Between April and about September 1977 almost all the present buoys in the southern North Sea, Dover Strait and eastern part of the English Channel will be changed and a completely new system introduced in an area much used by international shipping of all types. Why has this come about and how can the new system be recognized on charts and in the water? What are the most significant changes and where will the system be applicable? The answers to these questions are given in the Hydrographic Department's new publication NP 735, IALA Maritime Buoyage System A, Edition 1, 1976, which is now available from Admiralty chart agents. It should be studied carefully by all who go to sea or are concerned with marine operations in north-west European waters.

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.

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

Modern ship control and navigation systems involve a complex variety of intricately interwoven electronic, electrical, mechanical and hydraulic devices. It has become appropriate therefore to devise a convenient method for representing mathematically the dynamic characteristics of these systems and the elements which comprise them, so that block-diagram modelling can be implemented. This is ideal for displaying the interrelationships of such systems pictorially and has the added advantage of simplicity and of indicating realistically the actual processes which are taking place, as the models refer to the relationship between mathematics and the real world.

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.

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, last year, you elected me to be your President, you placed upon me the duty of delivering before the Institute the tenth Presidential Address. My predecessors in this office have been men of considerable scientific and administrative distinction, able to talk with authority in their respective fields of learning. I, however, come before you mainly as a practitioner of air navigation, the first such to be your President, concerned with the practical business of ‘how to get there’ in an imperfect, and only partly understood, world, rather than with the elegant demonstrations of a theoretical technology. The duty of preparing a Presidential Address, though onerous, has its compensations. It is the one occasion in the Institute's year when a speaker has the right to stand up before you, and to muse and speculate on controversial matters, rather than to present an account of completed work. A recent writer speculating on the future growth of air transport took as his motto: ‘Behold the turtle—she advances only by sticking her neck out’. This is true not only of turtles, but exemplifies the spirit which is needed to meet the challenge of the future: it is in such a spirit that I offer this Address.

The purpose of this paper is to identify and discuss official British general charts of New Zealand. The principal development period of the general chart ended when the fourth chart was published in 1885; this edition was not superseded until 1964.

It is not often that a drama of the sea provides the main story in the news, and it is still more unusual for such an occurrence to continue to occupy the headlines; but the Torrey Canyon disaster was unique in having done this for a whole month and more. Day after day, there was a slow and inexorable increase in the area affected by the catastrophe and in its duration: while such protective measures as could be improvised could seldom do more than repair damage that it was impossible to prevent.

Among many records of the first circumnavigation of the globe preserved in Spain is the log-book kept by the pilot who brought the Victoria home—under the command of Sebastian de Elcano. This pilot's name was Francisco Albo. He signed on in the first instance as master's mate of the Trinidad, Magellan's own ship, which did not return. Although a native of the island of Rhodes, he was thoroughly grounded in the Portuguese method of navigation—by observation of the noon Sun. It involved the use of a four-year table of declinations, and an English version of this very table and instructions was presented to Henry VIII about 1540 by Roger Barlow, who was urging an English participation in the new discoveries.

The problem considered in this note is that of determining an upper limit for the chance that an error will not exceed some given quantity. Where the pattern (or frequency distribution) of the errors is either known or assumed, the solution to the problem is merely a matter of calculation. This note starts by making the minimum assumptions about the pattern of errors, and then examines the effect of gradually increasing the restrictive assumptions.

This, and the following three papers, were first presented at GNSS 2000, the Third European Symposium on Global Navigation Satellite Systems held in Edinburgh, Scotland from 1st to 4th May 2000.

This paper presents the methodology and a practical implementation approach to perform GNSS Safety Assessment and Certification with due consideration of the satellite navigation system users. It places Galileo GNSS in a total system that includes vehicles, on-board equipment, crews and traffic controllers and defines the necessary organisation for implementing safety analyses right from the early design phases of navigation systems. Civil aviation has very demanding requirements based on objectives for air navigation safety. It is much better organised on a worldwide basis than other GNSS users and is considered in this paper as the leading study case. Some methods are then proposed to build a bridge between all user organisations and to set up a common approach to certification.

Estimating the collision frequency of ships (F) is important for assessing collision risk on waterways. To date, F has been estimated as the product of the number of collision candidates $({N_{a }})$ and the causation probability $({P_c})$: $F = {N_{a}} \cdot {P_c}$, where ${N_{a }}$ represents the number of collisions that occur when related ships continue on course with no intervention, and ${P_c}$ is the probability that collision avoidance fails. Fujii developed a general method and Pedersen formulated it to estimate ${N_{a }}$ in an intersectional area. Their method is generally called ‘the geometric method’ because collision candidates are estimated only from the geometric relationship between two ships. The method has been used in many projects to estimate F in waterways; however, its use should be limited to intersection angles ranging from 10° to 170°. This paper presents a method, statistically verified by computer simulation, that can be used at all intersection angles to overcome this limitation. Moreover, it demonstrates strong agreement with Pedersen's method at intersection angles of 10° to 170°.

Liquefied natural gas (LNG) offers negligible NOx and SOx emissions as well as reductions in CO2 compared with other liquid hydrocarbons. LNG is a significant player in the global energy mix, with a projection of 40% increase in demand for the next two decades. It is anticipated that the expected rise in demand will cause the fleet of LNG carriers (LNGC) to expand. This work concentrates on steam-powered LNGC, which accounted for 47% of the LNGC fleet in 2018. It performs an empirical analysis of continuous monitoring data that provide high levels of accuracy and transparency. The analysis is done on data collected from 40 LNGCs for over a year to estimate the fleet's operational profile, fuel mix and energy performance. The findings of this work are relevant for bottom-up analysis and simulation models that depend on technical assumptions, but also for emission studies such as the upcoming Fourth International Maritime Organization Greenhouse Gases study.

The United Nations Convention on Law of the Sea (UNCLOS) came into force on November 18, 1994 to provide the legal framework for maritime boundary delimitation. Understanding the geomatics aspects of UNCLOS is vital for coastal nations to claim the ownership of the natural resources within the limits of their Continental Shelf. This paper discusses some of the geomatics aspects of UNCLOS, namely the geodetic and uncertainty issues. A case study for Egypt's outer limits is also presented.

This, and the following four papers, were first presented at the NAV99/ILA28 Conference on ‘Loran-C, Satellite and Integrated Systems for the 21st Century’ held at Church House, Westminster, London, 1st–3rd November 1999.

Just 25 years ago, the author presented a paper at the 30th Annual Meeting of the United States Institute of Navigation (ION) entitled ‘Radionavigation in North America, the Next 25 Years’. The paper received much attention and was given the ION's Burka Award for the best paper of the year. The author attempted to predict the worldwide implementation of Loran-C and Omega while acknowledging that satellite technology was on the horizon. ‘Global Radionavigation – The Next 50 Years and Beyond’ builds on the previous paper and is an attempt to define the future of global radionavigation based upon a mix of terrestrial and satellite systems. The time it takes for satellite systems and augmentations to mature and the reasons for this extended period provide the foundation of the paper. Also discussed are: the time to achieve a full constellation of space vehicles having signal specifications that meet the requirements for safety-of-life, the political complexities to achieve international harmonisation of service, and the use of a common worldwide protected frequency spectrum. The need for terrestrial complements is presented from the standpoint of supporting satellite systems and as a back-up in the event of loss of satellite services.