bluuebunny/crossref_metadata_2025 huggingface dataset:
The Mystery of Captain Lane's Compass
Authors: May W. E.
Published: November 2009

Charles Henry Lane was born at Hereford about the year 17J4 and at the age of 17 joined the Buckingham, 70 guns, Captain John Symons. In this ship he went to India, spending about four years in her, the first two as able seaman and the second two as midshipman. Returning home he joined the Enterprize, 28, Captain Sir Thomas Rich, spending about two years in her in the Mediterranean. Of these the first three months were as able seaman and the rest as midshipman.

In July 1777 he successfully passed his examination for lieutenant and in September received his commission to the Royal Oak, 74, initially as 5th lieutenant but rising to 3rd before, in April 1778, he was appointed 1st lieutenant of the Surprize, 28, Captains Robert Linzee and later Samuel Reeve. In that ship he served just over three years, each year making a voyage to Newfoundland and back from about June to November. While in those waters on the third voyage he was transferred to the Portland, 50, Captain James Luttrell. Then in September 1782 Vice-Admiral John Campbell promoted him to Commander and placed him in command of the sloop St Johns, which had been purchased locally. Exactly a year later the St Johns was paid off and Commander Lane returned home and was placed on half-pay.
Simple Sextant Calibration
Authors: Kerst D. W.
Published: November 2009

When the scale readings of a sextant are suspected of error, or if an assurance of scale accuracy is needed, optical equipment for establishing angles is rarely available. Comparison with another sextant is possible, but if the arc between two stars were measured by bringing them into coincidence this could be compared with the calculated angular distance. To calculate the distance from a spherical triangle, knowing the stars' declinations and right ascensions, would be laborious and the refraction corrections would be difficult to apply—as they were in the old lunar distance methods. It is far simpler, in the northern hemisphere, to take Polaris as one of the two stars. If the other is within an hour of its meridian passage, so that the measured arc is approximately vertical, the usual corrections for refraction are sufficient. Also the calculated angular distance will then be simply 90° – δ, where δ is the declination of the star selected. This calculated distance is therefore subject to two corrections:

(i) refraction corrections for both stars,

(ii) a correction for Polaris not being exactly at the pole.
Reporting Near Misses at Sea
Authors: Nicolson D.
Published: November 2009

Not surprisingly much of the work that has been done on collision at sea has involved the study of collisions which have actually occurred. There must however be a wealth of untapped data relating to ‘near misses’ judging by the hair-raising stories often told by ships' officers. These accounts, sometimes of ships passing one another so closely in fog that human sounds have been heard, are doubtless subject to embellishment but are, nevertheless, the stuff that nightmares are made of.

An interesting point which (perhaps predictably) features in many such stories is that the navigator presents himself as a victim of circumstances rather than one who has suffered the effects of a wrong decision. Curiously the ‘other ship’ sometimes shares this diplomatic immunity. Discounting ‘acts of God’ then, is there room for a category of encounter in which blame is minimized or even ruled out? In the discussion following a recent paper Captain F. J. Wylie states that between 1948 and 1966 most of the collisions he had studied which had come to court had, according to the Judge, been due to personal error (generally related to the Rules or misinterpretation of radar information). This no doubt reflects the situation in a true light provided one accepts that it may occasionally be necessary to distinguish between ‘personal error’ and blame. The two might not go together, for example, when the error is due to overloading of the human system or under-exposure to congested waters—a view which appears to be gaining support in some quarters.
Saving Money by Cutting Corners
Authors: Proctor J. D.
Published: November 2009

This note assesses the savings in (time- and fuel-dependent) direct operating costs that are possible if every turning point on an airway is passed on the inside. Figure 1 shows a route with turning points at A, B and C. If a pilot follows the standard procedure of flying along AB until he is sure that he has passed B, his total track distance is (c + d + a + b).

To simplify the mathematics let us assume that he turns instead through half the required angle at a distance d before he reaches B and completes the turn after passing B abeam (and very close). His track distance will be (c + e + f). The difference in distance δ, representing the saving, is therefore (d + a + b) – (e + f).
Matthew Flinders and Ship Magnetism
Authors: Mörzer Bruyns W. F. J.
Published: November 2009

Readers of Captain Cotter's paper under this title in the April 1976 issue of the Journal may be interested in some evidence that Dutch seamen in the seventeenth century were aware of this phenomenon of ship magnetism.

