The invention of the balloon was almost a casual affair, unrelated to other contemporary inventions and unheralded by prior developments. The hot-air balloon could have been invented at any time since the mastery of thin textile manufacture, which can be dated well before the Christian era. The hydrogen balloon could not have come about until after Cavendish had isolated the gas in 1766. As it finally turned out, both types of balloon were invented in the year 1783.

Thanks to the development of the real-time kinematic (RTK) algorithm and the emerging Global Navigation Satellite System (GNSS), especially for Galileo and BeiDou-3, reliable positioning accuracy for medium and long-baseline RTK became possible globally. Moreover, with the development of the GNSS receiver hardware, baseline length limitations due to radio-based communications are removed thanks to internet-based communication. In this work, single-baseline RTK, incorporated partial ambiguity resolution with troposphere and ionosphere weighting, using GPS (G), Galileo (E), BeiDou-3 (C3) and multi-GNSS (GE and GEC3), is conducted with real GNSS data of EUREF Permanent GNSS network under three different cutoff angles (10°, 20°, and 30°) for six different lengths of baselines (~50, ~150, ~250, ~350, ~450, and ~550 km). The results show that the multi-GNSS RTK solution significantly contributed to the positioning accuracy and convergence time of the single-system RTK solutions. Based on the results, non-available epoch-wise solutions for the high-degree cutoff angles are more obvious for the single-system RTK, whereas multi-GNSS solutions provide 100% solutions for each cutoff angle and baseline. The results indicate that instantaneous and a few epochs single-epoch ambiguity resolution is feasible for 50, 150, 250 and 350 km baseline lengths for multi-GNSS RTK. Based on the positioning results, horizontal–vertical positioning improvements of multi-GNSS RTK (GEC3) compared with the single-system GPS RTK are found as 50%–37%, 40%–35%, 55%–47%, 53%–54%, 57%–49% and 57%–49% for 50, 150, 250, 350, 450 and 550 km, respectively, under a 10° cutoff angle. For 20° and 30° cutoff angles, the accuracy improvements are much higher. The convergence time improvements (n/e/u) of multi-GNSS RTK (GEC3) compared with the single-system GPS RTK are found as 86/92/75%, 77/67/72%, 75/77/83%, 53/56/52%, 69/49/62%, and 52/45/39% for 50, 150, 250, 350, 450 and 550 km, respectively, under a 10° cutoff angle.

Standards IEC 62288:2014 and MSC.191(79) require information on the displays of shipboard navigation systems to be logically grouped, but only provide limited specification for this ‘logical’ criterion. Meanwhile, complex interfaces and information overload remain as major design issues, being connected to several maritime accidents. To address this matter, a three-phase study was conducted to develop a pattern to organise essential information on Radar and Electronic Chart Display and Information System (ECDIS) displays and their equivalent modules on integrated navigation systems and integrated bridge systems. The first phase involved identifying the information most essential for safe navigation using cognitive task analyses, equipment performance standards and frequency of use. The second phase involved a card-sorting experiment with seafarers (n = 63) to develop an initial grouping pattern for the identified essential information. The third phase involved validating the initial grouping pattern with a new sample of seafarers (n = 35). The result is a pattern to group 48 types of information on shipboard navigation displays into 13 groups. The paper details the selected methods and the findings, and provides implications for future research.

Despite continuous efforts to improve shipping safety, groundings are still the prime cause of large scale oil pollution of the marine environment. As the bridge operator remains the most important part of navigation, the provision of tools which promote his understanding of the threats which lie ahead of the ship has become a permanent challenge. In this work, the use of a hull-mounted forward-looking sonar as a navigational aid for grounding avoidance and ultimately as an associated oil-spill risk control option for oil tankers is examined according to the Formal Safety Assessment (FSA) approach. In this context, the sonar's oil-spill risk reduction potential and its overall cost were estimated and assessed against the Cost of Averting a Ton of oil Spilled (CATS) criterion. It was found that the currently available sonar technology has a maximum detection range which is adequate for the avoidance of powered groundings in the case of small-sized oil tankers only. However, for this ship size category, the attained oil-spill risk reduction was found to be low and sonar use was proved to be cost ineffective. However, it was found that sonar technology will offer sizable oil-spill risk reduction in large-sized oil tankers and their requirement for longer sonar detection range can be easily met cost-effectively as an oil-spill risk control option for ships of this size.

