bluuebunny/crossref_metadata_2025 huggingface dataset:
A Computer Simulation of Marine Traffic Using Domains and Arenas
Authors: Davis P. V. , Dove M. J. , Stockel C. T.
Published: November 2009

This paper outlines the concept of a domain and an evasion area, called an arena, around a ship which are then applied to produce a computer model of ship behaviour. The arena determines when a ship takes avoiding action, as does the land arena which reacts with a discrete series of coastal points to prevent the ship running aground.

The increase in the number and size of ships has resulted in the introduction of traffic routing schemes and the need to understand ship behaviour more thoroughly. The concept of ‘the effective area around a ship which a navigator would like to keep clear with respect to other ships and stationary objects’ has been used by various authors including Goodwin, Fujii and Lewison with varying names such as domain, collision diameters and encounter area. There has been no fixed shape for these areas. Some are circular, others elliptical, while Goodwin's has three segments each with its own portion of a circle. By developing the theory of the domain, it was hoped to be able to produce a model of traffic behaviour which could be used to simulate traffic flows, or specific incidents, in order to study them more fully.
On the 95 per cent Probability Circle of a Vessel's Position-II
Authors: Hiraiwa T.
Published: November 2009

For a circular contour, which is one of the methods for indicating an error boundary, the author has studied the conditions for the probability of a ship's position (fixed by two position lines) lying within a 95 per cent circle by probability integration. In this case, the coefficient in the equation to indicate the radius is a function of an intersecting angle and an accuracy ratio between two position lines. The author has examined several accuracy ratios and applied the system to the error boundary of a ship's position fixed by three equally accurate position lines. However, as interpolation involves both angle of cut and accuracy ratio, the process is somewhat troublesome.

In this paper it is shown that the accuracy contour for a fix is an ellipse, whether the accuracies of the position lines are the same or not, and a method is developed to replace an error ellipse for two position lines of unequal accuracy with an ellipse formed by two equal-accuracy position lines. The method is extended to three position lines of unequal accuracy. It then becomes possible to indicate an error boundary by a 95 per cent probability circle.
The Navigation and Positioning of Pipelaying Barges
Authors: Richardson S. A. J.
Published: November 2009

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.
The Use of Transponders at Sea
Authors: Jones K. D.
Published: November 2009

The two papers which follow (Jones and Ratcliffe) were presented in the course of a seminar sponsored jointly by the Institute with the Nautical Institute and held at the City of London Polytechnic on 13 December 1979. The purpose was to examine the usefulness of transponders for marine purposes. Seven papers were presented and these may be obtained at £7.50 (£5 for Members) from the Nautical Institute.

The term transponder is usually interpreted by practising mariners as the simple inband swept frequency device, called Racon, with which those mariners are most familiar. It is this concept which largely colours the mariner's views on the topic, and is perhaps the reason for the obvious reluctance to accept expanding use of transponders which is apparent in the marine industry. Their personal recollected experiences of the clutter caused by Racon and the possible problems that could result from proliferation of such beacons give justifiable cause for this hesitancy.
An Analysis of the Point of Possible Collision
Authors: Riggs Robert F. , O'Sullivan James P.
Published: November 2009

The shipping industry is faced with unilateral legislation proposed by the United States of America covering navigational equipment and, in the interests of harmonization, IMCO is compiling performance specifications and carriage requirements for navigational equipment including collision avoidance systems; the establishment of type approval procedures can be anticipated. The shipowner has reservations, in respect of the need for adequate training in the use of advanced systems and the risk of navigators placing reliance on such devices as collision avoidance systems when their constant availability cannot be guaranteed.
A Sun-compass for Swinging Ship
Authors: Nagel T. J.
Published: November 2009

A tedious problem which confronts many a yachtsman is determining the deviation of his magnetic compass. He can hardly justify the expensive services of a professional compass adjuster, so this necessary but difficult operation must be carried out by himself. Should he decide to use bearings of shore objects when swinging ship he is faced with the difficulty of observing these bearings on his compass. A small-boat compass is hardly likely to come equipped with azimuth mirror and sight vanes. The alternative equipment for taking the bearings is a pelorus, but the expense of this instrument could hardly be justified for such rare and intermittent use.

The favourite way out of the difficulty appears to be to use a hand bearing compass. This method suffers from two disadvantages in particular:

(i) The hand bearing compass should be situated in precisely the same position as the main compass if it is to reproduce the latter's readings precisely. Not only is this impossible to achieve in practice – the nearest they can be brought together is side by side – but when brought close together their mutual magnetic reaction can produce errors of an unknown amount.

