bluuebunny/crossref_metadata_2025 huggingface dataset:
The Reduction of Sea and Rain Clutter in Marine Radars
Authors: Croney J.
Published: January 2010

This paper is concerned with measures which may be used to reduce the effect of echoes from the sea surface and from rain (sea and rain clutter) on radar displays so that targets which give a reflected signal power greater than the reflected clutter power can be detected. It should be noted that a conventional PPI display is fully brightened by signals of amplitude about three times the level of the inherent noise background, so that once the clutter has exceeded this limit it will appear on the display as a fully bright patch in which signals can be lost, even though their amplitude at the receiver input may be many times greater than the amplitude of the clutter.
Radar and Collision at Sea
Authors: Fellingham H. C. , Forrest G. C. , Hutton A. H. , Morgan F. W.
Published: January 2010

In the July number of the Journal (Vol. VI, p. 313) Captain F. J. Wylie suggested that members and other readers of the Journal should contribute their suggestions as to rules of conduct to be observed by ships using radar in fog. It is possible to print only a selection of the comment received, but all the contributions sent in have been made available to the Technical Committee.
The ‘Dyoll’ and the Bearing-dial
Authors: Naish G. P. B.
Published: January 2010

There has recently been some discussion in the Journal1 as to the meaning of the word ‘dyoll’ when it appears in English ship inventories of the years 1410–12, which have been partially published, by Nicolas2 and Sir Alan Moore.3 Nicolas quotes from the Accounts and Inventories of John Starlyng, Clerk of the King's Ships to Henry IV, but he mistakenly dates these documents 1338, which date has been corrected by Moore to 1410–12.
Astro-Fix by Computation
Authors: Collins Oliver C.
Published: January 2010

This paper describes a method for the reduction of simultaneous star altitude observations in pairs, whereby an unambiguous ‘fix’ is obtained without reference to the dead reckoning position and without use of the intercept procedure. The method is adequate in all latitudes. An especially swift reduction is possible for the moments at which two stars are situated at equal altitudes.

When position is determined by means of two simultaneous star altitude observations and use is made of a single chosen position it is possible for the Marcq St. Hilaire intercepts to be so short that they can be regarded as negligible. When this occurs the chosen position is, in effect, the true position as indicated by the observations and no further work is required for a fix. If, in such a case, it is desired to have the Sumner lines of position represented on the chart it will be possible to draw them through the chosen position. The selection of such a chosen position may be made with certainty, in every instance, by computing numerical values for the latitude and the longitude of the appropriate intersection of the two circles of equal altitudes corresponding to the corrected observations. If the entire computation had to be done after the observations were made, the labour of this procedure would prohibit its use in rapid navigation. It happens, however, that the greater part of the work can be precomputed and presented for the navigator's use in a tabular form. These data are extremely compact and are permanent except for the need of occasional adjustment for precessional effects and on account of proper motions of the stars. No almanac would be required for use with such a table if the navigator were not dependent on it for his G.H.A. Aries. No knowledge of the dead reckoning position is employed in this computation; star observations suffice to determine the position without ambiguity.
Lessons from some Collisions and Groundings at Sea
Authors: Nichols C. A. G.
Published: January 2010

In this paper two collision cases and four cases of ships grounding will be examined and the circumstances analysed with a view to drawing some useful conclusions from them. In the case of the collisions no general theory can be advanced but they both have a navigational interest from the point of view of the International Regulations Jor Preventing Collisions at Sea and a certain amount of useful comment can be made on them.
Improving the Radar Performance of a Buoy: An analysis of results before and after fitting a reflector
Authors: Cashmore D. J.
Published: January 2010

The King William Banks buoy is situated about 12 miles east of the northern tip of the Isle of Man. It marks the eastern extremity of the bank of this name and is an important turning point, especially for the British Railway ships on the Heysham to Belfast run. This buoy, which is unlit, is a third class spherical buoy and thus presents a poor radar target. The British Railway ships are fitted with radar and always pass the buoy at night so that if it could be detected by radar regularly it would be of great assistance to navigation. In fact complaints were made about its radar reflecting properties, and accordingly a pentagonal cluster of 12 in. corner reflectors designed by the Admiralty Signal and Radar Establishment was supplied to Trinity House and mounted on the buoy on 3 March 1949 (see Notice to Mariners 619/49) at a height of 11 ft. 6 in. above the water.
Automation in Marine Navigation
Authors: Wylie F. J.
Published: January 2010

