Over the past thirty years progress in the technologies associated with navigation has been so rapid as to produce a change in the balance between the art of the navigator and the practice of the technologist. The Royal Institute of Navigation was founded at the beginning of this era and one of its major aims was to provide a forum for discussions between practising navigators, scientists and engineers. Therefore, it seems that a consideration of the technical changes should help the Institute to adapt, much as all our social institutions are adapting, as a result of wider changes brought about by science and technology.

The following paper was presented at a meeting of the Institute held in London on 21 February 1979 with the President, Captain R. Maybourn, in the Chair. It considers some of the factors which apply in the context of overall safety and the weightings which they should be assigned in estimating the optimal speed for ships in given circumstances and conditions.

In air traffic control the speed of individual aircraft cannot be significantly varied without unacceptable economic penalties, or the aircraft falling out of the sky. In the case of ships the speed is a useful variable for traffic management and individual ships can choose, or be assigned, any value between zero and their normal service speed. The following discussion concerns the choice of a suitable speed for marine traffic in terms of safety criteria.

There have been two distinct phases in the development of radio aids to navigation. The first, which must be regarded as the true pioneer period, followed rapidly upon the development of wireless telegraphy by Marconi and others; it was soon realized that the early aerials employed had directional properties and that this phenomenon could be used to obtain a bearing.

In 1947 Dr G. M. Clemence, then Director of the Nautical Almanac Office at the US Naval Observatory, and I visited a number of US institutions engaged in the development of digital computing machines, with a view to their application to the calculation of astronomical ephemerides. We were, at that time, planning the revision of the almanacs for surface navigation which led, in due course, to the unification of The American Nautical Almanac and The Nautical Almanac, Abridged for the Use of Seamen in essentially its present form as (from 1960 onwards) The Nautical Almanac. We were told (actually by an astronomer, Dr T. E. Sterne) that our efforts were pointless since, in the near future, a navigator would be able to calculate the astronomical data that he required to reduce his observations by digital computer; conventional almanacs would no longer be needed. Thirty years later that optimistic forecast, although not yet realized, requires consideration. However, no one could have foreseen that the microprocessor of today is far more powerful than the most elaborate computer that was then practically visualized. For that matter, few would have thought that there would still have been a demand for astronomical data for navigation; the basic principles of many other aids to navigation were rapidly being developed.

Presented at a meeting of the Solent Branch of the Institute held, by courtesy of the Director, at the College of Nautical Studies, Warsash, on 21 September 1978.

Put your trust in God and the Admiralty Chart! Every one of nearly four million charts issued each year by the Hydrographic Department is as up to date as possible on the day on which it leaves our premises; nevertheless we are increasingly conscious that far too many of the charts are no longer adequate for the uses to which they are now being put.

The purpose of this paper, which was presented at the seminar on Coastal Navigation described on p. 448, is to consider the role of ‘dead reckoning’ at the present time, in the context of coastal navigation, and to indicate one or two devices which might alleviate the navigator's task in trying conditions and perhaps improve the accuracy of the result.

When planning the replacement of an existing shore-based radar advice chain, which may have admirably served the port area under consideration for the past fifteen or twenty years, a number of basic elements have to be reviewed. The review and the ensuing process of analysis should be steps towards the adoption of a basic philosophy for the eventual development of a replacement system; this is necessary to judge requirements in relation to the many possible solutions, ranging from a simple shore-based radar advice service to sophisticated vessel traffic management systems. Elements for consideration include:

(i) The area to be served, present and future.

(ii) The traffic pattern, present and future.

(iii) The technology available or under development.

(iv) The other operational and administrative services available to shipping.

(v) The quality of manning and manning scales.

(vi) The economics of the shipping industry.

(vii) The cost of the new system.

(viii) The distribution of this cost over shipping and the community in general.

(ix) Legal aspects.

Besides these factual considerations and their analysis we should develop a philosophy regarding the aims of the system, which could be an improvement in port operation efficiency, in traffic safety, or in vessel turn-around time. The realization of these aims will probably result in economic benefits both for the port and for shipping and these will have to be weighed when investigating the distribution of system cost over shipping and the community in general.