(ii) The use of bearings to shore objects naturally entails being offshore. Stationary small boats are notoriously unstable observation platforms and even a light chop would make it impossible to read the main compass with the accuracy necessary for a good deviation card.
‘Studies of Interaction at Sea’
Authors: Corlett E. C. B.
Published: November 2009

I note with interest Dr Barrass' comment in the January issue of the Forum (33, 139). He deals with three subjects: (i) the ultimate trim of tankers in shallow water; (ii) the question of increasing rpm in interaction situation; and (iii) the final turning diameter in shallow water.

Dr Barrass' curves (p. 140, Fig. 1) are useful approximations to squat and to ship characteristics but cannot be treated as definitive.

Fig. 2 is a particular interpretation of practice and not necessarily universally accepted, particularly in respect of the LCB position. In some recent VLCC work benefits have been obtained by moving the LCB aft in association with a buttock-flow stern. Furthermore, the dependence of block coefficient upon Froude number is not realistic, especially in the finer vessels; it is the prismatic coefficient that is dependent upon Froude number. It cannot be taken, therefore, that absolute curves for these factors exist as inferred from Fig. 2.

Turning to Fig. 1, the curves showing sinkage in confined channels are for the blockage ratio bracketing 0·1–0·3. This is a large range of blockage and as a result the curves can significantly underestimate and overestimate sinkage, depending upon where in this bracket a particular example falls. Similarly, the solid curves show sinkage in open water conditions over depth/draft ratios 1·1 – 1·2. This is quite a large range and a unique curve cannot represent these two values.
The Tercentenary of The Royal Observatory at Greenwich
Authors: Sadler D. H.
Published: November 2009

According to Flamsteed's own account, the Royal Observatory was founded as a direct consequence of the representation in 1674 by a Frenchman, who described himself as Le Sieur de St. Pierre, to the English Court that he had discovered a method of determining longitude at sea ‘from easy celestial observations’, and claimed the appropriate award. The solution to the ‘longitude problem’ was then, as it had been for many years and was to be for a further 90 years, of paramount importance; several countries had offered large prizes for a practical solution, and l'Observatoire de Paris had been founded in 1667, a year after l'Academie Royale. (Observations were systematically made for the purpose of improving the determination of longitude by observation of the satellites of Jupiter; but this method, successful on land, was doomed to failure because of the impracticability of using long-focus telescopes at sea.)
The Dover Strait Information Service
Authors: Emden R. K.
Published: November 2009

Captain Emden of H.M. Coastguard's Dover Strait Operations Centre discusses the problems encountered in setting up the experimental Dover Strait Surveillance Scheme and inaugurating the Information Service. The paper, which was presented at a meeting of the Institute in London on 20 November 1974 with the President, G. E. Beck, in the Chair, describes the service today, the results so far achieved and what it hopes to do in the future. A note on the results of surveillance operation between April 1973 and December 1974 will be found at page 244 of this Journal.
Some Hazards to Submarine Navigation
Authors: Dyer A. G.
Published: November 2009

The submarine operates in three dimensions and whilst it has operating constraints in common with the surface ship it has others peculiar to the added dimension. This paper, which was presented at a meeting of the Institute in London on 18 December 1974 with Captain R. Maybourn in the Chair, discusses these constraints as they affect submarine safety and attempts to identify those which are caused by modern commercial activities. The views expressed are those of the author and should not be taken as a statement of Ministry of Defence policy.
Lights for Landfall
Authors: van Hooff J. F. Drijfhout , Sirks Ir. J. C.
Published: November 2009

This paper deals with the facilities for landlall that can be provided by lighted aids to navigation. The relationship between the navigational errors of ships approaching from the open sea and the performance to be selected for a landfall light is worked out. The probabilities of a successful landfall in various circumstances are then analysed. Finally the limitations of light as the sole aid to navigation in the process of making a landfall are discussed. Rear Admiral van Hooff was for long head of the Netherlands Pilotage and Lighthouse Service; Ir. Sirks is technical director of the Netherlands Lighthouse Service.
Navigation in Offshore Powerboat Racing
Authors: Pike R. D.
Published: November 2009

The size and construction of powerboats are governed by the international U.I.M. which has established classes related to engine size and length. Class I boats, where most of my experience lies, can have a maximum length of 4.5 feet and power is limited to petrol engines of up to 16 litres. The speeds of the fastest boats are in the region of 85 m.p.h. with full fuel on board, increasing to around 90 m.p.h. at the end of the race. Over a ton of aviation spirit is carried as fuel. This speed can only be fully utilized in fairly calm conditions. Trim tabs on the transom and a jack for the stern drive units help the driver to keep the boat on the water.
Patterns in Encounters Between Ships
Authors: Rawlinson P. R. J.
Published: November 2009