Automation has proceeded much further in connection with air navigation and air traffic control than it has in comparable aspects of the maritime service. There are many factors to account for this. By its nature, air travel involves risks which are greater and more urgent than those of sea travel and which, in focal areas, are high in all conditions of weather; its passenger/cargo ratio is vastly greater and this inevitably stresses the need for every possible aid to safety. These characteristics and others more obvious lead to ground control, control leads to centralization and uniformity and thus to the ready introduction of advanced developments and their imposition where appropriate on the airborne user.
The Significance of Blunders
Authors: Majendie A.M.A.
Published: January 2010

Most of the Ordinary Meetings of the Institute provide an opportunity for specialists to report on work that has been carried out, or experience that has been gained. From time to time, however, we have a meeting designed specifically for the purpose of discussion. The main aim of such meetings is to enable interested persons, with quite different backgrounds of knowledge and experience, to come together and consider collectively a subject of common interest from their various viewpoints. The present discussion is on the significance of gross human errors and blunders in navigation.
Man and the Machine
Authors: Colquhoun W. P.
Published: January 2010

Future transport systems are difficult to predict, but one can perceive three main possibilities. The first is that transport will become entirely automatic, so that where, for example, one now has an automatic pilot during flight, one will also have automatic take-off and automatic landing. Flights will be pre-programmed, and will require no supervision in the vehicle itself or even from a remote-control room. Whether or not such a system is practicable is not within the scope of this paper; but there does not appear to be any purely mechanical problem connected with it that could not be overcome. However the production of equipment of the necessary reliability raises formidable human problems. problems. Not the least among these is the difficulty of maintaining rigorous standards of inspection; another is the rationalization and speeding up of faultfinding and repair procedures. It looks as though if we were to dispense with the human element in one sphere, its importance in another would be enhanced.
Blunders as the Cause of Collisions and Groundings at Sea
Authors: Jowitt J. E.
Published: January 2010

Certainly genuinely unavoidable aberrations in human behaviour exist. In surface navigation, however, these momentary blunders seldom lead to fatalities such as collisions or groundings, although in shiphandling they can cause collisions when coming alongside or when manoeuvring in a confined space, but usually only of a minor nature.

The examination in the R.N. Navigation School of some sixty collisions and groundings has revealed that in only two have aberrations played any significant part in the subsequent disaster. This is quite easily explained for two reasons. First of all ships at sea usually close one another or approach a danger at a comparatively low speed. Furthermore the prudent mariner reduces speed when danger exists and when the situation becomes tense. There is therefore usually time for the nature of a blunder to be recognized and for the necessary corrective action to be taken, which, if not resulting in immunity, will reduce the gravity of the incident. Sixty knots is an exceptionally high relative speed on the surface, yet this provides minutes for human reaction as opposed to seconds or even split seconds normally available in the air.
Radar and the Collision Regulations
Authors: Oudet L.
Published: January 2010

However much opinions may vary as to the proper way to treat the problems raised by the use of radar, there is no doubt that something must be done to help navigators resolve them. The International Conference on Safety of Life at Sea held in London in June 1948 saw fit to declare in its Recommendation No. 19 that the possession of radar in no way relieves a vessel from the obligation of strictly observing the requirements laid down in the Rules for Preventing Collisions, and in particular with Rules 15 and 16 (sound signals in fog, moderate speed in fog, &c). It is common knowledge that navigators have not found constructive guidance in this text, and accidents have multiplied. It has been argued that the increase in accidents has not been proportionately as great as the increase in tonnage, but the argument is not very weighty. In the first place, accidents have become particularly serious because of the size and crossing speed of ships; and in any case it is a poor consolation to masters anxious to observe the Rules, but not quite certain how to do so, to be told that there is no cause for anxiety as there are not as many accidents as all that. This argument, even if it does not actually discourage navigators anxious to observe the Rules still runs the risk of making hesitant navigators err on the wrong side. It is therefore necessary to do something, and the first thing seems to be to state the problem concisely.
The Measurement of Wind from Aircraft Using a Doppler Navigation System
Authors: Murgatroyd R. J. , Helliwell N. C.
Published: January 2010

