Adverse effects of intoxicated driving have been well documented over the years, with clear conclusions. In addition, it is evident that the cognitive and neurological functions and reaction times deteriorate with the consumption of alcohol. Addressing the lack of literature on the subject, this paper focuses on studying the effects of alcohol on manoeuvring, navigational and decision-making ability in ship navigation. Ten participants – five cadets and five experienced navigation officers – volunteered and carried out a standard manoeuvre using a computer-controlled vessel simulator, under three different blood alcohol concentrations (0⋅00%, 0⋅05% and 0⋅08% BAC). Results from the simulations were used to assess the performance and the decision-making ability of participants under the influence of alcohol. In addition, the responses and behaviour of the simulated vessel when the navigators were intoxicated were analysed. Workload experienced by participants during the simulations were also assessed using the NASA Task Load Index. Findings of this preliminary study proved that the ability to make the correct decisions at the right time was drastically deteriorated when the blood alcohol concentration was increased.

The purpose of an instrument let-down is to bring an aircraft past all hills and obstructions to a particular position at low height. If the pilot follows the correct procedure, the aircraft will obviously clear the hills and obstructions. But owing to various interruptions and distractions, difficulties of reception or the need to give partial attention to other duties, he is often unable to follow the procedure exactly; he will then want to know whether departure from the procedure requires immediate rectification, or whether he is at liberty to return gradually to the correct path. A badly working radio aid, or some other difficulty, may make it necessary to abandon a partly completed approach; he will then want to know the best way to extricate his aircraft from a possibly dangerous situation. Furthermore, the pilot often has to improvise an ‘intermediate procedure’, to connect between his arrival over the aerodrome and the beginning of the let-down. For these reasons he needs to know the positions of the hills and obstructions in relation to the let-down; and the only way to present this information to him quickly and unambiguously is by making hills and obstructions the principal features of let-down charts. The local knowledge possessed by pilots of scheduled services does not lessen the need for an effective presentation of this feature on the charts, as it is precisely when landing at unfamiliar aerodromes that the charts will be most used.

When studying the influence of navigational accuracy on collision risk, operating economy, or traffic organization it is necessary to distinguish between monitored and unmonitored traffic. With the monitored traffic the relative separation between aircraft is detected by the monitor and can be controlled by it. This is a closed-loop concept. With unmonitored traffic the separation is provided by procedural clearance of the flight plan. This is an open-loop concept.

This paper formed the 1987 Anderson Memorial Lecture, and was presented to the Bristol Channel branch on 24 March.

This paper contains a brief survey of a series of instruments which have been developed for use in sailing yachts. It then outlines the principles of two computers; one navigational, the other for sailing performance indication. It does not cover radio navigational aids, echo sounding or radar. The data requirements are: 1. Navigational, comprising distance run through the water, heading, leeway angle. 2. Functional, comprising speed through the water, direction of the apparent wind and speed of the apparent wind.

For measuring distance run, the classical towed rotator type of log, fitted with a mechanical or electro-mechanical revolution counter has been largely superseded in racing yachts by logs employing through-hull sensors on account of drag considerations and the inconvenience of having to shorten the line when sailing slowly in shallow water. It still finds favour in cruising yachts on account of its generally lower price and its simplicity.

This paper discusses the development of Electronic Chart Display and Information Systems (ECDIS) and Electronic Chart Systems (ECS) generally. The role of ECDIS and its implementation is also discussed and compared with the trend by manufacturers to the alternative ECS. International developments in relation to ECDIS and ECS initiatives are looked at briefly and a view on the relationship between government and commercial organizations is presented with reference to the safety of navigation.

This paper, and the following paper, were presented at the 8th Congress of the International Association of Institutes of Navigation held in Beijing, 6–11 September 1994.

Until its nationalization in 1956, the physical limitations of the Canal had greatly influenced world shipowners with regard to the sizes of ships built, particularly oil tankers. Following nationalization, in an era of cheap oil and transport costs, shipowners took the initiative and began to build large tankers. Mindful of the effect that such changes would have on the tonnage of oil transported through the Canal, the Suez Canal Authority began a programme of expansion in 1958 which was to be executed in two stages. The first stage was completed by February 1964 and consisted of widening and deepening the Canal so that ships with draughts of 38 ft could be accommodated, thus allowing vessels of 60,000 d.w.t. to transit fully loaded. The second stage of development was intended to deepen the Canal to accept vessels of draughts up to 40 ft, corresponding to ships of 70,000 d.w.t. This work was scheduled to be completed by the end of 1967, but the project was not finished due to the start of the Arab–Israeli war.

Since the last Institute meeting on the Admiralty chart in 1967 the compilation office, formerly at Cricklewood, has been moved to a new building at Taunton, alongside our printing works established there in 1940. Thus, except for a small office in Whitehall, which keeps in touch with the ever changing defence scene, the whole of our organization is now concentrated at Taunton, from where every week between 30,000 and 40,000 Admiralty charts are despatched, through our agents, to navigators in every part of the world.

As readers of the Institute's Journal will know, to mark the 21st anniversary of the Institute a special edition, entitled The Navigation Explosion was published. Papers published in this edition highlight the very rapid advances which have been made during those 21 years as a result of a happy marriage between the ancient art of navigation and modern science and technology.