I would take issue with Spooner on his article in the April 1974 issue of the Journal. On a clear night, with no navigational hazards, a ship is reported at green 30, three miles! An assessment is made and decision to alter course to starboard is ordered. In this time the approaching vessel has made her own decision and altered course to port. Why therefore is the approaching vessel criticized for a port alteration? in my opinion she, the ‘stand on vessel’, has taken such action as to avoid collision without bringing on a close-quarters situation. On such a clear night the approaching vessel must have been visible for at least ten miles and at that range would have been showing all her lights, a clear case for an alteration to starboard on the part of Spooner's vessel to pass clear of the other vessel port to port. Was a lookout being kept at all?
Navigation and Technology
Authors: McKinlay W. H.
Published: November 2009

Over the past thirty years progress in the technologies associated with navigation has been so rapid as to produce a change in the balance between the art of the navigator and the practice of the technologist. The Royal Institute of Navigation was founded at the beginning of this era and one of its major aims was to provide a forum for discussions between practising navigators, scientists and engineers. Therefore, it seems that a consideration of the technical changes should help the Institute to adapt, much as all our social institutions are adapting, as a result of wider changes brought about by science and technology.
Changing the Admiralty Chart
Authors: Haslam D. W.
Published: November 2009

Presented at a meeting of the Solent Branch of the Institute held, by courtesy of the Director, at the College of Nautical Studies, Warsash, on 21 September 1978.

Put your trust in God and the Admiralty Chart! Every one of nearly four million charts issued each year by the Hydrographic Department is as up to date as possible on the day on which it leaves our premises; nevertheless we are increasingly conscious that far too many of the charts are no longer adequate for the uses to which they are now being put.
A Linguistic Approach to Marine Communication
Authors: Bakr M. A.
Published: November 2009

Numerous collisions over the years have emphasized the need for rapid and efficient ship-to-ship voice communication systems. Such systems, set up to satisfy the demand for more and better channels through which messages can be sent, should guarantee that both sender and receiver come to share the same thoughts and feelings. ‘It can be said that two expressions have the same meaning if their utterance results in the same change of behaviour.’ Recognizing that voice communication systems cannot be effective until all parties speak and understand the same ‘language’, the Maritime Safety Committee of IMCO has developed the Standard Marine Navigational Vocabulary, a significant landmark in the attempt to achieve the maximum safety to navigation and the most appropriate conduct of ships at sea. This paper will concentrate on the objectives of the Vocabulary and will try to ascertain if such objectives have been achieved. The analysis will emphasize the viewpoint of ‘non-English speaking people’ using English ‘for the interchange of intelligence between individuals of all maritime nations’, and will take linguistic considerations into account.
Lane Width in a Harbour Passage
Authors: Iijima Y. , Honda K.
Published: November 2009

In this paper Dr Y. Iijima of the Tokyo University of Mercantile Marine and Professor K. Honda of the Kobe University of Mercantile Marine examine the hydrodynamic and navigational factors that determine the safe width of a channel for vessels of a given size and performance characteristics. The results are compared with the widths of existing channels in Japan and elsewhere.
The Application of Transfer Function Techniques to Modelling Ship Control and Navigation Systems
Authors: Gillman D. K.
Published: November 2009

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.
Studies on Interaction at Sea
Authors: Corlett E. C. B.
Published: November 2009

In this paper, which was presented at an Ordinary Meeting of the Institute held in London on 13 December 1978, Dr Corlett, of Burness, Corlett and Partners, describes some of the effects that hydrodynamic interaction has on shiphandling and safe navigation. He concludes that the whole subject of interaction should nowadays be taught to mariners as part of their normal instruction.
Antarctic Navigation
Authors: Woodfield T.
Published: November 2009

In this paper, which was presented to an Ordinary Meeting of the Institute held in London on 22 November 1978, Captain Woodfield, who was for nineteen years master of Royal Research Ships in support of British Antarctic Survey operations, discusses some of the problems of navigating in this ill-charted and ice-ridden area. The presentation was made jointly with Lieutenant Commander P. Le Pla, formerly Navigating Officer of the Ice Patrol Ship HMS Protector whose paper on Antarctic navigation was published in Vol. 31 of the Journal. The President was in the chair.
Pilot Workload in the Aircraft of the Future
Authors: Caraux Denys , Wanner Jean-Claude
Published: November 2009

In this paper, which was presented at a symposium on electronic aids to air navigation held in Paris in November 1977 (and subsequently published in the Journal of the French Institute of Navigation), the authors first analyse in detail the mental processes of an aircraft pilot and the ergonomic factors that should underlie the design of any flight data display. They then describe a cathode-ray tube display designed for use in civil transport aircraft and the modifications they found desirable in the light of simulator trials.
The Simulation of Crossing Manoeuvres at Sea
Authors: Lamb W. G. P.
Published: November 2009