The accuracy of winds measured in flight using a doppler navigation system has been investigated by comparison with simultaneous measurements from a Meteorological Office radar wind-finding station and also by flying different tracks using a modified multiple-drift technique. The errors of wind measurement arise from errors in the ground-speed vector as measured by the doppler navigator and also from errors in the true airspeed vector as obtained from the readings of the airspeed indicator, altimeter, outside air thermometer and compass. The trials, which were made at various altitudes to 48,000 ft. in a Canberra aircraft of the Meteorological Research Flight, showed that, providing suitable in-flight calibrations are carried out, the error in the vector wind can be reduced to about 5 kt. but that without these calibrations it may be 10 kt. or more.
Polynesian Navigational Stones
Authors: Hilder Brett
Published: January 2010

In this paper, a group of eight directional stones on the coral island of Arorae in the Gilbert Islands are described. The stones seem to have been used to direct canoe voyages to distant islands with the help of horizon stars en route, the stars' movements and bearings being studied and memorized in relation to the correct stone on the night before departure. They perhaps mark the site of a Polynesian navigation school which existed somewhere between A.D. 1000 and 1500. The directions given by the stones appear to have been corrected for drift due to the Equatorial Current. So far as is known these stones are unique, and have not previously been reported in print.

On the island of Arorae in the Gilbert Islands there is a group of eight or nine stones which are said by the natives to have been used by early canoe voyagers to set their courses on departure to distant islands. No other such stones for navigation have been reported from the Pacific, which makes the coral stones of Arorae of unique value in the history of navigation. The stones are some of the few pieces of real evidence in the long-standing controversy on the nature and range of Polynesian navigation. The stones are called ‘Atibu-ni-Borau’ by the natives, which means ‘stones for voyages’. They have no legends or traditions which shed any light on the origin or actual use of the stones, but there are several clues available from elsewhere in the Pacific which enable the use of the stones to be determined with a high degree of probability.
The American Plan for Air Traffic Control: A Description of SC31
Authors: Fraser D. O.
Published: January 2010

In May 1948 the Radio Technical Commission for Aeronautics, a cooperative association of United States government and industrial air telecommunication agencies, issued a report outlining a comprehensive scheme for the development of air traffic control facilities in U.S.A. for the next fifteen years. This report was prepared by a committee set up by the R.T.C.A., Special Committee 31, and it is generally known as the SC31 Report. It was the result of a study undertaken at the request of the Technical Division of the Air Coordinating Committee, an inter-departmental committee established by the Secretaries of State, War, Navy and Commerce, and directed by the President to examine aviation problems of mutual concern and to develop and recommend integrated policies and actions to be taken for their solution.
The Sensory Basis of Bird Navigation
Authors: Matthews G. V. T.
Published: January 2010

The problem of how birds find their way can be examined by studying natural migration movements and also by forcing birds to undertake long journeys more or less under conditions which can be decided by the experimenter. The racing pigeon is an ideal subject for these homing experiments, but they have also been conducted with many species of wild bird and Fig. i shows some of the more remarkable flights that have been achieved with these. The use for these experiments of birds breeding in colonies has many advantages as large numbers can be caught and transported together, and their return watched for in a small area. Conspicuous birds such as gulls can be made individually recognizable by a code of plumage marks or by putting coloured leg rings on them.
Ocean Navigation in Small Craft
Authors: Bruce Erroll
Published: January 2010

The plan. During the spring and summer of 1950 three small British yachts sailed 15,000 miles in the open Atlantic, the object being to compete in the Bermuda race and then to race back across the Atlantic to Plymouth. Two of the craft, Cohoe and Samuel Pepys, were of under 5 tons displacement and the third, Mokoia, was very little bigger.
The Foundation and Early Development of the Nautical Almanac
Authors: Forbes Eric G.
Published: January 2010

Soon after the middle of the eighteenth century, improvements in the design and construction of astronomical and nautical instruments, coupled with the increased accuracy of tables of the Moon's motion, at last made the accurate determination of longitude at sea by lunar distance a practical possibility. The Astronomer Royal, Nevil Maskelyne, was quick to appreciate the importance of publishing the calculated solar and lunar ephemerides, together with other relevant tables and explanations, in the form of a Nautical Almanac, which was first printed under his supervision in 1766 and immediately distributed to mariners in different parts of the world. The present article is concerned with the circumstances relating to the origin and development of this publication during the first fifty years of its existence.
An A.T.C. Survey of North Atlantic Navigation Problems
Authors:   U.K. National Air Traffic Control Service
Published: January 2010