This paper, which was presented at a meeting of the Deutsche Gesellschaft für Ortung und Navigation held in Berlin on 24 April 1963, briefly discusses some of the factors which will affect navigation and control of supersonic transport aircraft. Attention is directed to the special problems of determining optimum flight path and estimating position and E.T.A. during three phases of the flight: acceleration, supersonic cruise and deceleration.

In 1965, following the Eastbourne Conference, the British, French and German Institutes of Navigation formed a Working Group to make a study of the environment in which the supersonic transport will operate and of its implications for the navigation of such aircraft. The Group's initial task has been one of education, largely through discussion of a series of papers submitted to it. Some of the papers considered have already been published in the Journal (Vol. 19) and a further selection is published below. Table I was contributed by Mr. G. E. Beck. The illustrations to these papers have not all been reproduced.

1. Atmospheric Conditions. It will be useful to distinguish between different kinds of atmospheric influences on supersonic aircraft operations. They may be classed as follows:

(a) Sporadic effects near the ground

(b) Sporadic effects in the free atmosphere

(c) Effects on sonic boom

(d) Effects of atmospheric ozone

(e) Permanently effective atmospheric parameters, such as temperature, density and wind.

I am reminded that this was the title of a paper by Professor W. M. Smart, published elsewhere in 1946, dealing with the rhumb line on the spheroid, by references in recent issues of this Journal to a paper of mine entitled ‘Loxodro-mic distances on the Terrestrial Spheroid’ which appeared in this Journal 32 years ago: the subject crops up every few years.

It is suggested by D. Nicolson (this Journal29, 414) that there is a need for reporting near misses at sea, similar to the system which has been in force for air navigation since the late 1950's. He also suggests that the primary function of such a system would be as a training aid in nautical colleges and training establishments, but that it could also provide statistical evidence. While agreeing on the urgent need for a reporting system I would expect a different order of priorities.

An internationally established system of reporting near misses at sea could serve many valuable purposes. It would indeed provide a useful training aid if the reports were given in full detail. The system as suggested would not, however, be complete since it would not be international in character, and might only flourish in vessels whose officers still require to sit for further professional qualifications. To be statistically valid a reporting system would have to be international and apply to all types of craft, from the warship and passenger liner to the fishing vessel and yacht.

1. Hovercraft Environment. With the exception of the sidewall craft which is unlikely to achieve speeds in excess of 30 knots, all hovercraft depend on their ability to rise clear and free from water drag in order to achieve their high economical speeds. Nevertheless a hovercraft will tend to conform with the surface over which it is travelling. A rough sea produces a rough ride which at speed produces a motion not unlike that of a car going over a series of hump bridges with vertical accelerations in the order of 1½ g—one needs to be strapped into a seat. The most efficient means of propulsion is achieved by using air screws; these are noisy and necessitate crew members using an intercom. Control surfaces, rudder and airscrews are aerodynamic and to reduce air drag the hovercraft is likely to be low in silhouette and give poor all-round vision to the command. The biggest single factor is drift; being aerodynamic and free of water drag, the hovercraft is completely wind borne and in moderate beam winds can track with as much as 45° of drift angle on and turns out of wind can be alarmingly large.

An experiment is described in which colour-coded information concerning the aspect of target ships was provided in addition to a relative-motion radar display. This was compared to the normal relative-motion display alone, while a third condition used the normal true-motion display alone. The performance of twenty-one experienced seafarers on six exercises was assessed by five expert judges as an index of display effectiveness. The method of evaluation was found useful and practical, while user reports were shown to be inappropriate. No overall difference between the three displays was found; the reasons for this are discussed and the conclusion is drawn that training is required to gain the benefit of colour in a display.

Recent statistics are reviewed with regard to deficiencies in standards of seaworthiness often resulting in detention as noted from surveys worldwide. Recent ship loss statistics are analysed, the subject of ownership of Flag of Convenience (FOC) vessels is addressed and FOC registry related to vessel loss data. The increasing age of the world fleets is noted as replacement orders for new hulls have dwindled. Crew costs are discussed and considered in relation to economics and safety of operation. Comparison is made on ship safety between routed and non-routed vessels. Improvements in weather routeing services and safety are noted as a result of employing automated systems.

There are two stages in the determination of position from current observations. The observations are first resolved into positional form on the chart and plotted so as to give either a fix or a position line. When more than two position lines are available, some of the information is redundant and a problem exists of determining the most likely fix. In the case of air navigation, the number of position lines seldom exceeds three, and the determination of position in this case has been studied in a previous article.

When in 1969 the specific task of scheduling shipping movements in and out of a tide-restricted port had been given as an exercise to a group of harbourmasters attending a symposium at UWIST, Cardiff, the varying methods employed and the apparently large workload involved indicated that a formal study of the problem would produce a more rational solution. The early part of the study, by K. D. Jones with the help of his assistant B. J. Moody, was to develop suitable computer programs to automate a scheduling process such that an ideal pre-movement plan could be arrived at, using as criteria the earliest movement times for given ship-draught and available water-depth.