A recent study by digital computer simulation modelling of traffic interactions in the Dover Strait by Batkin made use of a so-called ‘decision-distance’ criterion for locating the point at which a crossing manoeuvre was to begin. This decision-distance was measured along the course of the vessel involved. The manoeuvring vessel was regarded as making an abrupt change of course, by an angle β to starboard on reaching the decision-distance, it having been ascertained beforehand that, in the absence of a manoeuvre, the vessel having the right of way would infringe the other's domain. Although it seems unlikely that such a simple procedure is used by mariners in practice, it seemed useful to examine the implications of the method in terms of the angles of manoeuvre involved, and to make a comparison with an alternative procedure involving the range between ships.
The Distribution Pattern of Omega Observations
Authors: Swanson E. R.
Published: November 2009

The distribution pattern of navigational errors is inherently an important subject bearing as it does on matters of navigational safety. The work of Hiraiwa on the basic distribution of Omega observations is thus a most welcome addition to the literature. There is, however, a major limitation in the data base used by Hiraiwa which could lead to serious errors in analysis of safety based on his findings.
Aircrew and Automation
Authors: Calvert B. J.
Published: November 2009

On 18 June, 1914 Lawrence, son of Elmer Sperry (founder of the Sperry Gyroscope Company) flew over a crowd assembled at Argenteuil, near Paris (Fig. 1). His aircraft was a Curtiss C2 flying boat and the purpose of the flight was to demonstrate the Sperry Gyroscopic Stabilizer in a competition organized by the Aero Club of France. It was a dramatic demonstration. On the first pass over the crowd Lawrence Sperry stood up and held both hands in the air whilst his mechanic, Emile Cachin, walked out on the wing and stood holding one of the struts. The lateral stability of the aeroplane was undisturbed, but the spectators were able to see the ailerons move to compensate for the engineer's weight. This performance was repeated several times and Sperry also demonstrated the automatic ‘volplaning’ function of the system which caused the aircraft to dive and regain speed in the event of an approach to the stall. The company was awarded a prize of 50000 francs as winner of the competition.
Navigation Chart Design
Authors: Kerr Adam J.
Published: November 2009

During the XIIth International Hydrographic Conference, held at Monaco in 1982, Anderson and this writer discussed Communication of the Nautical Chart. In that paper they traced the historical development of the nautical chart, noting how it had evolved and that features of the chart today had resulted more by evolution than by actual design. They noted, for instance, that although present-day charts are often produced by computer and make limited use of colour, they are not significantly different from charts produced some two hundred years ago. Computer methods have been used primarily to copy the work that was carried out so skilfully by the draughtsmen of earlier years. The authors after examining the historical development of the chart then touched lightly on some particular Canadian problems and went on to discuss the first principles of chart design. In particular they suggested that modern cartographic communications research might offer some help in developing the future design of the nautical chart. This paper is therefore a sequel to that work and is directed to presenting some ideas and furthering the discussion.
The Effect of Neglecting the Shape of the Earth on the Accuracy of Sight Reduction
Authors: Bennett G. G.
Published: November 2009

In text books on astro navigation, the fact that the Earth is not spherical in shape is seldom discussed and therefore one presumes it does not have a significant effect on the accuracy of sight reduction, and yet it is quite remarkable that it is not uncommon to find discussions of the phenomenon of augmentation (a correction to the altitude or semi-diameter of the Moon that amounts to about 0·25 at an altitude of 60°) in these books. It will be shown that discrepancies of the same order of magnitude as augmentation may be present in the calculated altitude of the Moon because of neglecting to take into account the shape of the Earth.

In the following (1) rigourous expressions for correcting the observed altitude and geocentric declination of a body close to the Earth are derived, (2) simple expressions which are sufficiently exact for the purpose of sight reduction for the Moon are given, and (3) an example, using different methods of reduction, is shown in detail to illustrate the theory.
Satellite Navigation Systems for the USSR Merchant Marine
Authors: Yakushenkov A.
Published: November 2009

When the satellite era commenced more than a quarter of a century ago, one could hardly foresee the world wide revolution it heralded in the development of aids to navigation for merchant shipping. However, early investigations into the possible application of satellites to maritime needs led to an understanding of the powerful potential of satellite techniques for navigation. It became clear that if the international maritime community was really interested in a global all-weather, high-precision and commercially viable navigation system; such a system could only be satellite-based. This is evident from the situation that has recently arisen in IMO, where after exhaustive discussion on the mandatory carriage of electronic position-fixing equipment on ships in designated areas, the organization could not express a preference for any particular aid, until it was decided that efforts should be made to develop a global satellite navigation system capable of meeting a new standard of navigational accuracy. Moreover, in preparing the navigational accuracy standard, account was taken of experience gained with existing satellite navigation systems.
Position Fixing Requirements for the Merchant Ship
Authors: Ligthart V. H. M. , Wepster A.
Published: November 2009

The subject of this paper is the merchant marine user requirements for position fixing systems (a merchant marine with approximately 40000 ships operating). These requirements are varied and can be summarized as follows:

(i) accuracy

(ii) availability (possible fix frequency)

(iii) reliability

(iv) coverage

(v) user skill and workload

(vi) presentation of information

(vii) ambiguity

(viii) environmental constraints

(ix) operational constraints

(x) system control

(xi) system user costs.

