There have been many new developments in the North Sea during the last seven years since gas was first discovered in the B.P. West Sole field. First, half a dozen other gas-fields have been found and a large quantity of methane has already been piped to Britain. Secondly, oil has been discovered in the northern part of the North Sea between Scotland and Scandinavia. One may well ask why this large source of energy was not discovered many years ago. The reasons are much the same as applied to the gas discovery; the North Sea 10 years ago was not a very good prospect from a geological point of view, and in any case the techniques of exploration and production in offshore areas were not adequate until recently, especially in a place such as the North Sea wher severe storms and tidal streams make operations difficult and hazardous.

This paper falls roughly into three sections: the inter-relationship between economic forces, technological change and occupations, a brief history of navigation in occupational terms, and the present and future state of the occupation. The conclusions drawn may be open to discussion, since it presents a point of view and not a specific piece of research. It is restricted to the occupation of navigation in the Merchant Navy; naval and aircraft navigation appear to be very different as occupations.

Modern digital computers are well known to be extremely fast and accurate, but another attribute which is even more vital in the role of nerve centre to a modern nav./attack system is flexibility. The ground-based computer that carries out a different task every day of the week is now normal, but even in a military aircraft the computer is called upon to fulfil several roles: on the ground analysis and diagnosis, in the air navigation and weapons delivery, and often as flight director computer if the situation demands. Because of its characteristics of carrying out the computations serially in a central processor, a single decision point can alter the whole characteristics of the program; a single switch could make the computer carry out a fault diagnostic program or the navigation/attack program. By the action of one switch the meaning of every other switch and display can be altered. It is this characteristic above all that calls for special displays if full advantage is to be taken of the flexibility in the main computer interface.

AS readers of the Journal will know the Department of Trade and Industry set up in 1971 a Marine Traffic Systems Steering Group, to commission and coordinate research and development relating to the problems of marine traffic behaviour and to consider practical measures which could be undertaken as regards the Dover Strait area. The Group comprises mariners, economists, scientists and administrators from the Department of Trade and Industry including the National Physical Laboratory, representatives of the Civil Aviation Authority, the Ministry of Defence and, more recently, the Chamber of Shipping of the United Kingdom and Trinity House. Hargreaves has recently described briefly some of the earlier work arising out of the Group's existence. This paper describes in more detail the activities of the Steering Group from the time of its first meeting in March 1971 to the present day (October 1973). Many of the results of this activity are already known to Members of the Institute as a result of the publication in the Journal of papers read at the Conference on Marine Traffic Engineering held at the N.P.L. in May 1972 and sponsored jointly by the Royal Institute of Navigation and the Royal Institution of Naval Architects.

Means for position fixing in the North Sea using Decca have expanded greatly over the past 10 years, since the first rig was positioned in 1964, and without precise knowledge of position much of the work observed at sea is valueless. Some offshore problems have therefore changed or have been solved, others remain.

The British Nautical Almanac was first published by Nevil Maskelyne, the Astronomer Royal, in 1766 for the year 1767 and the chief table in it was of lunar distances, which were tabulated at intervals of three hours to the nearest second of arc. On the bicentenary of its publication the theory and practice of lunar distance observation and reduction were reviewed in this Journal.

The objective of this paper is to show that an underwater navigation system can be developed that is technically and economically feasible and of high reliability for long distance under-ice operation. Recent advances in underwater navigation for cruise, exploration and search and rescue operations are considered and applied to the current interest in Arctic waters, where mineral prospecting and oil transportation are potentially important.

The paper was read at a meeting of the Institute held in London on 27 February 1974 with F. A. Haworth in the Chair. Mr. Cestone is from the Naval Ships Systems Command of the United States Department of the Navy; Mr. St. George from the Charles Stark Draper Laboratory of the Massachusetts Institute of Technology.

In this paper the Secretary General of the French Institute of Navigation reviews the progress made in navigation in the Marine Marchande over the last twenty years. The article of course refers specifically to a particular fleet, but it gives a remarkably clear picture of the development of navigation in merchant shipping as a whole, at any rate in the western world. Professor Hugon is an Honorary Member and Gold Medallist of this Institute.

The problems associated with marine traffic engineering in the Baltic area are difficult to solve, and casualty statistics are extremely important as a basis for safety and anti-pollution activities. A statistical analysis has been made of the data relating to a total of 283 ship casualties in 1971–72; the results are presented and the discussion covers local and seasonal distribution, distribution by other time-dependent variables, and weather, visibility and the use of navigation equipment at the time concerned. The statistics further cover the type of ship involved, its nationality, loading condition, age, speed, and the damage arising. This paper was presented at the November meeting of a Navigation Group in Helsinki.

This paper by the Vice-President of the Netherlands Ship Model Basin presents the results of a study performed on the N.S.M.B. ship manœuvring simulator aimed at the development of criteria for the manœuvrability of ships sailing in a current. Six pilots navigated four types of 250,000 d.w.t. tankers in sixteen different conditions of current.

Ships have grown so large that it is no longer taken for granted that they can be manoeuvred as required. The problem can be split up in two aspects, the ship's inherent manoeuvring ability, which is mainly a technical problem, and the mariner's ability to manœuvre the ship, which is mainly a psychological problem.

