The Swedish National Administration of Shipping and Navigation together with the Port of Gothenburg Authority decided in 1980 that in order to increase the safety level by providing shipping with improved navigational information, a new Vessel Traffic Centre should be introduced. The decision was based upon a number of considerations. The Port of Gothenburg handles 30000 vessels each year, the total volume of cargo being of the order of 22 million tonnes. Taken individually, fully loaded vessels entering the port can exceed 225000 tonnes deadweight with a length overall in excess of 325 metres. The crude oil discharged at Torshamnen, within the Gothenburg port area, supplies over 30 per cent of the oil requirements of the Swedish nation. In addition to the tanker trade, Gothenburg has a large ro-ro/container capacity and the ferries calling at the port carry three and a half million people per annum.

Collins Government Avionics Division (CGAD) of Rockwell International became involved with the Navstar Global Positioning System (GPS) in 1974. Since that time, the division has accomplished several key milestones in the development of GPS user equipment including the first transatlantic flight of an aircraft using GPS signals.

This second Matthew Flinders Memorial Lecture, in a series sponsored jointly by the Royal Institute of Navigation and the Hydrographic Society with the cooperation of Lincolnshire and Humberside Arts was presented at the University of Hull on 11 May 1983 with Sir John Dudding, Chairman of Lincolnshire and Humberside Arts in the Chair. The first lecture, presented by Rear-Admiral G. S. Ritchie in April 1974 (Journal27, 3) on the bicentenary of the birth of Matthew Flinders, described the hydrographic work of this exploring navigator. Miss Ferrar concentrates on the graphical records of Flinders's Australian voyages.

When Marco Polo made his journey to China, overland from Venice in the thirteenth century, the lands around the Pacific Ocean were wholly unknown to Europeans. But the silks and spices with which he returned sowed the seeds of the quest for a sea route to the ‘Spice Islands’ which was to be one of the mainsprings of exploration for nearly 500 years. The Spaniards crossed the Atlantic. But instead of finding themselves on the coast of Asia as they had expected they discovered the lands (and the wealth) of the Aztecs and Incas, and their explorations extended along the Pacific coasts of Central and South America from Mexico to Peru. The Portuguese found their way around southern Africa and across the Indian Ocean to South-east Asia, where they attained their objective and established a lucrative trade with the Spice Islands. Sailing ship routes depend upon the direction of prevailing winds, so the outward voyage took them eastwards from the Cape of Good Hope and then northwards to their destination. The homeward crossing of the Indian Ocean was in more northerly latitudes.

Since drilling for oil and gas began in the North Sea in the mid 1960s, the possibility of merchant ships colliding with offshore platforms or rigs, has been of concern to both government and operators. There are nearly 100 fixed and floating installations in the UK sector of the North Sea; they vary in size, location and type of construction, but in all cases, collision would pose serious risks to life, pollution and loss of production. Some platforms are near busy shipping lanes and some have several hundred personnel on them at certain times.

The Geostar satellite navigation system is designed to provide a number of user services through inexpensive terminals (transceivers). The services include precise positioning, location radio (the reporting of position back to a fleet headquarters), digital message transmission both send and receive, and connection to non-Geostar digital communications systems through a single node point. A number of additional user services (terrain and shoreline avoidance, warnings of hazards to navigation, ship or aircraft collision avoidance, emergency location and rescue communications, etc.) are provided relatively inexpensively because all messages and positionings in Geostar flow through a single location where powerful computers are available.

The purpose of this paper, which was presented at a joint meeting held in London with the Nautical Institute on 1 December 1983, is to give an account of the development of Dynamic Positioning from its inception to the present day, a simple description of the principles on which it works, and makes some predictions about its future.

Dynamic Positioning (DP) has been defined in various ways. For the purpose of this paper it will be denned as ‘The ability to hold a vessel in its desired position automatically without the use of physical restraints.’ Physical restraints are ropes, cables, anchors or any other items which connect the vessel to the bottom or to a fixed structure, be it an offshore installation or quay. The word ‘automatically’ means that manoeuvring control must be achieved without manual input.

In this last communication to the Journal, the late Wing Commander Anderson, whose book Animals as Navigators is reviewed on p. 146, discusses the natural sensors by means of which man may control his (purposeful) motion from place to place.