These eleven requirement elements should together serve the two basic purposes of merchant marine navigation: (a) provide a service adequate for safety and (b) enhance economic performance/benefit.
Conclusions of the Conference
Authors: Maybourn R.
Published: November 2009

It is clear that global civil navigation systems have already had a major impact on marine users, and are likely to continue to do so for the future. There is not a marine industry as such in this context, but a number of different classes of marine user, each of which has different requirements, different expectations, and even different viewpoints within a single class. There is even a difference between the viewpoint of what I might call the establishment — governments, IMO and the like — which are concerned with safety, protecting the environment, and such matters, and whose interest embraces a numerical minority of vessels and sea, and vessel operators in general, who represent a potential market of very considerable size and importance. This market, I suspect, will be driven by commercial considerations, and not — at least initially at any rate — by regulation.
The Development of a New Global Atlas of Wave Statistics
Authors: Dacunha N. M. C. , Hogben N.
Published: November 2009

In 1967 a compilation of visual wave data was published as a book with the title Ocean Wave Statistics, which is still widely used. In 1983 work began on the development of a new global atlas of wave statistics which will be available both as a book and as a computer database. This task is being undertaken by NMI Ltd in collaboration with the UK Meteorological Office with funding from the Department of Industry and is expected to take about three years. A preliminary account of the project has already been published. This article briefly recapitulates the case for the new atlas and updates the indication previously given of the proposed form of the contents, which has been revised in the light of comments received. Reference will be included to the plans for an associated database not mentioned in the previous account.
‘Estimating the Pressure Altitude of Aircraft by Radar’
Authors: Nagaoka Sakae
Published: November 2009

Between proof stage and printing, a line in the paper by Dr Nagaoka published in Vol. 37, May 1984, p. 216, was omitted. The paragraph in question should read: ‘9. conclusions. A method for obtaining a rough estimate of the indicated altitude of cruising aircraft from the ground using data taken by a height-finding radar is presented. The data contains the measured height, the pressure and temperature of the air on the ground.’
The Navigational Requirements for Ocean Cable Laying
Authors: Fennessy Edward
Published: November 2009

In his Presidential Address, presented at the Annual General Meeting of the Institute held in London on 19 October 1977, Sir Edward Fennessy, until recently Managing Director Telecommunications at the Post Office, traces the role of navigation in the development of ocean cable laying from the earliest days. Today, telephone cables capable of bearing several thousand telephone conversations link the continents; plans are now well advanced for the laying of a cable between Cornwall and the United States which will provide some four thousand circuits. To lay and maintain these cables calls for all the precision obtainable from the most modern electronic aids to navigation and position fixing, including the satellites.
Early Dead Reckoning Navigation
Authors: Cotter Charles H.
Published: November 2009

The reckoning of a ship is the up-to-date record of the courses and distances made through the water since the ship's position was last fixed by observation. The importance of keeping a careful reckoning was paramount in circumstances when observational methods of fixing were not available. In the early days of sea voyaging, even before astronomical methods for checking position had become available, the mariner who would know his ship's position (essentially to estimate his arrival time at his destination) was forced to rely on his reckoning—no other way was at hand when out of sight of land.
Aeronautical Chart Servicing
Authors: Rosenkrans W. A.
Published: November 2009

The author of this paper, which was presented at a meeting of the Institute in London on 16 March 1977 with Captain B. J. Calvert in the Chafr, is the President of Jeppesen Sanderson Inc. He traces the history of the Jeppesen Company's charts from their early beginnings when map reading and dead reckoning were the only aids to air navigation to their adaptation to modern automated airborne systems.
Depth Sounding from the Air by Laser Beam
Authors: Clegg J. E. , Penny M. F.
Published: November 2009