In many practical situations in the field of navigation, it has been noticed that the probability distribution of measured errors has a shape which has considerable departures from that of the normal distribution. These departures are particularly noticeable in the ‘tails’ of the distribution of practical cases, which are often higher than those of the corresponding normal distributions (see, for example, ‘Is the gaussian distribution normal’, W/Cdr. E. W. Anderson. This Journal, 18, 65).

Passenger and cargo liners sailing on regular routes follow tracks for a given voyage, taking account of the various seasonal conditions which may apply, and masters of these ships, with many years experience in a particular trade, can decide without great difficulty the most advantageous track for their ship when planning a voyage for a given time of year.

In the transport of oil, on the other hand, it is not common to employ ships on regular voyages, and the great majority of tankers are employed in world-wide trading, so that although a particular oil company may have a number of ships constantly voyaging on a particular route, a high degree of flexibility is maintained and ships are regularly changed from one route to another. This means that the tanker master is called upon to consider the requirements for optimum routing of his ship on any ocean voyage. Further, he is often given his orders with fairly short notice and, in some cases, he may have his destination changed either at the last moment or during the voyage, leaving him little time to consider the many factors which have to be taken into account when planning the best route for the voyage to be undertaken.

In all forms of navigation a distinction can be made between the two processes of finding out what the present position is and finding out what direction to go in to reach a given destination. On land the former process becomes the more important of the two because the constraints of natural ground features or of artificial obstacles often make a preset course impossible, as a motor drive along English country lanes shows so well. The destination will often be reached from an entirely unforeseen direction.

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.

The establishment of standards for lateral separation between adjacent jet routes depends in large part on an adequate description of aircraft path-keeping ability. While it has been accepted for many years that deviations from route centreline follow a distribution which is more peaked in the core and longer tailed than the gaussian distribution which was initially assumed, the selection of an alternative distribution is still moot. Early studies of oceanic data suggested that a double exponential distribution gave a much better description of the core data. However, this distribution still appeared to underestimate the frequency of occurrence of very large errors, so that a double-double exponential distribution was proposed and is currently used for establishment of MNPS (Minimum Navigational Performance Specification) criteria for the North Atlantic organized track system. A physical rationale for the occurrence of the double-double exponential distribution has recently been derived, with suggestions for consideration of alternative formulations.

This paper, by the Deputy Operations Manager of the Marine Department of Hunting Surveys Limited, was presented on 15 November 1979 at a meeting of the Solent Branch of the Institute held at the College of Nautical Studies, Warsash. It deals with the operation of semi-submersible laybarges based on experience in the northern North Sea from 1975 to 1979. It covers, from the survey contractor's point of view, the different phases of operation from the time the oil company selects the route until the line is laid and surveyed on the seabed. Some aspects of the work described would not normally be associated with surveying or navigation but have been carried out by survey teams in laybarges.

Over 20 years ago, collision with high ground was identified as being the single most significant cause of fatalities among air travellers worldwide (Smith, 1968), and some human factors responsible were highlighted. The three factors most commonly found to be present during major civil aviation accidents were: (i) pilot's visual flight in instrument meterological conditions (IMC); (ii) navigational error by the crew and'; (iii) pilot's failure to react correctly to new circumstances resulting from air traffic control (ATC) instructions or advice – sometimes made in a language foreign to that of the aircrew. The latter factor will be tested here to see if it still applies to recent cases in the UK.

Lucretius, in the century before Christ, was by no means the first wise man to ponder and seek to explain the apparent mystery in this biblical citation, and he is but one of a great company of ancients whose recorded sayings are a delight to all who love the sea. We shall come back to Lucretius.

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.