Abraham de Graaf in De seven Boecken van de Groote Zeevaert, published at Amsterdam in 1658, warns ships' officers taking bearings with the compass-that metal objects in their clothing can seriously deflect the compass, and mentions iron buttons and buckles. This was an important contemporary work on navigation and de Graaf was an examiner of officers of the Dutch East Indies Company from 1679 to 1714.
GPS for Aviation
Authors: Ratcliffe S.
Published: November 2009

It must be stated at the outset that the present author has a technical knowledge of Navstar GPS based only on fragments of the literature open to the public, and no knowledge whatever about the plans for its military use. An attempt will be made to discuss, from first principles, the consequences to both civil and friendly military users of the availability of a global, satellite-based navaid that makes possible the determination of position in three dimensions to a high accuracy. For civil users, confined to the ‘coarse acquisition’ mode, there is a 95 per cent probability that the horizontal position error will not exceed about 20 metres. For military users holding the key to a more sophisticated mode of operation, a significantly greater accuracy is available. The GPS also determines velocity, and data can be updated every second or so. It will be assumed that the navaid covers all the Earth's surface of interest, down to ground level. The cost of the satellite system is assumed to be high.
Integrated Navigation Systems for Aircraft
Authors: Stokes R. F. , Smith S. G.
Published: November 2009

Work on integrated navigation for aircraft started at RAF Farnborough at least as early as the mid 1950s. At that time the Inertial Navigator (IN) for a guided bomb was being developed and the navigation of the aircraft to the target used a combination of the weapon IN, Doppler radar and position fixing. An output of the navigation process was a calibration of the weapon IN. The operational concept was interesting in that after weapon release the aircraft had to return home using Doppler and compass.

Development of this system included flight trials in raf and a & aee aircraft using the Decca Navigator chains in Southern England for position reference. The same method was used in the development of the FSP 100 IN intended for the TSR 2 which took place in 1960/63. On these trials an early airborne digital computer on board the trials aircraft enabled Decca, Doppler and the IN information to be recorded and processed in-flight in a form suitable for post-flight analysis using a ground digital computer. This technique formed the basis for producing the reference navigation system which has been used for all our subsequent trials. The production of a position, velocity and attitude reference system for trials of inertial and other navigation systems has formed a major objective for RAE work on integrated navigation since that time.
New Display Systems for the Next Generation of Civil Aircraft
Authors: Bernard Maurice
Published: November 2009

The history of aeronautics has been marked by a number of revolutionary breakthroughs influencing both designers and users. A major example is the advent of jet aircraft. In flight deck instrumentation the technical revolution has followed a steadier course, enabling a gradual evolution from the rudimentary instruments used on yesterday's aircraft to the sophisticated instruments used today.

In this respect, the information displayed has evolved both in quantity and quality. This has gradually led to new flight deck designs such as that used in the Airbus A 300. The impression of a gradual evolution in instrument technology is due to the fact that information is often displayed in the same manner as before, i.e. using dial indicators. Today, a new revolution is taking place in commercial aircraft flight decks: the use of digital systems displaying processed data on cathode ray tube (CRT) displays.

Preliminary Studies. The use of CRT in flight deck instrumentation has been under study for a number of years. Many aircraft are already fitted with CRT for specific applications such as weather radar information and computer-processed data (on display units linked with computers).

The present CRT breakthrough is tending to compete with or replace conventional instruments. This tendency started in 1968–70, giving rise to a number of preliminary studies, with military aviation quickly taking the lead. Studies were also carried out in commercial aviation, for example those of the Boeing SST programme which, as is commonly known, was later cancelled.
Collision Threat Parameters for a new Radar Display and Plot Technique
Authors: Lenart Andrzej S.
Published: November 2009

The paper, an edited and shortened version of the original, discusses a new approach to the display of collision threat parameter areas, obtained as a result of theoretical considerations. It can be applied to radar-computer anti-collision systems as well as manual radar plots.

With the development of digital techniques, and electronic digital computers in particular, radar-computer anti-collision systems are now aboard ships. Digital processing of signals and data in such systems can be divided into three stages as follows:

(a) Primary processing, which includes an analysis of radar signals within one rotation of the radar antenna. A result of this processing would be the position coordinates of detected objects. For relatively simple algorithms and high speed of analysis, special devices are usually employed.

(b) A secondary processing, which includes a correlation of the information obtained in the primary processing stage; the objects' position coordinates in consecutive antenna rotations; and an estimate of position, motion and approach parameters. For secondary processing devices general-purpose mini- and microcomputers are usually applied.

(c) A graphical display of the calculation.
Collision Avoidance from the Shore
Authors: Degré Thomas , Lefèvre Xavier
Published: November 2009

French maritime surveillance centres have been operating for several years. Experience gained over this period, and the French government's desire to take all steps to limit the possibility of catastrophic pollution, has led the French lighthouse and navigation service, in cooperation with the transport research institute, to implement an updated programme for maritime surveillance centres to allow them to carry out their existing tasks more efficiently and increase the scale of their activities. For this reason, a new system is being tried out at Gris-Nez Centre. It comprises a computer, which receives radar data from the radar tracking computer and effects partial automatization of the operator's tasks. In the future, it is hoped to use this new computer to help the operation centre detect the most dangerous encounter situations between vessels.

