In his Presidential Address, presented at the Annual General Meeting of the Institute held in London on 19 October 1977, Sir Edward Fennessy, until recently Managing Director Telecommunications at the Post Office, traces the role of navigation in the development of ocean cable laying from the earliest days. Today, telephone cables capable of bearing several thousand telephone conversations link the continents; plans are now well advanced for the laying of a cable between Cornwall and the United States which will provide some four thousand circuits. To lay and maintain these cables calls for all the precision obtainable from the most modern electronic aids to navigation and position fixing, including the satellites.

The Home Office in January 1977 invited submissions for inclusion in the United Kingdom proposals to the World Administrative Radio Conference 1979 (WARC 1979.) Prior to that, in August 1976 in Boston, U.S.A., the member Institutes of the International Association of Institutes of Navigation had agreed to exchange views on matters of concern to the world's navigational community which in particular might be considered by WARC. It was envisaged that any approach by the various national Institutes would be through their own administrations.

The reckoning of a ship is the up-to-date record of the courses and distances made through the water since the ship's position was last fixed by observation. The importance of keeping a careful reckoning was paramount in circumstances when observational methods of fixing were not available. In the early days of sea voyaging, even before astronomical methods for checking position had become available, the mariner who would know his ship's position (essentially to estimate his arrival time at his destination) was forced to rely on his reckoning—no other way was at hand when out of sight of land.

Mr. Collins, Senior Scientific Officer at A & AEE, describes the testing of a modern strike aircraft navigation system. A brief description of such systems together with an outline of a typical flight profile leads to a discussion of the problems of evaluation and the techniques adopted. The paper was read by Mr. T. O. Coldwell, also of A & AEE, at a meeting of the Institute in London on 18 May 1977 with the President in the Chair.

The author of this paper, which was presented at a meeting of the Institute in London on 16 March 1977 with Captain B. J. Calvert in the Chafr, is the President of Jeppesen Sanderson Inc. He traces the history of the Jeppesen Company's charts from their early beginnings when map reading and dead reckoning were the only aids to air navigation to their adaptation to modern automated airborne systems.

Aerial photography has revolutionized the art of map making over land and if the depth of water could be measured from an aircraft a similar revolution might be expected in hydrography. In 1971 an airborne laser land profiler, designed and constructed at the Weapons Research Establishment, Adelaide, was put into service. At the suggestion of Captain J. H. S. Osborn, then the Hydrographer, R.A.N., this was modified to profile the sea bed and flight tested in June 1975. It was found that, in the vicinity of Adelaide, reflections from the sea bed could be obtained down to 30 m and in places down to 40 m. With an airborne device it becomes possible to survey an area instead of a line and work since has been concentrated on developing a system which will scan at right angles to the aircraft's track.

Rule 10 of the new Collision Regulations deals with the conduct of vessels in Imco adopted traffic separation schemes. In this paper, which was presented at a meeting of the Institute in London on 20 April 1977 with Commander R. B. Richardson, R.N. (ret.) in the Chair, Commander Paton, Hydrographic Adviser to the Department of Trade, discusses the traffic situation in the English Channel and Southern North Sea in the light of this Rule with particular emphasis on encounter situations at route junctions and the problems of crossing traffic.

When radar was first introduced to the merchant fleets of the world, many people felt that a practical solution to the collision avoidance problem had been found. However, a review of worldwide collision statistics of the past 20 years indicates that, in spite of the expanded use of radar, the over-all collision rate remains alarmingly high. Because of radar's less than perfect record for preventing ship collisions, development of various types of collision avoidance systems has taken place. The implied promise in this development is that the computer-aided radar will provide a lasting answer to the collision avoidance problem.

The Royal Navy employs naval architects to design its ships and a number of establishments exist to advise the Director General, Ships, on various specialist subjects connected with warship design. The Admiralty Experiment Works at Haslar, near Gosport, (AEW) which was founded in 1872 by the father of modern naval architecture hydrodynamics, William Froude, advises the Director General on all aspects connected with hydrodynamics. Froude's activities and those of his son R. E. Froude, who succeeded him as Superintendent, covered a wide field but the study of resistance and propulsion in calm water occupied most of their energies. William Froude was indeed responsible for the first real understanding of the mechanism of ship resistance and was able to demonstrate that the resistance of a ship could be accurately predicted from model experiment results.

A model is developed for conflicts between ships at route intersections. Quantitative measures are presented for conflict intensity and duration and for intersection capacity. These measures are shown to be related to the geometry of the intersection and to the statistics of the incident flows. An optimum intersection angle is found.

Studies have already been published on the probability of collision at sea, the effect of darkness and reduced visibility on the probability of collision, and on the distribution of collisions in particular areas. Only Minorsky and Comstock appear to have studied the extent of the resulting damage and sufficient data are not available for detailed analysis.

