Any comment on arctic navigation must be broadly based since the ability to conduct voyages in ice-infested waters is influenced by many factors. The traditional technique of exploiting open channels in the ice is now no longer adequate and there is an increasing need for vessels to force ice in order to reach places and to carry out activities well inside the boundaries of the permanent ice cover during parts of the year when the sea ice is at its maximum extent.

This paper, which was presented at an Ordinary Meeting of the Institute held in London on 19 November 1980 with the President in the Chair, first outlines the arguments for simulators for use in training and research. The technical problems encountered in simulating ship behaviour are discussed, and the various engineering approaches which have been used for actual simulator construction are described. An account is given of experience to date with ship simulators in the UK, and the future prospects for marine application of simulator methods are discussed.

I am very pleased to be with you on this occasion which gathers annually the friends and admirers of Professor Eva G. R. Taylor to honour her memory. My presence here reflects the globe-circling impact her work continues to have, as more and more people from many disciplines rely on her varied contributions. As for the distance of the echo to her work, I qualify, coming from close to half way around the globe, or from Long. 110° 58′ 08″ west of Greenwich. I have elected to talk about Felipe Bauzá who, on an autumn day of 1823, presented himself to the Royal Geographical Society here in London, some way north and east from his birthplace, Palma de Mallorca, and his port of departure, Gibraltar. For he was one of the Spanish liberals with a price on his head under orders of that treacherous puppet of the Holy Alliance, Ferdinand VII.

Any device having a property which varies as a result of its being rotated in space can, in principle, be used as the primary sensor of an inertial navigation system. A wide range of devices and properties has received attention with this aim in view. The spinning-wheel gyroscope has, to date, proved the most fruitful but a number of ‘exotic’ types of gyro show promise. The discovery that the atomic nucleus can, under certain conditions, behave like a spinning mass gave birth to ideas of a nuclear gyro of some sort. The further discovery that some nuclei possess magnetic properties opened the way to nuclear magnetic resonance and offered a method of communicating with the minute spinning masses.

This paper was presented at a meeting of the Institute in London on 18 February 1981 with Dr J. F. Kemp in the Chair. Captain Alderton discusses a variety of criteria for assessing economic optimal speeds and shows how sensitive these optima are to such constraints as port time, voyage distance and bunker costs.

The expression ‘optimum’ is frequently used very loosely and one often finds that the factor under consideration is only being optimized with reference to some, not all, of its dependent variables. A truly optimum speed for a ship can only be achieved by considering:

(i) What speeds the ship can actually achieve, taking into account various mechanical constraints, the state of the hull (fouling), the draft and the effect of the weather.

(ii) What speeds we would like the ship to achieve taking into account the costs, the profits and the pressure of schedules.

When measurements and observations are made using a radar simulator, the researcher assumes that mariners behave in the same way, whether they are handling a simulator or a real ship. This paper, which was presented at an Ordinary Meeting of the Institute held in London on 22 April 1980, investigates whether this is a reasonable assumption.

In recent years much time and energy has been spent investigating marine traffic flows and casualties in major seaways and rivers around the world. This paper presents data relating to marine traffic from the Humber light-vessel to the Hull Roads (Fig. 3), an intermediate seaway serving a number of small to medium sized ports.

Human error is a contributory factor in many accidents at sea. To explore some of the variables involved, a study of simulated ship-handling was undertaken. This investigated the possibility of predicting behaviour at sea from the personality of the individual ship-handler. Results indicated that, in particular, the scores of the seafarers on one simple test correlated with the distances at which they took avoiding action, and that, in general, the relationships between personality factors and ship-handling behaviour was a promising line to pursue.

When vessels are required to adhere to a routing scheme involving long segments of one-way traffic, as in the Dover Strait, the overtaking of one ship by another can result in some degree of hazard and nuisance as well as loss of time. The frequency of such manoeuvres would appear to depend on a number of factors, such as the density of shipping in the lane, the domain size of individual vessels and the speed and lateral-distribution profiles of the traffic. From general considerations it seemed likely that the manner in which overtaking manoeuvres are made, with regard to the presence of other ships in the vicinity, might have some effect on their frequency and extent. It therefore seemed worthwhile to investigate theoretically any change or reduction which might result if overtaking ships were to take account of the presence and location of other vessels in the vicinity when the decision whether to pass to port or starboard of a ship being overtaken was about to be made.

