In October this year an international conference on the revision of the International Regulations for Preventing Collisions at Sea will be held in London. A working party appointed by the Maritime Safety Committee of Imco, under the chairmanship of Captain A. C. Manson of the Department of Trade and Industry, has drawn up proposals for the revision of the present regulations. Captain Manson described these proposals to an open session of the Technical Committee held in London on 17 May 1972 with Captain D. A. G. Dickens, an Elder Brother of Trinity House, in the Chair. Introducing the subject the Chairman said that the Institute, through its Journal, the discussions it had promoted on previous occasions, and through the working party set up in 1970, had taken a significant part in forming opinion on the issues involved. In particular perhaps it had ventilated the suggestions that collision avoidance might better be based on positive manœuvring instructions rather than by simply apportioning responsibility. The long-term influence of these suggestions may well be considerable even though they might not in the event be reflected in the Rules now being proposed.

At the tripartite conference held in Eastbourne in May 1964 by this Institute, the French Institute of Navigation and the Deutsche Gesellshaft fur Ortung und Navigation, it was agreed to set up a representative working group to study the environment and its influence on the navigation systems to be chosen for supersonic transport aircraft, and to clarify the governing parameters. The early work of the group was necessarily hampered and delayed by a lack of reliable data on the probable performance of S.S.T. aircraft and on their manoeuvring capabilities and limitations. Flight trials with Concorde may suggest some modification of figures given in this paper.

The group has now completed its work and a report will be published by the Deutsche Gesellshaft für Ortung und Navigation. In addition to the two sections on meteorological factors and air traffic control, which appear to be of more general interest to readers and are included in an abridged form in this issue of the Journal, the complete report also covers the probable performance characteristics of S.S.T. aircraft and a review of available navigation systems. The temperature frequencies discussed in section 4 are illustrated in a paper by Wehry published in July 1968 (Journal, 21, 277) and will be reproduced in the final report. The Chairman of the group was Dr. Karl Karwath.

Two of the proposed airborne collision-avoidance devices at present under discussion are the A.T.A. time-frequency system and a later proposal termed SECANT. The present paper attempts to discuss the geometry of the escape manœuvres associated with the use of one or other of these devices; the electronic problems involved in these ingenious but intricate devices will here be largely ignored, and discussion will be confined to the problems facing two conventional aircraft in an encounter at an appreciable altitude.

Many may consider it presumptuous of the guinea-pig to voice an opinion on the experiment to which he is to be subjected. I hope this is not so, because I view the shipowner not as the guinea-pig but as the prospective customer for any advances which are made in marine traffic engineering technology. The shipowners of the world are undoubtedly going to pay directly or indirectly for any traffic regulation schemes which are set up. It is certainly not part of my theme that the customer is always right—he may not know what he wants until he has been subjected to a promotional advertising campaign and he may be excessively gullible in swallowing such propaganda—but there is possibly value in the customer saying what he thinks he wants and airing doubts he may have before he is subjected to these pressures. I therefore welcome the opportunity to give a shipowner's view on traffic regulation.

Enunciating the doctrine of the freedom of the high seas, Queen Elizabeth said ‘… the use of the sea is common to all, neither may any title to the ocean belong to any people or private man…’. It might have been more appropriately phrased if she had said—the sea is a free-forall, because until comparatively recently the common interpretation of the freedom of the sea has been the right for all to sail as and how they please, unhindered and unrestricted except for some internationally agreed rules for preventing collision and the demands of prudent seamanship to avoid stranding. Indeed masters and owners alike considered it their unquestioned right to use the waters of their choice and, in close quarter situations, it was often the man with the strongest nerves who won the day.

In this age of explosive expansion in nearly every aspect of human endeavour our ability to make accurate forecasts is becoming increasingly important. We cannot wait until we run out of oil to find a new source of energy. We cannot wait until we can't stand living on the earth to slow down the rate of pollution. We cannot wait until there is no room left to stand on dry land before we do something about birth rate. We must predict what is likely to happen as a result of trends and then find ways either to change the trends or protect ourselves from the consequences.

The committee which looked into the scientific and technological aspects of the Torrey Canyon disaster in 1967 recommended that an assessment should be made of the probable future frequency of large-scale oil pollution along the United Kingdom coastline so that the scale of effort necessary to meet such threats could be determined. The Defence Operational Analysis Establishment of the Ministry of Defence, which has considerable experience in the collection and analysis of large amounts of data, was considered best suited to undertake such an assignment.

In this paper a study is made of that area of marine traffic engineering which is concerned with collision avoidance, and within that area the sub-section in which human factors are involved.

Collision avoidance at sea is mainly achieved by adherence to the rules for preventing collisions, by routing schemes for separating traffic in high density areas and, within certain port limits, by local rules and advisory services, or occasionally by direct control of ship movements. To these well defined factors may be added the mariner's accumulated experience and instinct for self-preservation which gives rise to such nebulous, but not negligible, entities as the ‘seaman's eye’ and the ‘navigator's sixth sense’.

A draft of this paper was circulated for the open meeting of the Technical Committee on 17 May 1972, when the forthcoming revision of the Collision Regulations by Imco was discussed (see page 427).

Radar has been in general use in merchant ships since the end of the Second World War and during this time the Regulations for the Prevention of Collision at sea have undergone two amendments at International Safety Conferences, in 1948 and 1960. The amended regulations were ratified and brought into use in 1954 and 1965 respectively. The 1948 regulations made no reference to the use of radar whatsoever—radar for commercial use was still in its infancy in 1948 and indeed little was then known about its capabilities and limitations, nor of the operational difficulties it was going to present even before these 1948 regulations were finally ratified in 1954.

John Hadley (1670–1744), Vice-President of the Royal Society of London, communicated his ‘Description of a new Instrument for taking Angles’ to the Society on 13 May 1731. Hadley's invention for the first time provided the navigator with an instrument by which he could measure altitudes of celestial bodies with ease and accuracy on board a lively ship at sea. It was not however until about 1750, when the instrument was to be found on board vessels of the East India Company, that Hadley's quadrant (or octant as it is sometimes called) rapidly came into general use.

The controversy over the introduction of corrections to standard time, so as to force agreement between Atomic Time and Mean Solar Time seems to have its roots in an erroneous concept of the meaning or concept of the entity we call Time. For example, the preamble to H. M. Smith's paper on ‘Time Data and Navigation’ suggests that ‘…Greenwich Time and longitude are inseparable…’ and in D. H. Sadler's paper on U.T.C. there is an odd confusion in noting that Time is a measure of the rotation of the Earth on its axis and at the same time that the rotation is not uniform.