Obviously the centre is not intended to replace the officer of the watch, who will retain full responsibility, but it can assist by putting him in touch with vessels which he could encounter. A typical case where the centre might help is that of a vessel whose radar is out of service, or a vessel hindered by her deep draught and limited manoeuvrability.

The participation of such centres in preventing collisions is a new factor in maritime operations and can only be introduced when all preliminary investigations have been carried out.
Quantitative Measurements of Navigational Safety
Authors: Goodwin E. M. , Lamb W. G. P. , Kemp J. F.
Published: November 2009

In recent years it is probably true to say that the main pressures for inprovements in navigational safety have come from public and hence political sources. The pressure has usually taken the form of proposals for increased regulation of marine traffic. Often there is a defensive reaction from the professional mariner on the grounds that there is no real evidence that the proposals will produce a significant improvement in safety. Shipowners are also worried because of potential increased costs and curtailment of operating freedom.

It is therefore important that more information is made available so that both the safety aspects and economic aspects of additional regulation may be assessed. This paper is an account of a study into the development of danger criteria for marine traffic flows. This study was the key part of a larger one which was funded by the Department of Industry through its Ship and Marine Technology Requirements Board, now superseded by the Marine Technology Committee.

Collision rates on their own are usually not suitable for measuring safety risk, as collisions in a specific area are normally a very rare event. It is also not advisable to use data collected over several years as the traffic is likely to change, e.g. size of ship. Another approach might be the reporting of near misses, but there are considerable problems if navigators are asked to do this especially as there might be subjective judgments on whether to report an incident or not.
Marine Traffic Behaviour in Restricted Waters
Authors: Coldwell T. G.
Published: November 2009

This paper, which was presented at an Ordinary Meeting of the Institute held in London on 26 January 1983, outlines the development and analysis of the ship domain in restricted waters and illustrates some of its uses in a buoyed channel.

The analysis of marine casualties raises the question of how casualties occur, and may indicate the circumstances most likely to lead to a casualty. In addition, information may be gained as a basis for estimating the risk of a casualty and for assessing the effectiveness of proposals for improving the safety and efficiency of navigation in the area.

The use of casualty statistics as a measure of marine risk has distinct limitations. In most areas a casualty is a reasonably rare occurrence, so that any systematic analysis of casualties will normally have to take place over a period of a few years; and, if improvements are made, a further period of time is necessary to measure their effectiveness.
Defining the Close-Quarters Situation at Sea
Authors: Hilgert Helmut
Published: November 2009

The International Regulations for Preventing Collisions at Sea contain several important terms which are open to different interpretations such as ‘safe speed’, ‘close-quarters situation’ and ‘risk of collision’. It is not possible to give exact definitions of these terms as some of the factors involved are difficult to quantify but there is little doubt that mariners would welcome some official guidance on their application.

The following paper by Dr Hilgert proposes a method of defining ‘close-quarters situation’ in terms of the principal factors which apply. The method is of particular interest because it is actually used by the maritime administration of one government and has been submitted to the International Maritime Organization for consideration. The IMO Sub-Committee on Safety of Navigation has taken note of the suggested approach and has invited comments.

It is suggested in the paper that a simplified version of close-quarters situation could be determined in terms of the quantifiable parameters of speed, manoeuvrability and angle of approach. The method could be used to establish minimum values of a close-quarters situation but other factors would have to be taken into account such as the close presence of navigational hazards or other vessels, radar performance including the effect of errors and the desirability of keeping out of audible range of the fog signals of an approaching vessel.

Despite some obvious limitations the method serves to indicate the least values which should be used and the paper contributes to a better understanding of this aspect of the avoidance of collision at sea.
Nautical Chart Standardization
Authors: Newson D. W.
Published: November 2009

This paper deals with the work of the International Hydrographic Organisation (IHO) during the last ten years towards the standardization of nautical charts. The work began with the devising of a regional scheme of medium- and large-scale sheets of the north-east Atlantic area, to be co-produced by member nations as contributions to an International (INT) set of charts. It subsequently became clear that, as well as the scheme, a detailed set of specifications would be necessary to secure uniformity of choice of symbols and abbreviations throughout the International series, and also in the various national chart series of which it would form a part.