For a long time it has been accepted as fact that at least certain animals, such as birds and honey bees, have an in-built sense of orientation which enables them to find their way home. Less well-known examples occur among the molluscs and amphibians.

This paper was presented at a meeting of the Bristol Channel Branch of the Institute i n Cardiff on 28 April 1976.

The work and life of John Thomas Towson falls neatly within the professional group so aptly styled by the late Professor E. G. R. Taylor as the Mathematical Practitioners. Born in Devonport in 1804, Towson was educated at Stoke Classical School in that town and on leaving school followed his father's trade as a chronometer maker. When only 22 years of age Towson invented a device for banking the balance of a chronometer and his invention was communicated to the Society of Arts in 1826.

The voyage of Luis Baez de Torres in 1606 resulted in the discovery of the whole southern coast of New Guinea, and of the existence of a strait between Australia and New Guinea. These great geographical results were hidden from the world, and even from the Spanish realms, so completely that sufficient data on the voyage for general study has not been available until recently. The very brief report by Torres to the King was not found, copied, translated and published until 1806, exactly 200 years after the voyage; the four charts made during the voyage were published in 1878, and the long narrative by Prado was found by chance in London, translated, and published in 1929. Hundreds of documents of secondary importance were collated and published in 1965, but owing to the habit of historical writers of using older ‘authorities’ instead of original sources, many fallacies regarding the voyage have been perpetuated to the present day, and no doubt will be in the future. The present writer, working from photostat copies of the original reports and charts, has plotted the track of Torres' two vessels from island to island and point to point by interpreting the records, by navigational deduction and from a long experience of navigating ships through the very waters traversed by Torres. He has also made sketch surveys of uncharted areas and has studied the various rare charts, maps and globes compiled by different cartographers between 161 3 and 1700 from the three or four coastal charts drawn by Prado but missing from the archives since soon after the voyage.

The principal conclusion of this study is that Torres used Endeavour Strait to get clear of the innumerable islands and reefs which blocked his course to the west and was therefore in sight of the Australian coast for many days, a finding contested by several previous writers.

In a recent issue of Nature Sir Charles Goodeve gave an illuminating account of the value of operational research in war and described how, in peacetime, similar methods were being applied to problems of rail and road traffic. It is significant that he was unable to give examples of similar investigations into the flow of air traffic.

Migratory directions of birds have long been assumed to be at least partly ‘innate’ that is, genetically determined. In recent years much progress has been made toward understanding the genetic basis of several components of the orientation system. An important distinction has to be made between a bird's ‘knowledge’ of which direction to migrate, and its ability to use certain compass systems to find this intended direction. Both processes, establishing an intended direction and the subsequent compass orientation, have a partly genetic basis. The present review will be concerned only with the first of these processes, and the way it allows evolutionary changes of migratory routes to occur.

A new system of electronic scanning is described in which the narrow receiving beam of an acoustic echo-ranging equipment (i.e. asdic) is swept over a wide sector at a very high speed. Since the transmitted pulse covers the whole sector, and the scanning is done at least once per pulse duration, an effectively instantaneous search of the sector is made without any loss of information. The results of trials at sea are shown and possible applications to surveying and navigation are briefly discussed.

The use of underwater acoustic echo-ranging systems in the form of echo-sounders (as fitted on most ships nowadays) and asdics (as used, for example, for submarine detection during the war and now applied to whale-finding and fish-finding) is well-known.1 These existing systems use a single beam of acoustic energy, the pulse being transmitted by a transducer (or loudspeaker), and received, after reflection from the sea-bottom or whale or other object, by the same or a different transducer (this time used as a microphone). The time difference between transmitted and received pulses measures the range of the bottom or object, and is recorded on a chart by a stylus moving at a speed equal to the velocity of sound in water multiplied by the ratio of the width of the chart to twice the maximum range of detection. The transmission of the pulse marks the left-hand edge of the paper, and any echo received causes a mark at a point in the stylus sweep corresponding to the range of the object causing the echo. The paper is meanwhile moving at right angles to the stylus sweep, so that the next pulse transmission marks on a line adjacent to the previous one.