Aerial photography has revolutionized the art of map making over land and if the depth of water could be measured from an aircraft a similar revolution might be expected in hydrography. In 1971 an airborne laser land profiler, designed and constructed at the Weapons Research Establishment, Adelaide, was put into service. At the suggestion of Captain J. H. S. Osborn, then the Hydrographer, R.A.N., this was modified to profile the sea bed and flight tested in June 1975. It was found that, in the vicinity of Adelaide, reflections from the sea bed could be obtained down to 30 m and in places down to 40 m. With an airborne device it becomes possible to survey an area instead of a line and work since has been concentrated on developing a system which will scan at right angles to the aircraft's track.
Ship Performance in Rough Weather
Authors: Lloyd A. R. J. M.
Published: November 2009

The Royal Navy employs naval architects to design its ships and a number of establishments exist to advise the Director General, Ships, on various specialist subjects connected with warship design. The Admiralty Experiment Works at Haslar, near Gosport, (AEW) which was founded in 1872 by the father of modern naval architecture hydrodynamics, William Froude, advises the Director General on all aspects connected with hydrodynamics. Froude's activities and those of his son R. E. Froude, who succeeded him as Superintendent, covered a wide field but the study of resistance and propulsion in calm water occupied most of their energies. William Froude was indeed responsible for the first real understanding of the mechanism of ship resistance and was able to demonstrate that the resistance of a ship could be accurately predicted from model experiment results.
Drift Angle and its Consequences in Ship Manœuvres
Authors: Meurs K.
Published: November 2009

When manœuvring ships, mariners usually pay a great deal of attention to the rate at which the heading changes but the direction in which the ship actually moves may differ from the direction in which she is heading. This difference may be caused not only by current but also by the ship's drift velocity through the water in a direction perpendicular to the heading. This velocity is hard to recognize but can cause a turning moment on the ship, whether this is desired or not. In difficult manœuvres which cannot always be accomplished by changes of heading only, one can use the effects of this drift velocity. The drift angle, the angle between the heading and the direction in which the centre of gravity moves through the water, must not be confused with the course allowance necessary to make good a track over the ground when there is a current.
Dynamic Simulation: A Tool in Research on Human Behaviour in Navigation
Authors: Lazet A. , Schuffel H.
Published: November 2009

An ever increasing traffic density and the larger dimensions and higher speeds of modern ships all make the task of navigating and manœuvring a vessel more difficult. To make the task easier more emphasis has been placed on the human engineering aspects in the design of navigation bridges and on automation. Increasing automation has changed the man-machine relationship, in particular man is relegated more and more to a monitoring role; predictions about the ultimate of automation, the unmanned ship, have not yet come to pass but the increasing importance of the bridge as a result of automation is certainly recognized. However, to understand the process of steering not only must the layout of the navigation bridge be studied but also the visual impression of the external environment. It is obviously important to adapt the conditions of the working environment to human aptitudes, for this is the only way to enable man to correct and control the system in complex situations. But such an approach demands a general knowledge concerning human aptitudes and it is necessary to study a man's behaviour in varied situations to discover his inherent limitations.
Single-handed Voyages and the Collision Regulations
Authors: Foster L. R. R. , Hasler H. G. , Sleightholme J. D. , Cockcroft A. N. , Wepster A.
Published: November 2009

The 1972 Collision Regulations, which came into force in July 1977, strengthen the injunction on all vessels to keep a proper lookout by making it the subject of a separate Rule rather than including it in a general statement relating to the ordinary practice of seamen. The old Rule which laid down that nothing in the Rules would exonerate any vessel from the consequences of (amongst other things) ‘any neglect to keep a proper lookout’ virtually left what constitutes a proper lookout to the Courts. Rule 5 of the 1972 Regulations is much more specific. It reads: ‘Every vessel shall at all times maintain a proper lookout by sight and hearing as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and the risk of collision’. The Regulations apply in effect to ‘every description of water craft’ although it is reasonable to suppose from their source that the kind of vessel most in mind, unless otherwise stated, is the power-driven ship rather than, say, sampans or dugout canoes.
English Channel Traffic Control
Authors: Vendrell Ian C.
Published: November 2009

With reference to Captain Emden's paper in the April 1975 issue of this Journal, in which he refers to the control and identification of shipping passing through the English Channel, and the numerous articles by Captain Wylie on the subject of computerized shipborne collision avoidance systems, why not adapt the ship-borne radar systems for land based control of Channel traffic ? A modified shore based system would, with present and predicted traffic movement, be ideally suited to this type of application. As to the problem of operator traffic identification and control, the present civil air traffic control procedures would seem to provide the ideal solution; if all shipping were required to carry dual channel multi-code transponders in addition to the current obligatory navaids.
I—A Comparison of Facilities on Computer Based Radars
Authors: Jones K. D.
Published: November 2009

