.c.’. Whether the aircraft is in a v.m.c. area or in a non-v.m.c. area may be perceptible by the aircrew or it may not. If it is perceptible and if the aircraft immediately reverses direction in a small space, then the aircrew will almost but not quite be able to ‘maintain v.m.c.’. In some cases very small infractions of non-v.m.c. areas may be permissible; in others, not.

With the introduction of larger and faster types of air transport it seems certain that the importance of all-weather take-off and landing for their safe and economic operation will increase during the coming decade. This paper suggests that a vital factor in this development will be the availability to the pilot of up-to-the-minute information on low level visibility and wind conditions applicable to the runway he is to use. The difficulties of obtaining and forecasting these microclimatic factors are discussed.

We now stand at the beginning of a new decade and one which promises to be as progressive and stimulating for civil air transport as any of its predecessors. Great advances were made during the 60's in establishing and steadily improving the performance of sub-sonic jets. Of equal importance was the enormous amount of preparatory work for the introduction of jumbo jets, air buses and supersonic transports during the 70's, and none was more important than the early stages in developing an all-weather landing system. It may be hoped that by the end of this decade a fully operational all-weather landing system will be available for use at all major airports in the world and there is no doubt that progress towards this goal will be vital to the success of the S.S.T.

It seems appropriate first to define and explain the term Area Navigation that lately has almost become a slogan in discussions on short-range radio navigation aids. The term itself does not convey much because virtually any radio navigation system permits navigation in the area of coverage of the associated ground stations; for a systematic classification of navigation systems, the term Area Navigation (herein called ANAV) is unsatisfactory. It can be understood only in the context of air traffic control requirements. For a long while the requirements of short-range navigation systems were almost exclusively governed by the needs of air traffic control systems based on an airways concept. When during recent years A.T.C. methods became less associated with a fixed route structure, especially in the terminal area, the requirements to be met by a navigation system changed accordingly. There now appears to be a general trend for area navigation capability to become available as a substitute for a point-to-point navigation system.

A requirement was stated to Brookes & Gatehouse Ltd. by B.P. Ltd. in 1962 for the measurement of velocity of approach, at the instant of impact against the fenders, of large tankers when berthing at a jetty. This information was required for operational research into the design of jetties for the new super-tankers and for ‘post-mortems’ after heavy impact. Experiments were carried out by us at the Fawley terminal of the Esso Company and the first installation was made by B.P. at their Finnart terminal in January 1963. There has been a continuing demand up to the present time by several oil companies, and a dozen jetties in different parts of the world have now been fitted with this equipment.

Turner has chosen in a recent paper to criticize Moss for inaccurate methods and observes that the inherent inconsistencies are ‘educationally objectionable’. However, he who criticizes must be prepared to be criticized in turn, and when a computer program of the standard evidenced in the printout of PROGRAM 2 is put forward as a general solution to the rhumb-line problem, and one which will enable the navigator to compute his tracks rapidly and accurately, we must needs examine it closely. Such an examination shows that, at the very least, the programmed solution offered is ‘computerizationally objectionable’.

The many references to Omega in your excellent discussions on Navigation and traffic control published in the January issue were particularly gratifying to one who has worked on Omega for the past decade. Especially memorable was Mr. Stringer's statement that ‘[Omega] satisfies the three R's—reliability, redundancy and range’ and Mr. Jones' observation ‘' [Omega] is already the most widely deployed ground-based navigation aid in the world by a very substantial margin’. However, many contributors used words such as ‘somewhat unreliable’ and ‘subject to real problems’ when discussing ambiguity resolution. Perhaps some further remarks on ambiguity resolution are in order.