This paper discusses a method for determining the collision risk implicit in horizontal and vertical separation standards which has been developed in the U.K. in accordance with Recommendation 7/1 of the RAC/OPS Divisional meeting. The acceptable collision risk for the North Atlantic is assessed; this must be related to airworthiness criteria and an accident rate of one in ten million is adopted. It is concluded that no immediate change in separation standards can safely be made but that the standard of navigation should be improved to allow a 90 n.m. standard; that with more data a 1000- or 500-ft. vertical separation may prove to be safe; and that longitudinal separation standards require further study. The improvement in traffic capacity which would result from changes in separation standards is also considered.

This and the following nine papers were presented at the 16th I.A.T.A. Technical Conference, of which a report appears opposite. An analysis of long-range air traffic systems made by the Mathematics Department of the Royal Aircraft Establishment for the Ministry of Aviation was presented in several preliminary papers at the Conference. These studies will be described in a series of papers specially prepared for the Journal.
Vertime
Authors: Anderson E. W.
Published: January 2010

Vertime is a system devised to solve the problem of navigation in the vertical plane. By use of existing navigational aids together with only small additions to cockpit instrumentation and controls, a flight path in the incline plane is defined which the pilot can follow from cruise altitude to end of descent point. In addition, provision is made for improving the accuracy of E.T.A.s at the end of descent. This system reduces pilot work-load in the cockpit, ensures an operationally efficient descent from cruise altitude and will be of material assistance to A.T.C.
Automatic Star-Trackers for Long-Range Navigation
Authors: Thomas Ronald D. , Shroyer Gerald J.
Published: January 2010

This paper describes development trends of one particular navigational technique (automatic star tracking) and its associated instrumentation methods one of which, the application of pulse code modulation theory to sensor design, is discussed in detail. Plans for the future development of this most promising concept are also included and the effects of military research and development efforts on civilian aircraft requirements are indicated. An appendix provides a glossary of special terms used.

Automatic star-tracking systems have been used in military aircraft navigation for position fixing and heading correction for a number of years and the development of the equipment has been actively pursued by the U.S.A.F. since as early as 1946. Basically, star trackers are automatic devices that probe a portion of the celestial sphere for the purpose of detecting, acquiring and tracking stars or other celestial bodies. In using astronomical inputs for cruise vehicle navigation, advantage is taken of the well-known principle that sights on two or more stars when referred to the true vertical and time can be used to provide a position fix. It is the intent of this paper to review techniques used to instrument star trackers, discuss their application to long-range aircraft navigation, indicate development trends and introduce a new concept of employing pulse code modulation theory to the design of a simple, low cost automatic astro-tracker.
Some Suggestions on the Rules for Preventing Collision at Sea
Authors: Kemp J. F. , Calvert E. S. , Burger W. , Corbet A. G. , Fricker F. W. , García-Frías J. , Hugon P. , Oudet L.
Published: January 2010

A paper by Captain J. F. Kemp under this title was published in the April number of this Journal together with some comments on these proposals. Further contributions to the discussion and a reply from Captain Kemp are printed below.

In the April issue of this Journal Captain Kemp has put forward a carefully considered proposal for making the Rule of the Road more effective. His proposal is well considered because he is aware of the audacity which its careful presentation conceals; he is also careful to suggest a change in the Rules only as a basis for discussion. His suggestion is precise, for it is simply to extend Rule 18 to all encounters, or in other words to require both vessels, when crossing or overtaking, to rotate the line of sight in the normal direction as required in Rule 18.
II.—Tables for the Reduction of Astronomical Sights
Authors: Sadler D. H.
Published: January 2010

The purpose of this lecture is to review briefly the many methods at present available for the reduction of astronomical observations, and to make suggestions for the future. The main conclusion will be that altitude-azimuth tables provide the simplest and quickest method of reducing a sight.