Numerous collisions over the years have emphasized the need for rapid and efficient ship-to-ship voice communication systems. Such systems, set up to satisfy the demand for more and better channels through which messages can be sent, should guarantee that both sender and receiver come to share the same thoughts and feelings. ‘It can be said that two expressions have the same meaning if their utterance results in the same change of behaviour.’ Recognizing that voice communication systems cannot be effective until all parties speak and understand the same ‘language’, the Maritime Safety Committee of IMCO has developed the Standard Marine Navigational Vocabulary, a significant landmark in the attempt to achieve the maximum safety to navigation and the most appropriate conduct of ships at sea. This paper will concentrate on the objectives of the Vocabulary and will try to ascertain if such objectives have been achieved. The analysis will emphasize the viewpoint of ‘non-English speaking people’ using English ‘for the interchange of intelligence between individuals of all maritime nations’, and will take linguistic considerations into account.

In this paper, which was presented at the seminar on Coastal Navigation referred to on p. 448, the author describes a new system of radio navigation particularly suited to small craft and coastal vessels.

This paper reviews the objectives of a new radio aid termed the Radio Lighthouse and describes its scope and use. The results achieved to date are given, as well as plans for the immediate future. A consideration of the options available in implementing the system and methods of obtaining navigational data from the system conclude the paper.

In recent years a great deal of research has been carried out in the twin fields of ship and aircraft navigational systems. The areas investigated have been closely related, but since 1945 the work has always been conducted independently, with virtually no cross-reference between the two industries. During the war years, however, this was not so and intensive research at that time resulted in some remarkable technical advances which related to both fields. The aids to navigation which then emerged have remained until recently absolutely fundamental and in marine navigation they have formed a platform of reliability, particularly the Decca Navigator system and radar. In aviation, airline competition on the transatlantic routes and the need for absolute safety has maintained a continuing process of evolution in the design of navigation and control systems. One such aid to emerge has been DME and, with the research and development complete, this is now a standard device for both military and civil operators throughout the world. A chain of ground beacons has been set up to cover the major world air routes and there are a considerable number of these beacons in the United Kingdom.

Depending on how the encounter rate is defined, different values can be found for the crossing angle or speed giving the smallest encounter rate. When dealing with ‘optimum crossing angles’ or ‘optimum speeds’ it is therefore proper to know which definition is taken as a basis, i.e. which expression is minimized.

The paper by Captain Burger and Captain Corbet was presented by Captain Corbet at a meeting of the Arab Institute of Navigation held in Alexandria on 9 April 1979. Before the meeting M. W. Richey, as Director of the Royal Institute of Navigation, gave a short talk to the Arab Institute.

On the 9 August 1974 the steam tanker Metula grounded in the First Narrows of the Magellan Strait. The grounding of this deeply laden VLCC provoked very little publicity either on television or in the press, probably because of the remoteness of the area. The Metula was a first-class, well-found vessel manned by properly qualified and experienced personnel, and had two Chilean pilots on board to assist with the navigation through the Strait. How could such an accident happen?

D. H. Sadler writes: I am indebted to Mr Luis de Sobrino of 1976 West 14th Avenue, Vancouver BC, Canada, for pointing out the need for the following correction to my paper ‘Lunar methods for longitude without time’ (Journal, 31, 245, lines 16, 17). The altitude corrections CM and CS should include corrections only for parallax and refraction; the word ‘semi-diameter’ should be omitted.

In this paper Dr Y. Iijima of the Tokyo University of Mercantile Marine and Professor K. Honda of the Kobe University of Mercantile Marine examine the hydrodynamic and navigational factors that determine the safe width of a channel for vessels of a given size and performance characteristics. The results are compared with the widths of existing channels in Japan and elsewhere.

There has recently been some discussion on the suspected ‘sailing effect’ experienced by ships lying immobilized in a seaway. It was suspected that drift direction may not be truly down-wind, and that on VLCCs in the ballasted condition the sailing effect could be magnified. Few practical data were however available and could easily be spoiled by the effects of current, or become unreliable if established under the influence of light to moderate winds.