The qualification ‘human’ can convey many things. It could cover the impact of human characteristics on various systems, including the most sophisticated, but we shall use the word to mean that navigation information is garnered by the human senses without the aid of anything that has been manufactured. We shall exclude artificial sensors to provide control and not even accept a marching compass to guide the motion. There will be no printed map to give position and no watch to register time.

Lewison gave a brief outline in modelling of marine traffic flow and gave four possible definitions of the ship to ship encounter as well as developing his own optimal criteria. Barratt has been working on the concept of an encounter for several years and has developed the postulates given by Stratton in a presidential address to the Royal Institute of Navigation in 1971. It is interesting to note that Lewison1 distinguished between a ‘ship domain’, which is the area around a vessel that it is observed to keep free of other traffic and is estimated in terms of the actual density of shipping observed to occur around a vessel, and an ‘encounter area’, which is a radius traced out around a ship in the different directions from which threats may come and is the desired area which the vessel should try to keep clear. The nicety of the ‘encounter area’ is that it is generated in terms of mathematical models and in quantitative terms, and can be reasonably easily established; but it totally ignores any human element or navigators' preferences, whereas the ship domain takes both these factors into account and can only be established after long observation of actual traffic behaviour.

This paper, which discusses a preliminary development of a microcomputer-based navigation system for the fishing industry, was presented at the Oceanology International Congress at Brighton in March. Dr Coates is at the University College of North Wales, Mr Dye and Mr Knox with the Sea Fish Industry Authority.

The history of the sea-fishing industry is one in which success has only been achieved at the price of experience, painfully gathered as a consequence of abortive fishing trips or damaged gear. A detailed knowledge of conditions on the sea-bed, in particular preferred fishing areas and sea-floor obstacles such as wrecks or sand-pinnacles, is clearly of paramount importance in maintaining commercial viability. At the present time, for the requirements of the UK Sea-Fishing Fleet, such specialist information is available in the form of the widely used ‘Kingfisher’ chart series. With the advent of cheap, yet powerful microcomputer systems, the possibility now exists to create a data-base version of the Kingfisher Charts, thus offering the advantages of rapid updating of information and convenient wheelhouse presentation of user-selected chart features by means of a video monitor.

The fisherman's task in navigating his craft are threefold:

(i) to guide his craft safely and by the most direct route between his terminal ports and the fishing grounds;

(ii) to shoot, tow and haul his fishing gear in such a manner as to prevent it being damaged or becoming fast to any obstruction on the seabed;

(iii) to search for aggregations of commercial fish species and by lures, snares and the use of towed nets to capture viable quantities of the fish located.

The navigation to and from the fishing ground poses the same problems as for other marine craft, but once on the grounds, using towed or encircling nets, the position of the nets, not only horizontally but also in the vertical plane, are as much his concern as is the position of the parent vessel. Most fishing grounds are situated where there are irregularities in the seabed topography or where oceanographical factors provide a rich feeding area for a range of fish species. Alternatively many fish species carry out an annual migratory journey to their spawning areas or towards more favourable environmental conditions, their shoaling behaviour at this time making them particularly susceptible to mass capture.

This paper examines the evolution of the arctic submarine and the ever-increasing scientific and commercial potential which have accompanied this evolution over the past 340 years. It is a sporadic history of arctic submarine ideas, concepts and actual experiences with vessels at sea. It happens to be a history that is largely American, with important additions as a result of the experiences of the Germans, Soviets and the British, particularly during World War II. Finally, it is a history in which five early visionaries in particular stand out: Bishop John Wilkins of England; Jules Verne of France; Professor Anschutz-Kampfe of Germany; the submarine designer Simon Lake, of the United States — whose influence extended over four decades until well into the twentieth century; and Sir Hubert Wilkins of Australia.

The mathematical collision risk model developed by Reich can be used for evaluating the current air traffic control (ATC) separation minima. This model requires such parameters as volume of traffic, navigational errors of aircraft and the structure of routes. The navigational errors are closely related to the probability of overlap, which is one of the most important parameters for the model.

Distributions of navigational errors have been studied by many researchers since the advent of the collision risk model. Because data collection on the navigational errors in the vertical dimension is expensive and time-consuming, there are few examples of observed data. Thus, at present, data on the probability of overlap in the vertical dimension are not available in a large enough sample to derive any conclusions.