It should be made clear that this is not a comprehensive survey setting out to examine and criticize every method; the bibliography of papers and tables (itself incomplete) published by H. Bencker in The Hydrographic Review, which contains some 1200 references, indicates that such a task would demand months of research. Attention is directed towards the principles of the various methods, and the limitations of each principle are discussed independently of the actual tables existing for the application of the method.
Operational Research into the Air Traffic Problem
Authors: Bowen E. G.
Published: January 2010

In a recent issue of Nature Sir Charles Goodeve gave an illuminating account of the value of operational research in war and described how, in peacetime, similar methods were being applied to problems of rail and road traffic. It is significant that he was unable to give examples of similar investigations into the flow of air traffic.
The Magnetic Compass: A Survey of Developments
Authors: May W. E.
Published: January 2010

The paper is divided into two parts. The development of ship-borne compasses is reviewed in Part I; in this section some of the difficulties due to bad siting, &c., are mentioned and certain solutions such as the use of repeating compasses and improved methods of correction are described. Part II surveys the development of the aircraft compass and shows how its phases of development have corresponded to those of the marine compass. Some recent forms of aircraft compass and methods of development are also described.
Is Forecasting Necessary?
Authors: Chichester Francis
Published: January 2010

Twenty years ago meteorological forecasting was necessary and important to aviation. A number of factors made it so, as a short review of flying conditions in those days will show.

The weather was then the dominant factor in training. The wingloading of training aircraft was then so light that a sudden variation of only 10 m.p.h. in the wind made a practice landing hazardous. Both pupil and instructor therefore anxiously awaited the weather forecast. The wind forecast was equally important to the transport pilot of 1928 when a headwind of 60 m.p.h. was likely to prevent his reaching a destination only 200 miles away.
Errors in Observed Altitudes
Authors: Clemence G. M.
Published: January 2010

On page 179 of the first volume of the Journal, Commander J. Middendorp, R.N.N.R., discusses the effect on the observed altitude that arises when the sextant is tilted out of the vertical plane, and concludes that the error is a maximum for altitudes in the region of 45; it seems to me that the conclusion is incorrect. I have no quarrel with Commander Middendorp's mathematics, but with his fundamental hypothesis, which is that when a sextant is tilted it is rotated about the line of sight to the star. I believe on the contrary that a sextant tilt is a rotation approximately around a horizontal axis.
Acceleration Errors in Astro-navigation
Authors: Parker J. B.
Published: January 2010

Squadron Leader Bower gives some data regarding the accuracy of astronomical navigation in high-speed aircraft. No attempt was made to assess the absolute accuracy of astro-navigation, but the distance, when plotted on the chart, between pairs of sights taken on the same star was measured, with the following results.

The average spread between beam shots is consistently greater than that between fore and aft shots, and it is possible that acceleration errors, which can be sizable for high-speed aircraft, are responsible for this.

Errors Due To Aircraft Accelerations. Errors due to the combined effect of the aircraft's movement and the Earth's rotation give rise to errors in the position line.
The Submarine Morphology of certain Port Approach Channel Systems
Authors: Robinson A. H. W.
Published: January 2010

Many of the major ports of the British Isles, including two of the most important, London and Liverpool, are situated at or near the head of sand-filled bays or estuaries. Their continued utility depends not only on the provision of adequate berthing facilities within the harbour area itself but also on the maintenance of a deep-water approach channel through the shoals of the outer estuary. In some cases the latter requisite is the more difficult of the two to achieve, especially where the bottom configuration is liable to considerable change over a relatively short period of time.

The problems connected with a changing sea-bed configuration come within the scope of loose-boundary hydraulics, a branch of flow mechanics which has only begun to be investigated. Some success in this direction has already been achieved using scale models of specific areas but many unsolved problems remain and much remains to be done.
An Analysis of the Navigator's Task
Authors: Latham F. , Spencer J.
Published: January 2010

The growing complexity and variety of navigator techniques and equipment, associated with a marked increase in aircraft speed, necessitates a more detailed investigation of the navigator's task. Despite an increase in the range and automaticity of navigational aids, the demands made upon him are changing their character, and are in danger of being excessively high.

A detailed recording of navigator activity in flight seems the only practical approach to this problem. The knowledge gained by such a task analysis would be expected to furnish information on the following aspects:

(a) Objective evidence of fatigue effects.

(b) The effects of experience on the navigator's work pattern.

(c) The need, if any, for the modification of training methods.

(d) Equipment layout and design in relation to efficiency.

(e) Practical specification of the navigator's layout.