The establishment and operation of any traffic management system calls for a considerable outlay, so that an objective estimate of the extent of collision losses is often required. Such a cost/benefit survey was carried out by the Japan Transport Economics Research Centre on the assumption that a traffic management system can greatly reduce the incidence of collisions involving vessels of over 3000 g.r.t. Since half the aggregate loss is shown to relate to these large vessels (and considering their increasing capital value), an expenditure of ten billion yen or more (£20 million) over a period of ten years would appear to be cost effective if its primary purpose were to avert accidents to large vessels.

When manœuvring ships, mariners usually pay a great deal of attention to the rate at which the heading changes but the direction in which the ship actually moves may differ from the direction in which she is heading. This difference may be caused not only by current but also by the ship's drift velocity through the water in a direction perpendicular to the heading. This velocity is hard to recognize but can cause a turning moment on the ship, whether this is desired or not. In difficult manœuvres which cannot always be accomplished by changes of heading only, one can use the effects of this drift velocity. The drift angle, the angle between the heading and the direction in which the centre of gravity moves through the water, must not be confused with the course allowance necessary to make good a track over the ground when there is a current.

An ever increasing traffic density and the larger dimensions and higher speeds of modern ships all make the task of navigating and manœuvring a vessel more difficult. To make the task easier more emphasis has been placed on the human engineering aspects in the design of navigation bridges and on automation. Increasing automation has changed the man-machine relationship, in particular man is relegated more and more to a monitoring role; predictions about the ultimate of automation, the unmanned ship, have not yet come to pass but the increasing importance of the bridge as a result of automation is certainly recognized. However, to understand the process of steering not only must the layout of the navigation bridge be studied but also the visual impression of the external environment. It is obviously important to adapt the conditions of the working environment to human aptitudes, for this is the only way to enable man to correct and control the system in complex situations. But such an approach demands a general knowledge concerning human aptitudes and it is necessary to study a man's behaviour in varied situations to discover his inherent limitations.

When vessels are involved in collision it is usually a result of failure to comply with the Collision Regulations or breach of the duty to exercise good seamanship. If both vessels are to blame they will in most countries be liable for the damage in proportion to their degrees of blame. A vessel claiming compensation for loss and damages will normally have the burden of proving that the other vessel has been negligent, in navigation or otherwise, and to fulfil that obligation the events leading up to the collision must be established as far as possible. For that purpose witnesses are examined and log books and other records on board are studied, although very often the facts are found to be in dispute between the parties involved. The reason may be that the statements of the witnesses are contradictory and impossible to reconcile, even if due allowance is given to the difficulties in making accurate estimates of time, distances, bearings, speed and course alterations. A closer examination of the observations made and the manœuvres carried out is therefore required.

The 1972 Collision Regulations, which came into force in July 1977, strengthen the injunction on all vessels to keep a proper lookout by making it the subject of a separate Rule rather than including it in a general statement relating to the ordinary practice of seamen. The old Rule which laid down that nothing in the Rules would exonerate any vessel from the consequences of (amongst other things) ‘any neglect to keep a proper lookout’ virtually left what constitutes a proper lookout to the Courts. Rule 5 of the 1972 Regulations is much more specific. It reads: ‘Every vessel shall at all times maintain a proper lookout by sight and hearing as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and the risk of collision’. The Regulations apply in effect to ‘every description of water craft’ although it is reasonable to suppose from their source that the kind of vessel most in mind, unless otherwise stated, is the power-driven ship rather than, say, sampans or dugout canoes.

Through the mediacy of Professor Torao Mozai and the courtesy of Captain T. Iimura of Omron Tateisi Electronics, Tokyo, I was lent a prototype Omron lop NC Astro-navigation computer to evaluate during the course of a singlehanded race in Jester from Newport, Rhode Island, to Bermuda and the subsequent voyage back to England. Although it has been developed as an all-purpose navigation computer, the particular requirements of single-handed oceanic navigation might, it was thought, provide a useful commentary on this kind of instrument; and the environment of a small boat, so close to the sea surface and inevitably inimical to electronic equipment, would be an austere test of the instrument's seaworthiness.

This note is intended for navigators and so far as possible computer terms will be avoided. (The instrument is named a computer by its makers and will be referred to as such, rather than as a calculator, throughout.) The computer weighs 2·5 kg. and measures 200 × 289 × 91 mm. It operates from either the mains or batteries, and can be used for 10 hours continuously without a battery recharge.

With reference to Captain Emden's paper in the April 1975 issue of this Journal, in which he refers to the control and identification of shipping passing through the English Channel, and the numerous articles by Captain Wylie on the subject of computerized shipborne collision avoidance systems, why not adapt the ship-borne radar systems for land based control of Channel traffic ? A modified shore based system would, with present and predicted traffic movement, be ideally suited to this type of application. As to the problem of operator traffic identification and control, the present civil air traffic control procedures would seem to provide the ideal solution; if all shipping were required to carry dual channel multi-code transponders in addition to the current obligatory navaids.