Vessel damage incurred by ships manoeuvring in restricted waters and during berthing operations has identified a need for a precise navigation system that would give a master positional information of a high degree of accuracy in a simple visual manner. Such a system would improve operations in marginal weather conditions and decrease turn-around time for the regular port user.

Drawing upon its offshore survey and positioning experience, Wimpol Ltd has developed a precise vessel positioning system which meets a demanding specification with regard to accuracy, reliability and simplicity of operation.

A symposium was held in London on 6 December 1982 under aegis of the Institute with the traffic management fuel conservation working group to discuss meteorological forecasting and its application in terms of fuel saving. The chairman was J. C. Morrall, Chief Scientist of the Civil Aviation working group. In the United States, the work of Dr R. Steinberg of NASA on the penalties of imperfect forecasts and possible benefits from an improvement was of considerable interest. V. W. Attwooll and L. Bennett of the CAA had also studied penalties from North Atlantic forecasts. Part of the UK civil avionics programme was concerned with the forecast of winds applied in particular to 4-D time-slot following; this was. described by R. C. Rawlings of RAE Bedford. Mr C. Flood, of the Meteorological Office, finally presented prospects for improved forecasts.

Traffic separation schemes have been established all over the world with the aim of reducing the danger of collision. Field observations have shown that despite the adoption by IMO and the laying down of the schemes on nautical charts a good many vessels do not comply with the steering and sailing rules applicable at traffic separation schemes. This paper attempts to review the apparent difficulties met. Some suggestions for improving of the situation are made.

The separation of traffic into two streams moving in opposite directions has been introduced with the aim of reducing the incidence of collisions. Such a measure results in a decrease of the rate of encounters and an almost total elimination of head-on or fine crossing meetings which are considered dangerous especially in restricted visibility. Investigations have confirmed the effectiveness of the measure in achieving the purpose provided that the steps taken are reasonable from a practical point of view.

An article entitled ‘Defining the Close-Quarters Situation at Sea’ in this Journal (36, 454, September 1983), described how certain manoeuvres made by ships could safeguard against close-quarters situations developing at sea and, when circumstances demanded, these manoeuvres could ensure compliance with Rule 19(e) of the Collision Regulations.

Basically it was suggested that engines should be stopped when the distance between two such approaching vessels was N nautical miles, which was pre-calculated. If that action appeared insufficient, full astern power should be applied after an interval of Δt minutes had elapsed or, at the latest, when the separation distance between the two vessels was not less than Ab(SP) nautical miles.

Ever since man first ventured to sea, he has needed to know not only where he was in relation to the land but also what dangers lay hidden below the surface, and what courses to steer in order to avoid these unseen dangers so as to arrive safely and speedily at his destination – making due allowances for the effects of tidal streams and currents.

Because his sea-maps were working documents, usually exposed to a hostile environment, fewer such old records have survived than is the case with old land maps. Undoubtedly, whilst many early voyages of exploration emanated from Europe, it should not be forgotten that in the – to European eyes – ‘unexplored’ parts of Asia and the Pacific, similar voyages were being made. However, as trade developed between Europe and the rest of the world, hydrographic surveyors from Europe began to record the information needed along the various trade routes.

A large percentage of the air traffic flow in the UK is associated with movement to or from other European countries. It would therefore be unrealistic to consider further development of the UK air traffic control network other than on an inter-European basis, although this would necessarily raise many problems.

Throughout Europe, during the period since the Second World War, the various nation states have developed their individual air traffic control systems based on national centres and extending to the boundaries of their own Flight Information Regions (FIR). The movement of aircraft across the FIR boundaries of neighbouring states is at present governed by a series of bilateral agreements, whilst attempts to reach international agreement on integration of the European ATC system have not as yet met with much success.

Before 1972 the Collision Regulations were drafted so as to enable a court to decide which vessel was to be blamed rather than to assist the mariner to avoid collision. The new Regulations have been drafted primarily to assist mariners to prevent collisions at sea. Even so, actions to avoid collision required by the Rules are described in abstract terms because of the variety of visibility, sea-room available, manoeuvring capability of the vessels and the nature of the encounters. In order to help mariners understand the requirements of action to avoid collision both in quality and quantity, some reference data are recommended by experienced mariners and researchers. This paper is an attempt to introduce a study on quantification of the term substantial action to avoid collision and the distance of last-minute action in turning to avoid collision.