(f) Indications of specific situations which may with advantage be subjected to laboratory investigation.
Observational Errors: A Monograph on the Use of Statistics
Authors: Anderson E. W. , Parker J. B.
Published: January 2010

The monograph which follows has been prepared for the Institute by Wing Commander E. W. Anderson and Mr. J. B. Parker, working closely with Mr. D. H. Sadler. It was designed primarily for publication in book form; however, the Council has decided to publish it in the Journal as well, so as to give it the best possible circulation among members. This arrangement has meant varying slightly the normal style of presentation in the Journal and apart from the title page and page numbers there is no difference between the published book and the pages which follow.
Automatic Dead Reckoning Navigation Instruments for Aircraft
Authors: Pritchard H. C.
Published: January 2010

The development of automatic dead reckoning navigation instruments owes its main impetus to the needs of the airman during the second world war. It was foreseen that manual plotting would not be adequate, for example, in bomber operations where frequent changes of course are desirable and speed and height are not always accurately maintained, and it was realized that automatic computing of position would provide improved reliability and accuracy. The instruments developed have been described elsewhere, and this paper outlines their early history rather than details of their design. It also indicates some future possibilities.

Existing instruments. The main instrumental aids to dead reckoning navigation which came into use during the 1939–45 war were the distant-reading gyro-magnetic compass, the air mileage unit and the air position indicator. From them evolved the ground position indicator and the wind finding attachment, both used for special purposes towards the end of the war.

Early in the 1930's Captain L. C. Bygrave constructed an experimental instrument which undoubtedly influenced later developments. This instrument was to be fed by a gyro-magnetic compass with heading and from an air log with air distance; on it could be set wind speed and direction and aircraft speed and course. The instrument showed departure in miles north-south and east-west.
A Microwave Course Beacon
Authors: Milwright A. L. P.
Published: January 2010

IT has long been realized that the small fishing craft are inadequately supplied with modern navigational aids, and the reason why the most modern aid, radar, is not used is because its cost, weight and electrical power requirements are too great. In Great Britain a large number of small-boat fishermen, for instance in the herring drifter fleets, use Consol for offshore navigation, but this is not sufficiently accurate for navigating into harbour in bad visibility.

In 1951 the National Research Council of Canada undertook the development of a microwave course beacon as an aid to entering harbour. In 1953 the Ministry of Transport & Civil Aviation Group at the Admiralty Signal & Radar Establishment undertook the development of a similar beacon with a view to simplifying the shipborne equipment.

The beacon system is an adaptation of the old Lorenz type aircraft landing aid and consists of a microwave radio transmitter mounted at a harbour entrance and radiating in turn from each of two aerials which have beams overlapping in the horizontal plane. The transmitter is so sited that the line of intersection of the two beams lies along the safe course line for entering harbour. (Fig. 1 shows the orientation of the beams at the Scottish fishing port of Arbroath.)
I—Animal Navigation
Authors: Matthews G. V. T.
Published: January 2010

Before considering what animals can do, without conscious thought, in the way of navigation, it would be useful briefly to review their ability to pilot themselves, to find their way around an area in which they have already had experience. Here landmarks play an obviously vital role, and in many cases they are visual landmarks which we can appreciate ourselves. But often the characteristics of the environment to which the animal reacts are non-visual, detected by senses similar to ours but of much higher acuity. The sense of smell is of dominating importance among the mammals, which will go so far as to provide their own ‘scent flags’ along the boundaries of their private preserves. Sounds are often used to guide animals, particularly to another member of their species or to their prey. The bats have gone further and rely on a form of echo-location for guidance of their fast erratic flight through the darkness. They emit high-pitched, if not supersonic squeaks and detect and analyse the reflections back from obstacles even so slight as a piano-wire stretched across their path. Animal ‘sonar’ of this kind has also been demonstrated in a bird and probably is also to be found in fish and porpoises. Certain snakes are believed to detect their warm-blooded prey by special heat-receptors in the head. Many other examples could be cited and our knowledge of the means by which animals can determine their course in familiar territory is probably not yet exhaustive. We are only just beginning to appreciate and understand what they can do when they are in completely unfamiliar areas or when, known landmarks are present but cannot be used.
The Region of Collision
Authors: Wylie F. J.
Published: January 2010

Two problems concerned with the use of radar to reduce the risk of collision are frequently called to mind by reports of casualties and correspondence relating to them. One is that of avoiding the ‘region of collision’ and the other is how best to proceed within such a region when it is unavoidable. The writer's attention was recently drawn to that phrase as it was used in 1932 in the judgment of the Court of Appeal on the collision between Haliotis and Chisone. The phrase caught the eye because of the need (in the writer's view) of a striking term to appeal to the imagination of some incautious mariners and impress them with the undesirability in fog of leaving too much to chance; it seemed to have more significance than the term ‘close-quarter situation’.