An unusual set of circumstances combined on the 3 August 1977 when I was Chief Officer of the Shell tanker SS Lima on her maiden voyage to the Persian Gulf. As can happen early in a ship's life, trouble developed in the engine room requiring the boiler to be shut down for about two days. The first signs of the problem were discovered a few days earlier but the stoppage was planned so that the ship would have plenty of sea room when undergoing repairs. A position off Maputo was chosen, and when within the selected area the ship was stopped and the repairs carried out. During this period the ship was allowed to drift freely and as usual daily positions were obtained at morning and evening twilight and at noon. Figure 1 is an outline chart of the area showing the observed positions. For these times the ship's head is also given, in addition to the associated wind direction and speed.

The Global Positioning System, Navstar, is an advanced satellite-based navigation system which is currently under development and evaluation in the United States of America. Progress has been very fully reported in the open literature and a definitive paper on the concept has in fact been published in this Journal. The concept has now been experimentally validated and much of the evidence which supports this validation has in turn been published.

The impact of Navstar on navigation in the period beyond 1985 is potentially very great indeed in that it offers, worldwide, a navigation capability to surface and aerospace users of a standard of accuracy combined with continuous availability which is currently associated only with short-range aids.

This paper has the objective of presenting (a) a general introduction to the physical principles on which Navstar is based, followed by (b) a survey of its potential relevance to the operational needs of various classes of user. Finally there is some more speculative matter in the form of (c) a discussion of the potential impact of successful implementation of Navstar on current and projected future navigation systems.

The Amoco Cadiz and the Work of the Institute. Seaborne trade calls for international agreement but it is not a matter that attracts much public attention. That is why, as Beattie has pointed out very clearly in his paper ‘Traffic Routing at Sea 1957–1977’ presented to the Institute on 14 December 1977, all the major steps taken to bring some order into the regulation of maritime traffic have been due to the initiative of mariners or maritime organizations. International action was only taken later, to give a legal sanction to such proposals as were felt to be necessary. In any case there was no international authority until 1958 when IMCO (the Inter-governmental Maritime Consultative Organization) took over the direction of maritime affairs between the International Safety of Life at Sea Conferences, and these were not convened at regular intervals. One can easily see that under these conditions progress was slow, depending as it did on either the initiative of seafaring people or on some turn of events that demanded a new approach.

Modern ship control and navigation systems involve a complex variety of intricately interwoven electronic, electrical, mechanical and hydraulic devices. It has become appropriate therefore to devise a convenient method for representing mathematically the dynamic characteristics of these systems and the elements which comprise them, so that block-diagram modelling can be implemented. This is ideal for displaying the interrelationships of such systems pictorially and has the added advantage of simplicity and of indicating realistically the actual processes which are taking place, as the models refer to the relationship between mathematics and the real world.

In Virginia's splendid State House at Richmond there stands a marble bust of Matthew Fontaine Maury, one of Virginia's more eminent natural scientists. It might be a matter for dismay for a mariner to read the inscription below the elegant bust, to the effect that this remarkable man owed his fame to having invented an electric torpedo; Maury's fame stands on a much firmer foundation than this! In 1916 the State Board of Education of Virginia set January 14th as ‘Maury Day’ in honour of its celebrated son, and each year on that day Virginian schoolchildren observe and commemorate his birthday. Because of his service to navigation Matthew Fontaine Maury merits the title ‘Pathfinder of the Seas’.

Separation standards are used for assuring the safe and effective operation of aircraft in a traffic control environment and as aircraft operations increase in number the need to reconsider separation standards is strongly voiced both by operators and controllers. A panel, the Review of the General Concept of Separation Panel (RGCSP), has been organized by ICAO and the possibility of reducing conventional separation standards has been discussed. Mathematical models for estimating collision risk due to loss of separation between aircraft require data on navigation accuracy. In general, three-dimensional radars are used for height finding but these are complicated and expensive.

The altitude of the cruising aircraft is required within about 100 ft. In the simplified radar here described a rotating antenna produces a fan beam for scanning aircraft flying overhead. The data obtained from several scans are processed by a mini-computer and the height of the aircraft estimated by a least-square method and sequential approximation. Between the items of information obtained for each scan (the distance, the elevation angle and the data acquisition time) a theoretical relationship is established as an observation equation, one of the coefficients of which includes the height information. The coefficient is determined by a curve-fitting method. The paper first describes the method of analysis for height estimation and then an evaluation of the accuracy of the method by a computer simulation.