The history of nautical chart standardization has recently been traced by Ritchie – gradual at first after the beginning of the International Hydrographic Bureau in 1921, and later speeding up when the International Hydrographic Conference of 1967 established a study which led to two series of INT charts on very small scales. After this the process gathered further speed with the successful establishment of the two bodies with whose work this paper is primarily concerned: the North Sea International Chart Commission (NSICC) in 1972 and the Chart Specifications (later Standardization) Committee (CSC) in 1977. The ten-nation NSICC, in drawing up the network of INT sheet-lines for its area, established the principles on which such schemes would be extended worldwide and also did extensive groundwork for the Chart Specifications of the IHO. These were completed for worldwide application by the seventeen-nation CSC.
Ship-based Weather Routing Using Dynamical Meteorology
Authors: Motte R.
Published: November 2009

Many vessels trading on North Atlantic routes are equipped with weather facsimile receiving devices of various types. Ship-masters engaged on regular voyages in this area are thus able to conduct their own passage planning using the information readily available from these intruments. The capital cost in relation to other ship operation costs is negligible; in US dollars (1983) it is likely to be of the order:

There would be no problem in planning a vessel's route across an ocean if it were possible to forecast with total accuracy the actual sea state existing for the duration of a voyage. Such an ideal circumstance does not yet exist and a method must thus be used which incorporates flexibility to modify a voyage plan as actual weather varies from the prognosis. This means that a subjective approach to storm avoidance may, on occasions, be preferable to the stringent demands of a least-time track. The obsession of routing agencies with the latter method may be one reason why weather routing has not achieved the success it perhaps deserves.

A ship may be damaged or delayed by the action of sea waves on her hull or structure. Hull form and ship dimensions are usually selected on the basis of calm-water performance, rather than for sustained sea-speed.
In a Flat Spin
Authors: Williams J. E. D.
Published: November 2009

An announcement of Wing Commander Anderson's recent death appears on another page. Mr William's spirited criticism of Anderson's ‘Rotations in Navigation’, and by implication his more recent note on Coriolis (May 1983 issue), was of course written before the sad news was known. It is published here without modification (and in spite of the author's offer to withdraw it) as would undoubtedly have been Wing Commander Anderson's wish.

At the end of the last war Wing Commander E. W. Anderson was one of the most distinguished practising navigators in the Royal Air Force. ‘Andy’, as he is known to so many, has since become navigation's leading exegete through his work in this Institute, his articles, lectures and books. ‘Rotations in Navigation’, however, has got him in a flat spin. The reason why has wider implications worth examining.

Andy starts by suggesting that the difficulty of explaining Coriolis ‘may be due to the intellectual danger of trusting mathematics without making sure that the right circumstances surround the formulae which emerge’. This observation illustrates how well one can write English without saying what one means. Circumstances, right or wrong, cannot surround a formula although the statement a formula makes may be irrelevant to our circumstances. It is precisely because pure mathematics is the language, as Russell put it, ‘in which we do not know what we are talking about or care whether what we say about it is true’, that applied mathematics is the language in which we are obliged to say what we mean or be seen to use the language wrongly.
‘What Course Should You Steer?’
Authors: Muir Langley R.
Published: November 2009

Van de Ree has provided a solution to what must be a fairly common problem in navigation. The problem may be stated as follows.

A ship on a rhumb-line course encounters head-winds and heavy seas requiring her to reduce speed. If she alters course, but does not change the rate of fuel consumption, her speed will be given by (a + b sin A), where A is the course change, a is the speed into the head sea and a + b is the speed in a beam sea. How far should the navigator alter course so that, after a given time, the ship will be nearer the destination than on any other course and, in addition, the labouring of the vessel will be reduced?

Van de Ree's trial-and-error solution assumed the destination to be initially 63 miles away, a = 12, b = 5, and the optimization period 1 hour. His solution was to alter course by 20(± 2·5)°. It is possible to obtain a general algebraic solution to this problem, but it requires differentiating complicated trigonometric functions and solving a complicated trigonometric equation, and so the algebraic solution is not practically useful. It is also possible to solve the problem graphically. This solution is by far the simplest one and would be recommended in place of either Van de Ree's laborious numerical solution, or the equally difficult algebraic solution.

However, one could question whether the chosen tactic is the appropriate one.
Statistics of Ship Collisions
Authors: Cockcroft A. N.
Published: November 2009

FOR traffic proceeding in random directions on a plane surface the frequency of collisions, if no avoiding action is taken, is approximately proportional to the square of the traffic density and directly proportional to the size and speed of the craft. Avoiding action is normally taken and the rate of collisions is therefore also governed by additional factors such as the visibility, the effectiveness of the collision-avoidance rules, the competence of personnel, the manoeuvrability of the craft and the efficiency of radar and other equipment.