In the case in question the Chisone was found partly to blame because she did not stop her engines until five minutes after hearing the fog signal of the Haliotis. Although she was stopped, or nearly so, some minutes before the collision, she had come directly into the path of the Haliotis and so was considered to have committed the breach of Art. 16 (Rule 16 (b)) ‘in the region of the collision.’
An Eighteenth Century Voyage
Authors: Clissold P. C. H.
Published: January 2010

A recently discovered ‘Navigational Notebook’ contains an interesting account of day-to-day navigation during the early part of the eighteenth century. The document was brought to light by Mr. J. R. Timms, a student at the School of Navigation of Southampton University, whose father discovered it in a bank at Ventnor, Isle of Wight, its depositor long deceased and no longer known or traceable. The date of the manuscript is uncertain but references to John Robertson's Elements of Navigation and Archibald Patoun's Epitome seem to place it after 1730. However the account of actual navigation is given in the journal of a voyage, in 1704, from the Lizard to Madeira, which is reproduced in the Notebook. It seems likely that the author, John Wilson, eventually came ashore as an instructor in navigation (and probably mathematics) and copied out the journal from one of his earlier voyages for the benefit of his pupils. Whether this is a later work by the John Wilson referred to in E. G. R. Taylor's The Mathematical Practitioners of Tudor and Stuart England is not clear.
All Plain Sailing
Authors: Taylor E. G. R.
Published: January 2010

‘The Earth is an ellipsoid’, says the Admiralty Navigation Manual firmly, although in a later volume the expression is softened to ‘approximately ellipsoidal’, For in fact, as was implied by Captain Topley, the exact shape of the Earth is not yet known. Nevertheless, for nautical purposes it appears sound teaching practice to consider it a perfect sphere and then explain the departures of the nautical mile or minute of arc from its mean value. Nor need one quarrel with the Manual's statement that ‘to regard certain small triangles as plane is not to disregard the initial decision to regard the Earth as a sphere’. But the writer next indulges in an historical aside which cannot be allowed to pass. ‘This assumption (he says) gives rise to the expression plane sailing, which is popularly referred to as if plane were spelt plain and the sailing were free from difficulty’. But this is to put the cart before the horse. ‘Plain sailing’ was the original term, and it was only sophisticated into ‘plane sailing’ during the eighteenth century by teachers of navigation among whom John Robertson was the chief. Robertson was master at the Mathematical School of Christ's Hospital towards the middle of the century, and afterwards taught at the Portsmouth Naval College, finally becoming Librarian to the Royal Society. His Elements of Navigation was considered authoritative and ran into many editions, a later master at the Hospital, James Wilson, prefixing to it a Dissertation on the history of navigation which was also accepted as definitive. It is in this volume that we read: ‘Plane sailing is the art of navigating a ship upon principles deduced from the notion of the Earth's being an extended Plane. On this supposition the meridians are esteemed as parallel right lines…’, and the author goes on to what he terms the Plane Chart, with its equally-spaced meridians. There is little doubt that his passage is the source of the theory taught to modern sailors that ‘Plain Chart’ is a corruption of ‘Plane Chart’, while the latter was drawn by people who believed the Earth was flat. Actually we have only to go back a generation from Robertson to find an almost identical description of the chart—actually an equal-spaced conventional cylindrical projection of the sphere—but with the addition of the words ‘The rectangle formed by these meridians and parallels they (i.e. mariners) call the Plain Chart’. This was said in 1714 by John Wilson, a teacher in Edinburgh.
Early Pole Star Tables
Authors: Waters D. W.
Published: January 2010

I think Professor Taylor and I are at cross-purposes in our discussion of the influence of scientists upon the art of navigation before the nineteenth century. Dr. Freiesleben expressed the view that until 1800, ‘when our technical age began’, there was a big gap between what interested scientists and what the seaman could understand and apply, that men of science were too remote from practical requirements. The implication was that scientists were not concerned with seamen's problems nor seamen with obtaining scientific help. I pointed out that whatever the situation in the eighteenth century might have been, in the sixteenth and early seventeenth centuries improvements of a radical nature were made by scientists, working with and for seamen, in the means of practising the art of navigation, in particular by English scientists working in the latter part of the period under the aegis of Gresham College and the East India Company. This is historical fact, little known perhaps, but none the less fact. I certainly never intended it to be understood that the seaman-scientist relationship peculiar to this period and resulting in such important developments typified, to use Professor Taylor's expression, ‘the degree of cooperation between sailor and scientist prior to the nineteenth century’. I intended it to be understood as being descriptive of the situation or relationship peculiar to the period in which it occurred, roughly 1550–1640 and more particularly 1598–1637.
A Note on the Relative Wind
Authors: Hilder Brett
Published: January 2010