Historically, radar has been villified as a source of the many accidents, either as collisions or strandings, which have occurred around the world since the end of the war. More truthfully the blame should have been laid not so much on the equipment as on the operator, and it would appear from the many court findings that it is the man who has been unable or perhaps unwilling to extract the level of data needed to navigate his ship successfully from the basic range and bearing information that the radar sensor provides. This shortcoming has been recognized for many years and attempts to correct it have been manifold. There has been heavy investment both by shipowners and education authorities to provide simulators, to offer short courses and to provide anti-collision training, and there has been a marked emphasis on the significance of plotting and radar interpretation in the certificates of competency and D.T.I, examinations. Nevertheless, the lessons which it was hoped would breed good radar practice and which were germinated in the classrooms rarely seemed to come to fruition in the more hostile environment of the ship's bridge. The reasons or the excuse for this lack are not hard to find. There is insufficient space, there is no table, the bridge is single handed, there is too much to do. There are numerous excuses or reasons offered. Many of the arguments are well founded, but these tend only to be a cloak for a more fundamental reason, a reason which is rarely expressed.
A Note on Short-method Tables
Authors: Sadler D. H.
Published: November 2009

In my article (this Journal, 1, 290, 1948) on The Provision for Astronomical Navigation at Sea I called attention (p. 302) to the possible advantages of dividing the standard PZS triangle of astronomical navigation into two right-angled (or quadrantal) triangles by a perpendicular (or quadrantal arc) from the pole P to ZS, or ZS produced. In particular I wrote ‘the method is one which might be further explored,…’; it is only recently that I have had occasion to do so. As far as I have been able to discover from the material available to me (including, by courtesy of Captain Charles H. Cotter, a copy of the typescript of his A History of Nautical Astronomical Tables), the only published method or tables using this principle is ‘Tables for the Abbreviated Computation of Zenith Distance and Azimuth of Celestial Bodies’, by Frane Flego (Split, 1957). Unfortunately, as pointed out by W. A. Scott and myself in a review article (this Journal, 11, 207, 1958), Captain Flego failed to overcome some of the technical difficulties of the method.
Using a Hand-held Calculator for Ship's Position Comparison
Authors: Meaden T. R.
Published: November 2009

The author's personal experiences under operational conditions have been with the CBM (Commodore Business Machines) S.R. 4148R, which has proved quite adequate for position comparisons in a surface warship fitted with a Magnavox satellite navigation system primarily used as a DR recorder. It is fed with ship's course and speed, corrections to the positions found being up-dated from satellite passes. Occasionally the criteria for up-dating from a satellite pass are not met and the system may run on DR for several hours without up-dates. Since the system is unable to compensate automatically for tidal or current drift and set or for leeway, the accuracy of the DR will deteriorate with age. The possibility of component malfunction, albeit temporary, may also contribute to DR error. In such conditions a series of astronomical observations is made; the calculator is capable of finding the average of such a series if required.
Error Distribution in Navigation
Authors: Anderson O. D.
Published: November 2009

In an earlier paper the present writer drew attention to the distinction between mixed and aggregated distributions. Incidentally, two minor mis-statements in that paper should be corrected. The first sentence in the last paragraph of section 2 (page 72) should read ‘As σ2/σ1 (=k say) tends to either zero or infinity, X/σ increases indefinitely; whilst for k nearer unity, X/σ is smaller’. Also the last line of the Appendix should not terminate with ‘X/σ = 3·724’ but with ‘X/σ→∞’.

Mixed distributions arise when for example an error occurs either from one distribution with probability p, or from another with probability 1–p, as in a set of position line errors due sometimes to one and sometimes to the other of a pair of observers of differing precision. An aggregate distribution occurs when the error consists of, say, two sub-errors, one from each of the two distributions; as when Captain Flint marks the chart and Long John subsequently reads it.
The Inter-Governmental Maritime Consultative Organization
Authors: Srivastava C. P.
Published: November 2009

This address by the Secretary-General of Imco was given at a meeting of the Institute in London on 10 March 1976, with a Vice-President, Mrs. Mary Pera, in the Chair.

IT gives me great pleasure to be here today and I should like to thank you most warmly for your kind invitation to speak on the work of the Inter-Governmental Maritime Consultative Organization, or IMCO as it is commonly called. Naturally I do not need much encouragement to talk about Imco but I consider this to be a rather special occasion, because of the long and close association between the Royal Institute of Navigation and Imco. I shall advert again and more fully to this association later.

As you know, Imco is a specialized agency of the United Nations charged with important responsibilities in the maritime field. It was established by the Convention on the Inter-Governmental Maritime Consultative Organization, adopted by the United Nations Maritime Conference held in Geneva in 1948. Imco began life in January 1959 and its Headquarters have been in London from that time.
Nautical Astronomy: Past, Present and Future
Authors: Cotter H.
Published: November 2009

Chart, compass and log are the three fundamental instruments of navigation. It was not until mediaeval times, coinciding with the early development of these instruments, that navigation became scientific; and certain it is that without them the opening up of the oceans for exploration, as a preliminary to maritime trade, would have been delayed.

The defects of ‘dead reckoning’ navigation, the process by which a vessel's position may be pricked on a chart from compass and log observations, were of little consequence to medieval navigators whose activities were confined to the Mediterranean Sea and the coastal waters of Atlantic Europe. But following the advent of the Golden Age of Discoveries initiated by the Portuguese in the fifteenth century, when western Europeans first struck out to cross the Atlantic, the pressing need for a reliable method of checking DR positions led to the rise of nautical astronomy. The practice of this art which is secondary to the primary navigational aim of finding the way embraces the traditional methods of mathematical astronomy for ascertaining latitude and longitude. A nautical astronomer requires skill, mathematical and scientific expertise and certain indispensable equipment. A chart for pricking position as a preliminary to setting or rectifying a course, mathematical and astronomical tables to facilitate computations and instruments for measuring respectively altitudes and times; these are the main tools of nautical astronomy.
Two Hundred Years of the Collision Regulations
Authors: Kemp John F.
Published: November 2009

Two hundred years ago a signal book was issued to a Captain Cornthwaith Ornmary of H.M.S. Tartar. The date was 13 June 1776 and the signal book contained the earliest reference which the author has been able to find to a positive rule of the road at sea. The signal book was the work of Admiral Lord Richard Howe, who in 1776 was commanding a fleet off the coast of north-east America in support of his brother G eneral William Howe. Brother William was enjoying considerable success in 1776 but his contribution to history did not survive his encounters with George Washington in 1777 and 1778. Brother Richard meanwhile, perhaps fortunate in not meeting the counterpart of George Washington at sea, went on to add further illustrious chapters to an already distinguished career. His modest rule of the road has not only survived almost unaltered to the present day but it has also formed the basis for our entire system of rules for preventing collisions between ships.
New Prospects—The Structure of Sea Lanes
Authors: Richardson R. B.
Published: November 2009

There has been considerable progress within the last three years in the evolution of various traffic procedures in coastal and waterway areas. Society at last seems to be awakening to the need for some order and conformity as a means of protecting the marine environment. And sea people have accepted that communications—like steam—have altered the face of the Earth. Learned societies and professional institutions have each played their part on the new frontiers of sea affairs and we have between us not been backward in promoting our ideas as to what the new order could be. We begin to acknowledge that we belong to our times.

We have used the bones of Torrey Canyon and her more recent successors in the Dover, Magellan and Malacca Straits to climb out of an age of obstinate rejection into one of enlightened self-help. Modern life does not tarry with yesterday, and the headlines of past accidents are not necessarily the right titles for future remedies. But they are very useful pointers along the way. Perhaps at last we have understood the nature of the traffic question and can now begin to seek the answers with a broader base of consensus.
System Problems in Air Traffic Control
Authors: Ratcliffe S.
Published: November 2009

Air Traffic Control is part of the process by which aircraft ‘go about their ways’ and thus can fairly be regarded as a branch of navigation. Because of the existence of centralised control organizations, and because much of the total flight time is spent in the vicinity of system ‘hubs’, air traffic interacts with itself in very complex ways. For this reason the traffic as a whole behaves in a manner that could not easily be predicted from an inspection of the system elements. Thus there can be said to be a ‘system’ problem, where by a system is meant, not the specific hardware but the abstract elements which determine the essential overall performance. These abstractions would, for example, be common to a computer simulation of an ATC system and to its real-life counterpart. The present paper will attempt to discuss, at this ‘system’ level of abstraction, the problems facing air traffic control and the principles on which the system design should be based.
Polish Cartography in the Sixteenth and Seventeenth Centuries
Authors: Wereszczyński Jan
Published: November 2009

Dr. Jan Wereszczynski, a member of this Institute, describes the little known Polish contribution to the mapping of eastern Europe at a time when interest in maps of the known world had been stimulated by the rediscovery and publication of Ptolemy's great work on Geography, written in the second century AD and forgotten during the Middle Ages.

The history of the cartographical development of the Baltic and Black Sea coasts reveals a significant contribution from Polish cartographers in the sixteenth and seventeenth centuries. The ‘father of Polish cartography’, and one of the most famous scientists of his day, was Bernard Wapowski (1450–1535) who published two maps of Sarmatia. One covers the northern part of the Balkan peninsula, a large part of the Grand Duchy of Lithuania, the Crimean Khanate and part of the Grand Duchy of Moscow. The other covers the country north of a line from Toruri to Novgorod. It should be emphasized that Wapowski's geographical coordinates are of outstanding accuracy, most of them, especially the latitudes, being based on his own astronomical observations.