In the post-war years there has been a considerable increase in the number of merchant ships. The number of vessels of ioo tons gross and upwards increased from less than 30,000 in 1948 to over 65,000 in 1976. When considering the population of ships at risk it is necessary to deduct special types of non-trading vessels and ships laid up. The number of trading ships in service has increased by approximately 100 per cent since 1950 (Fig. 1) and the greatest increase has been for large ships. The average length of trading ships has increased by approximately 40 per cent in the same period and there has also been an appreciable increase in the mean speed of ships.
Increasing the Shipping Capacity of the Suez Canal
Authors: Griffiths J. D. , Hassan E. M.
Published: November 2009

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.
‘The First Navigation of Torres Strait’
Authors: Ingleton Geoffrey C.
Published: November 2009

Captain Brett Hilder first published in 1973 his controversial theory that Torres used Endeavour Strait on his famous and perilous voyage through the intricate waters of the strait that now bears his name. This was the subject of his Macquarie University thesis of 1976, The voyage of Torres along the southern coast of New Guinea in 1606 and he has summarised his findings in a paper published in the September 1977 issue of this Journal. It now seems essential to question the validity of some of his assertions.
SST Flight Planning and Navigation: the first year's experience
Authors: Guest T. C. R.
Published: November 2009

Concorde has now been operating on routes both east and west of Europe for over a year and has become an accepted part of the international air transport scene. This paper examines these operations in the light of experience, with emphasis on navigation and operational planning. Of special interest is the way in which the triple inertial navigation system on the aircraft has been used to ensure accurate and reliable track keeping on complex routes. Concorde routes are constrained as much by political as by operational considerations and long term planning was necessary to obtain route profiles which gave the shortest distances and optimum acceleration/deceleration points.
New Studies in Collision Avoidance Radars
Authors: Butt J. A. , Jones K. D. , Rowsell C. G.
Published: November 2009

Collision avoidance radars formed the subject of an Institute meeting held in London in October 1975 (this Journal, 29, 232). The subject has been given a sharper edge by President Carter's message to the U.S. Congress on 18 March 1977 which proposed, amongst other regulations, that all oil tankers over 20,000 dead weight tons which call at American ports, should carry ‘back-up radar systems including collision avoidance equipment’. The issues are highly contentious and the Institute has published a great deal on either side as the debate has grown. The papers which follow describe a research project carried out at the Department of Maritime Studies at Liverpool Polytechnic for Shell International Marine. They were presented at an Institute meeting held at Shell Centre on 17 November 1977 with Captain Ralph Maybourn in the Chair.

J. A. Butt, Head of the Communications and Navigation Department at Shell International Marine, first looks at the investigation from the shipowner's point of view. Captain K. D. Jones, an Extra Master, and Director of Research in Maritime Studies at Liverpool Polytechnic, then discusses the scope of the project and describes the range of experience undertaken. C. G. Rowsell, seconded from Shell Tankers U.K. Fleet to the Operational Services Department, Shell International Marine, finally, gives a detailed account of the investigation and its results. The discussion was opened by Captain A. Wepster, Director, Navigation Research Centre, Netherlands Maritime Institute, and Captain F. J. Wylie, provides a written commentary.
Problems of Navigation in High Density Traffic
Authors: Le Pla P.
Published: November 2009

The number of ships in the world's fleet increases each year, and at an increasing rate. In 1975, 2530 new steam and motor ships went to sea, compared with 1006 in 1965 and 134 in 1955. The tonnage increase is even more startling. Lloyd's Register of Shipping quotes the 1975 total world tonnage of vessels of 100 gross tons and upwards as 342,162,000 tons, an increase of about 10 per cent over the previous year and double the figure recorded in 1966. These larger ships are less manoeuvrable and more difficult to stop. They are also restricted in where they can go in safety and thus constitute a considerable collision and stranding hazard. The growth is most apparent in tankers, ore carriers and OBOs (oil, bulk or ore carriers). The French Shell tanker Batilus (550,000 tons) quoted as having a 72 ft draught is operating close to home and recently discharged 170,000 tons of crude oil at le Havre before continuing her passage to Rotterdam. In January 1977 the Chairman of Globtik Tankers ordered three nuclear powered oil tankers for delivery in 1985, 1986 and 1987. Their size is quoted as 600,000 tons, and their speed as well over 20 knots. The Globtik Tokyo is already at sea—469,470 tons deadweight, 1243 feet long, 203 feet beam and 92 ft draught! She sails under the British flag, and trades between Japan and the Persian Gulf. The U.K. has now nine ships of over 140,000 tons gross (275,000 tons deadweight) out of a world total of 59 and the world total of ships over 100,000 tons gross was 479 at the last count.
Crossing Traffic Separation Schemes
Authors: Glas K. , Paton J.
Published: November 2009

Ample information is available on the growth-process of the International Regulations for Preventing Collisions at Sea 1972. However, after having been set to words little has been published in the Netherlands to assist the ‘men on the bridge’ in the practical use of these Rules of the Road. In the Netherlands—as elsewhere—seafarers have attended courses which dealt with the use and interpretation ol the revised Rules. Little is known of deliberations and consultations between national and international Institutions and consequently it must be feared that mariners have not been uniformly advised.
The Probability of Close Overtaking in Fog
Authors: Curtis R. G.
Published: November 2009

In areas of high marine traffic density it has been necessary for IMCO to introduce traffic separation schemes to reduce the total number of encounters, and in particular the dangerous head-on encounters. It is now widely acknowledged that separation schemes can and do improve safety. However, as a side effect they unfortunately increase the number of overtaking encounters. For example the introduction of a separation scheme in the Dover Strait (with 1 per cent of ‘through rogues’) has increased threefold the proportion of potential overtaking encounters.
Collision Avoidance as Observed by Shore Based Radar
Authors: Barratt M. J.
Published: November 2009

Of all forms of transport, ships are unique when it comes to avoiding one another. Compared with both land vehicles and aircraft they have remarkable freedom of action, so that collisions are avoided less by external regulation than by mariners exercising their individual skill. A framework for their actions is provided by the collision regulations which have evolved over hundreds of years, a process which seems unlikely to reach an end in the near future. Since it is reasonable that any changes should be informed by events, information on what mariners actually do to avoid one another can only contribute to the safety of ships at sea.

This paper is concerned with obtaining information on collision avoidance from radar records. It describes the data extraction and the selection of encounters between vessels, and presents some sample statistical results. Finally, probable applications of the information are discussed.
A Mid-Channel Survey of Vessels Routed Past Ushant and Cherbourg
Authors: Chalk R. F. , Coupard A.
Published: November 2009

The memory of the Amoco Cadiz disaster of 1978 is still fresh in the minds of most people. The loaded VLCC drifted on to rocks 3 miles off l'Abervrach and caused almost a quarter of a million tons of crude oil to engulf the Brittany coast. Almost immediately some far-reaching measures were put into effect by the French authorities through IMCO to lessen the likelihood of a similar incident occurring again. Perhaps the most important of these were the fundamental alterations which were made to the traffic separation schemes off Ushant and the Casquets to route the large oil carriers well away from the French coast.
The Visual Estimation of Miss Distances at Sea
Authors: Lamb W. G. P.
Published: November 2009

It is usually accepted that the visual estimation of miss distances at sea is difficult and that it is advisable to employ plotting methods with visual observations (or radar echoes) to assess the positions and movements of neighbouring vessels. Nevertheless, direct visual assessment is likely to remain a useful adjunct to more sophisticated methods, at least under conditions of good visibility, particularly as the use of radar does not absolve the mariner from keeping a good look-out at all times. It seemed, therefore, useful to examine some of the factors involved in the visual estimation of miss distance, in the hope that such an analysis might suggest ways in which the direct assessment of close-quarters situations could be improved.
Ship Traffic Through Gibraltar Strait
Authors: Mavor James W.
Published: November 2009

A recent oceanographic cruise of the Spanish research vessel, B. O. Cornide de Saavedra, provided a suitable platform from which to survey ship traffic through the strait of Gibraltar covering several days. This was long enough for a representative sample to be taken, 472 ships. It was observed that only 65 per cent of the ships passing through the strait observed the traffic lanes. The current structure of the Alboran Sea may offer economic advantage to a different traffic convention. The present mean traffic is 5·8 ships per hour which represents a density greater than that of the Strait of Dover. This suggests that traffic regulation, in the interests of preventing loss of life and oil spills, may be necessary in the near future, particularly when the Suez Canal has been opened to larger tankers.
A Direction-Cosine Position Coordinate System for Air Navigation
Authors: Morleigh S.
Published: November 2009

For short range air navigation the most general method of determining the distance between two points, and the course to be steered from one to the other, is by means of a grid system of coordinates based upon some map projection. Problems must arise, however, in routing aircraft between Traffic Control centres in adjacent regions which employ different grid reference systems, even though the airway markers are identified by their latitude and longitude. A difficulty which may result in steering-angle errors arises when these markers, which are generally VOR stations, are referenced to the local magnetic field rather than the geographic pole.
The Magic of Animal Navigation
Authors: Anderson E. W.
Published: November 2009

Animal navigation is magic. Nobody really knows how they do it. We can only suggest the senses they must be using, but how their brains convert this information into action is a mystery. In their heads are computers infinitely smaller, lighter and more flexible than the fantastic silicon chips that clumsy humans employ. Let us first consider what animals have to measure and, to make sure we cover the whole field, we shall look first at what giant tankers, nuclear submarines, Concordes and Apollo space-craft require. [Wing Commander Anderson's article was presented at the Young Navigators’ Meeting in London on 18 December 1979.]
Further Analyses of Position Errors in Navigation
Authors: Hsu D. A.
Published: November 2009

In a recent paper the author reported a distribution theory which rationalizes some fairly well established phenomena in navigational errors. Adequacy of the implied model and other existing models was investigated in the light of empirical evidence. A summary of the findings has been available in a previous issue of this Journal.

This paper provides further insights into several theoretical models, establishes formal procedures for the estimation of parameters crucial to the evaluation and design of navigational systems and investigates the potentials of a broader system of distribution models. In addition, some simplified results aiming at practical use for navigators and air traffic control authorities are provided. A real-world application of the suggested methods and theoretical results is also demonstrated.
An Automated Conflict-alert Function for an Air Traffic Control System
Authors: Bertolazzi P. , Lucertini M.
Published: November 2009

The major purpose of an air traffic control system is to ensure the separation of two or more aircraft flying in the same airspace, with an efficiency that can be expressed in terms of capacity and cost. As air traffic grows in numbers it becomes necessary to reduce the workload of the controllers by relieving them of many monitoring tasks, and eventually some decision-making tasks, through computerized automation. In this context many developments tend to build up an efficient conflict-alert subsystem.

The problem of conflict-alert in the air needs strategic tools, to make collision unlikely or even impossible, and tactical tools to detect impending collisions. The latter detect potentially hazardous aircraft encounters and alert the controller in time to warn the pilots (if necessary) and should obviously provide this capability with a minimal number of false alarms and no increase in workload.
Modern Doppler Navigation Systems
Authors: Gray T. , Thorne T. G.
Published: November 2009

This paper, which was presented at an Ordinary Meeting of the Institute in London on 21 November 1979, with S. Ratcliffe in the Chair, traces the evolution of airborne doppler navigation systems over the past two decades and discusses the treatment of errors introduced when flying over water. Both authors are with Decca Radar Ltd.

The object of this paper is to describe briefly the major developments which have taken place in doppler navigation systems during the past 15 years or so, to indicate the current state of the art and to examine in some detail the behaviour of doppler systems when flying over water. The year 1960 is taken as a starting point since by that time commercial doppler systems were established. A typical general purpose system of that generation (Fig. 1) consisted of the following units:

1. An antenna, probably mechanically stabilized.

2. A transmitter/receiver using either pulse or FMCW modulation.

3. A tracking system.

4. An analog computer.

5. A display of ground-speed and drift-angle.

6. A display of present position.
John Flamsteed and The Origins of the Greenwich Astronomical Tradition
Authors: Forbes Eric G.
Published: November 2009

The work of the Greenwich Observatory throughout the three centuries of its existence has been characterized by the painstaking efforts of its eminent directors to attain an ever-increasing degree of precision in pinpointing the positions of the heavenly bodies, with a view to the improvement of the science of navigation. The pursuit of this purpose, in accordance with the express desire of its founder King Charles II, has been assisted by the steady improvement in the accuracy of the instruments with which it has been equipped, and these have naturally also been applied to investigating problems of a purely theoretical nature. Nevertheless, the tradition pioneered by the first Astronomical Observator (or Astronomer Royal) John Flamsteed (1646–1719) whom the King in 1675 charged with rectifying the coordinates and motions of the heavenly bodies, has remained predominantly practical and utilitarian.
The Cost-Effectiveness of Inertial Navigation for Civil Aircraft
Authors: Edwards A. A.
Published: November 2009

Inertial navigation has been in airline use for some five years and a substantial amount of experience has been built up. The system seems to have fulfilled the expectations of operators. In this paper, which was read at a meeting of the Institute in London on 8 January 1974 with the President in the Chair, Mr. Edwards of British Airways discusses its accuracy and the cost of ownership.

In 1969 a paper was presented to this Institute by F. J. Sullings of the then B.O.A.C. which described some of the engineering aspects of INS and predicted in some detail the costs of operating such equipment for a fleet of twelve B747 aircraft. It is the purpose of this paper to refer back to those early predictions and to make comparison with what has actually been realized. Sullings also referred to the anticipated navigational accuracy of the equipment and this paper will demonstrate that the anticipated accuracies have consistently been exceeded since the first use of the equipment by B.O.A.C. in May 1970. Finally, since the equipment has now been in use for five years, it is considered appropriate to review some developments in which airlines are taking an active interest.
Future Trends in Flight Control Systems
Authors: Hunt G. H.
Published: November 2009

This paper was presented at a joint meeting of the Institute with the Institution of Electronic and Radio Engineers in London on 15 January 1975. The theme of the meeting at which six papers were discussed (a selection of which will be published in the Journal) was Advances in Airborne Equipment for Navigation and Freight Control.