In taking observations of the wind at sea, and in the study of the theory of air-navigation, it is often found difficult to give students a thorough conception of the relative (or apparent) wind. These notes are put forward to help instructors and others interested.

It is recorded that one of England's early Astronomers Royal went sailing on the Thames about 200 years ago, and what he learned that day made an advance in the science of astronomy. The Astronomer Royal was with some professional sailors, who must now be spiritual members of the Institute of Navigation. The learned gentleman was the Reverend Dr. James Bradley, who gave up his vicarage to become a professor of astronomy. The day in question had a wind of force four or five, but it was a steady wind, and the boat was tacking frequently.

At the masthead she wore a pennant, referred to by the doctor as a ‘vane’, and he noticed that it tailed away steadily enough down wind. But every time they went on to the other tack the direction of the pennant altered. The doctor was surprised that the wind should happen to alter every time they put about, but on mentioning this to the sailors he was told that the pennant only showed the direction of the relative wind, depending upon the direction and force of the true wind and the direction and speed of the boat, and their resultant changed every time they went about.
An Experiment in Polynesian Navigation
Authors: Lewis David
Published: January 2010

Dr. David Lewis, after completing the single-handed transatlantic race in 1964, sailed his catamaran Rehu-Moana through the Magellan Strait to Valparaiso and on to Easter Island and Tahiti. From Tahiti he sailed to New Zealand.

In an earlier paper published in the Journal (17, 278) Dr. Lewis reviewed the background to and evidence for various theories about early Polynesian navigation. One of his conclusions was that they must have been able to determine both course and, in effect, latitude with sufficient accuracy to make a landfall within the area of known groups of islands and so to proceed to any intended destination. This paper aroused considerable interest and was the subject of numerous contributions to the Journal, in particular from Andrew Sharp (18, 244) and Brett Hilder (18, 246).

In a series of communications written on board during the voyage to Tahiti, Dr. Lewis discusses the objections raised to some of his hypotheses. These cannot be dealt with here. On the voyage from Tahiti to New Zealand, via the Cook Islands, however, Dr. Lewis attempted to demonstrate, by navigating without instruments, that the methods used by the ancient Maoris were sufficiently accurate to make the voyages attributed to them navigationally feasible. It is this voyage that is related here.
The Parallel-route System for North Atlantic Subsonic Jet Traffic
Authors: Attwooll V. W.
Published: January 2010

In the first of this series of papers, the general principles of costing the effect of air traffic control deviation were discussed. This paper discusses the application of these principles to a model route structure for North Atlantic subsonic jet traffic. It is shown how the, design of an optimum system is related to cost considerations and how the cost depends on variations in traffic intensity and on the level of separation standards in all three dimensions. The work on which the paper is based was carried out at the Royal Aircraft Establishment.
Separation Standards and Aircraft Wander
Authors: Lord R. N.
Published: January 2010

The basic parameters leading to aircraft navigational error are combined statistically and are used to evaluate the uncorrected deviation (wander) to be expected in both subsonic and supersonic transport aircraft operating in a typical trans-oceanic environment. The size of the across-track and along-track wander before any form of corrective control is applied indicates the physical size of the A.T.C. block of airspace necessary to contain the aircraft. The variation of block size with the forward prediction period used by A.T.C. is presented graphically. The effect of improvement in the basic sources of error is demonstrated and it is seen that for the S.S.T. era attention must be turned to effecting improvements in aircraft heading and airspeed holding capabilities.
Admiral Marcq de Blond de St. Hilaire
Authors: Duval R. Ch.
Published: January 2010

In America and Great Britain people are on the whole well acquainted with the picturesque circumstances surrounding the discovery of the ‘line of position’ by the Merchant Navy captain, Thomas Sumner. On the other hand, less has been written about the personality of Admiral Marcq de St. