Whatever the word ‘navigation’ is taken to mean, it must, etymologically, be something one does to a ship. What a pity that the name ‘airship’ was given so early in the evolution of aviation to its dinosaurs! The modern airliner is truly a ship of the air. There was a move, half a century ago, to coin the word ‘avigation’ but, apart from the obvious retort that, if ‘navigation’ is of ships, ‘avigation’ is strictly for the birds, the term ‘air navigation’ had already been established by the International Convention on Air Navigation and the Air Navigation Acts by which Parliament legislates on aviation in general and its commercial application in particular.

1. ENVIRONMENTAL FACTORS. Since 1975 the inadequacy of knowledge of the depth and shape of the seabed on the continental shelves has become increasingly apparent, as navigational safety has been pushed to further limits in response to economic factors. Less than half of the British continental shelf, defined approximately by the 200 m depth contour, has been surveyed by echo-sounder and only a small proportion to full modern standards. There are inevitably many natural hazards still to be discovered. Inadequate knowledge can have particularly serious effects in heavily trafficked shallow areas, where patches of the seabed may show instability in the form of mobile sandwaves. Seabed wrecks and obstructions, some of them wartime relics, are another problem; thanks to the use of modern sidescan sonar, in 10 years the number of wrecks in the UK area databank has risen from 14000 to 22000.

1. INTRODUCTION. Interest in the use of video displays for nautical chart presentation has increased rapidly during the last two years. Eaton et al. at the Second International Hydrographic Technical Conference provided a list of ten different systems already in production. Oshima speaking at a Workshop on the subject in Canada, early in 1985, mentioned that some 4000 Japanese fishing boats and 150 merchant vessels now carry electronic charts of varying degrees of complexity.

1. INTRODUCTION. The Collision Regulations are designed to assist navigators to avoid collisions at sea. However, because of their qualitative nature it has been proposed that the Regulations should be supplemented by quantitative references to give practical meaning to concepts like ‘safe’ passing distance, ‘early’ action, etc. (Cockcroft and Lameijer, 1982). The problem of interpretation and quantification of the Regulations has been analysed in a recent paper by Wu (1984), considering in particular the concepts of ‘substantial’ action to avoid a collision, and the distance of ‘last-minute’ action in turning to avoid a collision. These analyses, along with many others, are concerned with developing prescriptive guidelines for mariners, in accordance with the Regulations.

In this paper the role of the helmsman in terms of man–machine systems theory, such as is frequently used in aerospace work is considered and the literature of the subject surveyed in so far as it relates to the control of seagoing vessels. Lieutenant-Commander Sutton is in the Control Engineering Department at the Royal Naval Engineering College, Plymouth, and Professor Towill is head of the Department of Mechanical Engineering at UWIST, Cardiff.

1. INTRODUCTION. The controlled deceleration of a ship in the final approaches to the berthing area is of crucial importance to ensure that the ship is stopped in time and can be manoeuvred to the berth by assistant tugs. Shipborne instrumentation cannot be relied upon entirely to assist the ship handler in this aspect because, with very few exceptions, it does not give sufficiently accurate information at very low speeds and minimum underkeel clearances. Traditionally of course, it is part of the ship handler's skill to judge the ship speed and deceleration by eye and it is important that this skill is finely developed to arrive correctly at the manoeuvring area. It is however the case that the judgment of very low speeds becomes increasingly difficult with the larger ships, yet it is with such ships that this judgment is the most critical.

An application of the model to manoeuvre ships based on the range to domain over range rate (RDRR) concept is described. A simulation of a training simulator has been set up on which the target ships manoeuvre by the RDRR model in response to mariner controlled ships. Results of experiments show that the RDRR model manoeuvres targets realistically. The applications are reduced instructor work load and increased simulator reality. The method has the potential for development to manoeuvre ships at sea.

B. A. Colley is now with Plessey Marine, R. G. Curtis is with the Department of Trade and Industry and C. T. Stockel is at Plymouth Polytechnic.

1. INTRODUCTION. This paper describes the results of a survey carried out to investigate the views and practices of mariners when navigating in the vicinity of offshore installations in the North Sea.

This paper attempts to explain the development of a method to quantify navigational risk within European waters as a part of the COST 301 project. The objective of this project, partly funded by the EEC and partly by the member countries and a few other European countries, is to increase marine safety and to prevent pollution in European (coastal) waters by shore based aids to navigations. The methodology of this study is explained. The analysis of the collected data regarding traffic and casualties is given. The probability of a collision and a stranding is determined.

The authors are all members of working group 2 of COST 301. Ir. Glansdorp and Captain Tresfon are from the Netherlands Maritime Research Institute, Dr Goodwin is Head of the Mathematics Department at the Polytechnic of North London and Professor Kemp is former Head of the School of Navigation at the City of London Polytechnic.

1. INTRODUCTION. At the 30th Session of the International Maritime Organization (IMO) Sub-committee on Safety of Navigation, held in July 1985, agreement was reached on some further amendments to the International Regulations for Preventing Collisions at Sea, including some amendments to the rule relating to navigation in or near traffic-separation schemes (Rule 10). These amendments will subsequently have to be approved by the Maritime Safety Committee and finally, in November 1987, by the IMO Assembly. Provided there are no objections to the proposals the amendments are likely to come into force in 1989.

1. INTRODUCTION. The North Atlantic air traffic system is the busiest and most important long-range system in operation today with a current total of 127 000 flights“annum. The combined effects of the total flight time and the difference in time zones on either side of the Atlantic makes it desirable for most passengers to fly westward in the day-time. Conversely, it is most convenient (or least inconvenient!) to fly eastbound during the hours of darkness. Thus the Atlantic traffic system is strongly tidal with the flow predominantly (though not entirely) westbound during the day and eastbound overnight. Currently the central core of the traffic in the busiest hours is organised into a parallel track structure – the Organized Track Structure (OTS), though nearly half the aircraft operate so-called random routes clear of the OTS.

The aircraft referred to in the title are the Airbus Industrie A 310, the Boeing 767 and the Boeing 757. The paper has been written in conjunction with representatives from British Caledonian Airways, Britannia Airways and British Airways, airlines which are currently operating these aircraft. I am indebted to the following for their contributions: Captain Stuart Grieve (Chief Pilot, Britannia Airways), Captain Chris Norman (Britannia Airways), Captain Brian Myers, (Chief Training Captain A 310, British Caledonian Airways), Bill Grice (Chief Development Engineer Avionics, British Airways), Captain Rod Fulton (Flight Training Manager 757, British Airways) and Captain Paul Woodburn (Flight Manager Technical 757, British Airways).