Captain Barker's paper was presented at a one-day seminar on The Selection and Display of Navigational Information at Sea, jointly organised by the Royal Institute of Navigation and the Nautical Institute in London on 11 December 1980.

It does not seem so long ago since a shipmaster could not do better than proceed at utmost speed, mindful of sea conditions for heavy weather damage and of fog, for a successful conclusion to a commercial venture. Today the cost of bunkers may exceed the income earned on the freight. Commercial organizations carrying their own cargoes have always had to operate at speeds that relate to freight levels, but owners with their ships on charter, who were never very concerned in conserving bunkers, are now more closely scrutinized on the way they operate their ships, and particular attention is paid to the speed-consumption curve.

Due to the very low power-to-weight ratio found in large deadweight ships, their high inertial values and the very long reaction time to manoeuvring commands, difficulties often arise in achieving entry to the berthing area at an exactly pre-determined speed over the ground.

This paper describes a dynamically programmed optical aid to help the navigator achieve exactly the prescribed speed over the ground as he decelerates along his traverse or intended track when approaching his terminal or swinging area. The authors are consultants to AGA Navigation Aids Ltd who have developed this device.

Over the last decade or more, some very significant changes have occurred in the general requirements relating to the handling and manoeuvring of certain classes of modern vessel in the approach to their terminal berth – whether jetty, single-buoy mooring or even when coming to anchor. The economy of size in the bulk trades has probably had the most profound effect. This often reduces the power/weight ratio of the vessel itself to a very low order. In turn this has led to radical adjustments in techniques of ship handling in the final approach phases, due to the long response time between command instructions and reactions to these by the vessel itself. When considering the inertia of a vessel of 220000 tons deadweight or more – where the feasible deceleration or rate of change of speed is also of a low order – we can see the difficulties met with when endeavouring to enter the berthing area at an exactly required pre-determined speed over the ground (as opposed to speed through the water) often as low as one tenth of a knot or less.

The total loss statistics for 1979, published in the Casualty Returns of Lloyd's Register of Shipping, provide further evidence of the increasing disparity between the safety records of vessels operating under different flags. Statistics of total losses are likely to be almost completely accurate, especially for ships of over 1000 tons gross, and can be used as the most reliable indication of trends in serious marine casualties. This review of recent total losses will be restricted to trading ships of over 1000 g.r.t.

The year 1981 marks the fourth centenary of the birth of Edmund Gunter who, during his relatively short life, played a dominant role in England in the advancement of navigation. Born in Hertfordshire, of Welsh parentage, Gunter was educated at Westminster School before entering Christchurch College, Oxford, where he graduated BA in 1603; MA in 1606; and BD in 1615, in which year he was presented to the living at St George's, Southwark.

As early as 1603 Gunter had written an account of a ‘New Projection of the Sphere’ which was circulated in manuscript among some of his mathematical acquaintances. This appears to have gained for him the friendship of Henry Briggs, the first Gresham Professor of Geometry and a brilliant mathematician best known for having been first to suggest a table of logarithms to base 10 – ‘common logarithms’, as they are now known.

This paper is an abridgement of the paper presented at an Ordinary meeting of the Institute held in London on 20 February 1980 with Captain G. Dudley in the Chair. Captain T. C. Haile of the School of Navigation, City of London Polytechnic, illustrates some past instances when political issues have involved hydrographic surveys, before discussing the delicacy of position fixing in off-shore oilfields.

The political implications of hydrography can be traced back at least to the close of the fifteenth century, when the great discoveries of the Portuguese, promoted by Prince Henry the Navigator, and the discovery of America by Christopher Columbus brought to a head the rivalry between the two powers for the control of the Spice Islands of the east.