A basic concept for estimating the probability of collision for a ship navigating through a seaway with congested marine traffic can be derived by applying queuing theory to the relation between collision avoidance manœuvres and the traffic environment. Ships usually perform various ‘services’, such as altering course or collision avoidance, to other ships and geographical obstacles; the analogy of the collision avoidance system to queuing is that each arrival of another ship represents a ‘customer’ and each manœuvre of own ship corresponds to a ‘service’. A model for a collision-avoidance system was constructed analytically from queuing theory and expressed numerically, under assumptions based on traffic surveys and the statistical analysis of collision avoidance procedures at sea, in order to study the feasibilities of the model.

A simple inexpensive optical projection map display is described which converts the range and bearing signals available from ground-based beacon aids such as TACAN or VOR/DME into a continuous map indication of present ground position without additional computing. This provides an area navigation system from such aids within their limits of accuracy, which increases with decreasing range from a beacon.

The display, which is self-synchronous, employs a series of circular map micro-transparencies, each of which is centred on a TACAN or co-located VOR/DME beacon and which can be changed in flight. The transparencies are automatically orientated with reference to beacon magnetic north on insertion, by a notch in the rim. The transparency is rotated by the bearing signal and is translated radially by the range signal to give a continuous indication of present position.

The traffic capacity of a crossing of two fairways is one of the most important problems in marine traffic engineering and a few papers published in Japan deal with this subject, either by theoretical analysis or mathematical simulation. However little is yet known on the size of domain or diameter of evasion, without which any quantitative estimation of capacity is almost impossible. Partly for this purpose a year-long observation was performed in the eastern part of Bisanseto, a strait in the Seto Inland Sea, where the number of crossing encounters is the largest in Japan.

This paper, based on a presidential address given to the British Section, Société des Ingénieurs Civils de France on 11 January 1974, examines the state of sea transport today and proposes a European Maritime Agreement along the lines of the Chicago convention for Civil Air Transport.

The following definitions may be agreed.

Channels all natural or artificial beds of rivers, estuaries or other bodies of water, or a body of water joining two seas, for example the Channel joining the North Sea with the Atlantic Ocean. The word also means ways of access or communications and methods of conveying nonmaterial things, such as in radio and radar systems.

Proper means fit, suitable, efficient and safe; a secondary meaning is correct according to rule and accepted custom.

In this paper the Lucasian Professor of Applied Mathematics in the University of Cambridge studies the role of ocean science in the service of mankind, and examines the interaction between the many disciplines which make up that science. The paper, which was written in May 1972 (and a version of which was published in the Bulletin of the Institute of Mathematics and its Applications for February 1973), was presented at a conference held in Greenwich on 12–14 September 1973 to celebrate the hundredth anniversary of the Royal Naval College. (Note: the National Institute of Oceanography referred to in the text is now known as the Institute of Oceanographic Sciences.)

Keith Best's paper ‘Through the Proper Channels’ was published in the last number of the Journal. The following discussion of its principal proposals took place at an open session of the Technical Committee held in London on 6 May with Captain Maybourn in the Chair. Mr. Best is President of the British Section of the Societé des Ingéneurs Civils de France.

Criticism of the automatic (computerized) plotting systems has so far concentrated on the supposed danger of inadvertent hiding, through immaculate presentation, of the effects of radar, gyro and applied own speed errors, which could lead to false assumptions on the situation being made. However, although not stated in the criticism, the errors in question affect all methods of plotting, so that if the charge is valid it is a challenge to the usefulness of radar plotting as an aid to avoiding collision at sea.

Fujii shows that the collision diameter is about 1/10,000 of the ship length; this figure is to be interpreted as meaning that skilful manœuvres decrease the collision frequency to about 1/10,000 and, since the geometrical collision diameter is of the same order as the ship length L, attention has to be paid to ‘collisions’ which include even slight contact. The probability of a mismanœuvre which leads to stranding is studied using the marine traffic accident ‘library’ of the Japanese Association for Preventing Sea Casualties and the Report on the Marine Traffic Survey of the same Association. The library includes records of casualties in the original cards both of Marine Casualty Statistics and Statistics of Marine Accidents Requiring Rescue. The authors were members of the working group which prepared both the library and the Report. In this paper stranding includes any kind of grounding unless intentional, e.g. after collision or fire, and includes groundings with slight damage such as bottom contact.

This paper discusses navigation tables based on the decomposition of the astronomical triangle into two right-angled spherical triangles by a great circle arc extending from the zenith to the meridian of an observed celestial body. In a recent fairly comprehensive study of some thirty short-method tables in which the division of the PZX-triangle forms the principle of construction, nineteen are of the species to be discussed.

Following the introduction in 1871 of the first short-method table by Thomson, some twenty years were to pass before any real advance was made in this field. Thomson's table was in fact re-issued by Kortazzi in 1880 and by Collet in 1891, in modified forms, but it was Professor F. Souillagouët of France who is to be credited for introducing something novel and decidedly better than Thomson's table. Unlike the earlier ones it was designed specifically for the Marcq Saint Hilaire method of sight reduction and, in contrast to Thomson's table which was based on the division of the PZX-triangle by a perpendicular from X, Souillagouët's was based on division by a perpendicular from Z.

This paper surveys the present methods of pilotage and berthing, discusses some of the statistics of collision and grounding in confined waters, and suggests the development of shipborne automatic control devices to be used for the pilotage and berthing of large vessels. The proposed system, with its associated shore-based equipment, would carry out a similar function to the automatic landing devices fitted in aircraft, and would be part of an overall marine traffic control system. This system would enable large ships to be berthed automatically in reduced visibility and improve the safety of the movement of large ships in congested waters. The author lectures in the Department of Marine Electronics at Southampton College of Technology.