Last year this Journal contained two articles by the writer in which he suggested the potential of fully automated radar plotting systems (FARP) in aiding collision avoidance. This was done by considering a number of past collisions and showing how different the behaviour of the ships involved might have been had they been using FARPs. This was an operational study and not a statistical analysis. He followed the line taken in previous articles starting as far back as 1965 and continuing in 1970 with some details of earlier automatic plotters and in 1972 with a comparison of manual and automatic plotting capabilities. In 1974 and 1975 there was a comparison of the different philosophies embodied in the later FARPs leading up to the studies of past collisions in 1977.

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.

The term marine pilot is applied to the man with local knowledge who acts as a guide to mariners in his own specific and limited district, but it is difficult to confine the work of a pilot to anything so specific. Over eight centuries Cinque Ports' pilots have conducted snipping from the Dungeness-Dover sector of the English Channel both into the Cinque Ports and into the ports of the Thames. They have also taken ships to the more northerly waters of the British Isles and were often asked to pilot ships along the European coast as far as the Baltic. They do this today and for the purposes of this paper they are pilots who work in a defined district but who are not necessarily confined to that district.

Prior to the introduction of three Ocean Surveying Ships in the years 1965–66, the Hydrographer's surveys were generally concerned with the recording of depth against a geographical position obtained from manually reading and plotting sextant angles, radar ranges or, more recently, electronic navigational aid data. The new ships were however the first Royal Naval ships to be designed with combined oceanographic, geophysical and hydrographic roles and to have no supplementary naval function. They contained instruments for measuring the Earth's gravitational and magnetic fields as well as depth; as a consequence the number of men required to read, record and plot this data increased. With the use of an electronic positioning system to provide the horizontal control for the surveys it became possible to carry out surveys throughout the full 24 hours each day.

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.

For the past few years it has been technically possible to produce digital versions of charts and maps but the manual digitizing of very large amounts of irregular line and point data is both slow and prone to error; the benefits of automation in this field are less clear-cut than in the production of computed linework such as borders and lattices. Semi-automatic line digitizing equipment is just coming on to the market and this will undoubtedly speed up data acquisition rates, particularly where good-quality line work is being digitized. Nevertheless some mapping authorities (e.g. the United Kingdom Ordnance Survey) have already made considerable progress in the digitizing of maps, both to provide input for the automated fair-drawing of these maps on one or more scales and to supply digital versions of selected features (e.g. road and boundary patterns, frontings of buildings) to prospective customers, such as the public utility group—gas, electricity, telephone and drainage authorities.

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.

The introduction of digital computers in hydrographic surveying has led to a decrease in routine work and an increase in time for decision making. In merchant ships there are likely to be similar benefits, but there are many facets to the introduction of digital computers. The main criterion, if the introduction is to be a success, must be a considerable improvement in the performance of men and equipment when compared with the additional cost of a revised system, including training in its use. There are two main decision-making phases in navigation—voyage planning and watchkeeping; we must therefore consider the assistance that electronic data processing could give to the navigator in providing data on which plans can be evaluated, progress monitored and decisions made.

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.

Decca have undertaken a study for the Department of Industry of possible integrated navigation systems for use in merchant ships, particularly VLCCs, and also the development and supply of an advanced navigation information system for offshore patrol vessels which uses many of the techniques proposed in the earlier civil study. This computer system provides for the integration of various data sources including radar, the processing of the data and display; a prominent item is the Admiralty chart.

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.

At an open meeting of the Technical Committee held in London on 26 April 1978, with Dr. J. F. KEMP in the Chair, the broad question was discussed of the relative benefits of carrying navigational devices in an aircraft as against installing them on the ground. Introducing the discussion Captain B. J. CALVERT of British Airways suggested that for landing in very poor visibility there was no either-or choice; any system must be cooperative and involve the combination of air and ground components. The question was where to strike the balance. With the redevelopment of a fog-dispersal device (for one was used in World War II) it seemed possible to re-examine the question. The fact that there were now many years of airline experience of low visibility landings made the discussion even more appropriate.