This paper was presented at a meeting of the Institute in London on 25 May 1980 with Captain S. S. D. Jones in the chair. Mr Page assesses the role of air navigation as one factor in coordinated flight planning, through the application of modern techniques, to secure maximum efficiency in airline operation and in the conservation of fuel.

This paper presents an airline view of developments in aircraft navigation and planning. It considers aircraft navigation in the widest sense together with the current change in emphasis in navigational requirements. Present technology can produce navigational systems of almost any desired accuracy – at a price. The cost of such systems, together with the requirements of ATC, will dictate the choice.

The literature of the recent past concerned with the collision avoidance regulations cannot be regarded as the model of rational scientific discussion. Subjective arguments based on personal experience of particular situations and very general mathematical analyses are pitted together without any generally accepted criteria by which to judge them. Obviously both mathematics and experience have great relevance to this geometrically simple, but operationally involved, problem. One step nearer a rational optimization of a set of regulations defining action during collision avoidance would be a formalization of the criteria a successful rule of the road must meet, and of the operational difficulties it faces. The present regulations, for instance, suffer from several logical inconsistencies which are difficult to describe in simple mathematical terms.

This paper was originally presented at the Second Symposium on Satellite-Doppler Positioning in Austin, Texas in January 1979.

The application of doppler satellite technology to ice-movement studies requiring high-quality positional determination ( ± 1 m) has proved of great value in remote areas of Canada. Potential oil and gas anomalies in the Arctic Islands, hundreds of kilometres from land, can now be successfully monitored with regard to ice-floe movement by remote methods on an almost daily basis. Extensive field tests conducted in the Calgary area during the fall of 1976 showed that daily movements as small as 1 m could be detected with high-quality satellite receivers using rigorous three-dimensional multi-station computer processing methods.

It has for some years now almost been folklore that the marine traffic situation in the Dover Strait is one of great potential danger. Very considerable efforts have been made to alleviate the situation. There is a complete traffic separation scheme (the first in the world), there is continuous radar surveillance both from England and France, there are routine broadcasts on v.h.f. to warn mariners of any navigational problems, and there is now a system whereby certain ships report-in. Concurrently with all this activity, the accident rate has dropped significantly over the last decade, especially in fog, and it is a reasonable inference that the reduction in the number and severity of accidents is attributable to this activity.

But patterns of navigation change, and it is necessary for marine administrators to be aware of problem areas as or before they arise so that marine management measures can be introduced when appropriate. Factors to be taken into account are the volume and characteristics of the traffic, the difficulty of navigation and the accident record. One of us has drawn attention to the traffic situation off East Anglia and suggested that a prima facie case for some remedial measures had been made. This paper examines the available evidence in more detail.

First, an account is given of the accident record in the area under consideration (Figs 1, 2) over the last 10 years. Both the numbers and severity of collisions and strandings are discussed.

In this article formulas useful for the calculation of aircraft mid-air collision probabilities at intersecting air routes are developed. The aircraft overlap density, a key parameter in the calculation, is expressed as a function of the intersection angle of air routes, aircraft speeds, the nominal separation, and parameters in the position-error distribution. Two representative probability models for position errors are used to illustrate the computational procedures suggested. A method of approximation over large navigation systems is also proposed.

The calculation of aircraft mid-air collision probabilities is an important step in the design of air-route structure and is a key element in the specification of separation standards and minimum requirements of facilities reliability and accuracy. A thorough analysis of collision probabilities for long-range parallel air routes over oceanic areas was reported by P. G. Reich in three research documents and in a series of papers published in this Journal in 1966. Analysis of collision probabilities at intersecting air routes typical in off-shore and continental areas, however, has not been fully explored to date. The only direct reference available on this subject appears to be the work by Bellantoni,7 in which a collision problem was formulated in the three-dimensional space and was apt to deal with airport terminal landing or take-off situations. For circumstances where horizontal linear air routes intersect one another at preassigned positions, the analysis provided by Bellantoni needs to be simplified and refashioned for use in extensive applications.