Modern data processors because of their increasing power and flexibility are increasingly used for a variety of functions in modern aircraft, both civil and military. It might seem that a flight control system could be designed of the form shown in Fig. 1, with a powerful central processor taking in signals from all the relevant sensors, gyros, pressure sensors, radar, &c., and operating the control surfaces so as to drive the aircraft along any desired course. But such a system would be quite inadequate in two vitally important aspects: there is no facility for inputs from the aircrew and no account has been taken of failure cases. These and other factors drive the control system designer inexorably towards a total system structure very similar to the type currently used in operational aircraft. There are of course a wide variety of such systems, but most of them are characterized by a number of common features.
The Transformation of Hyperbolic to Geographical Coordinates by a Gradient Method
Authors: Nastro Vincenzo
Published: November 2009

Position fixing with the Omega hyperbolic navigation system requires the use of charts or tables unless the receiver itself is able to display the geographical coordinates directly. Plotting position lines on Omega charts is a simple operation but owing to their small scale (1 : 2, 187, 400 for the Mediterranean area) it is impossible to obtain a satisfactory accuracy of fix, while the use of Omega tables becomes particularly laborious when frequent fixes are required.
Alone to Antarctica in Ice Bird
Authors: Lewis David
Published: November 2009

In 1974 Dr. David Lewis was awarded the Institute's Gold Medal for his work on indigenous navigation methods in the Pacific, and his many remarkable feats of practical navigation. The following account is of perhaps the most remarkable of his voyages which was an attempt to circumnavigate the Antarctic Continent on his own. The first part of the voyage, which culminated in January 1973, was mentioned in the formal citation for the award; the second part, which is every bit as remarkable, finished in Capetown in March 1974.

No one had ever sailed single-handed through the Southern Ocean to any part of the Antarctic continent, not even by way of Drake Passage from Tierra del Fuego, which involves a crossing of only about 400 miles of open sea. Since the sole practicable Antarctic landfall for a small vessel is the Antarctic Peninsula (formerly Graham Land) below Cape Horn, Australia, some 6000 miles to the west, was a far from ideal starting point. However, this was where I was working so that there was no alternative but to make Sydney the point of departure.
A Statistical Study of Ship Domains
Authors: Goodwin Elisabeth M.
Published: November 2009

A ship domain may be thought of as the sea around his ship which the navigator would like to keep free, with respect to other ships and fixed objects. In this paper, which was read at an Institute meeting in London on 12 February 1975 with Captain R. Mayboum in the Chair, Mrs. Goodwin describes studies to determine the dimensions of a domain based on radar simulator performance and traffic surveys in the North Sea. She also suggests applications of this domain concept to marine traffic engineering problems and to traffic control schemes.

In recent years there has been an increasing interest in the sea for it is to the world a means of communication, a source of food and a source of minerals.
Marine Radar Automatic Plotter Display Philosophy—II
Authors: Wylie F. J.
Published: November 2009

The writer's previous article on this subject endeavoured to show that two differing plotting philosophies were currently being offered, one in which the predicted future positions of targets were correlated in time, and the other which displayed unrelated areas in which own ship could come into close quarters with target vessels.
The Use of Ship Manœuvre Simulators
Authors: Ivergård Toni B. K.
Published: November 2009

It is becoming common for ship's officers and pilots to attend special simulator courses to learn the handling of new ships or the navigation of particular channels. A simulator can be defined as any likeness of an object or objects, thus a simple drawing of a ship's bridge is a form of simulation, as is a function diagram or a small-scale model; full-scale models or ‘mock-ups’ are more advanced types of simulator. However a simulator is more commonly taken to be a more complicated set of full-scale models in combination with small-scale models, which usually have the ability to respond to different manœuvring actions with changes in the instruments or the surroundings.
A Nocturnal
Authors: Webster M. W. G.
Published: November 2009

Investigation into the design and accuracy of old-time instruments is always of interest. The Nocturnal probably used from the sixteenth century onwards for estimating the approximate local time at night is well known; with this primitive instrument the Pole Star was viewed through a central hole in a pair of wooden or brass discs. A pivoted arm turned to coincide with the ‘Guards’ of the Lesser Bear, the local time being deduced from an engraved scale. A seventeenthcentury improvement included an extra scale for determining the time by aligning the pointer with the Great Bear ‘Pointers’.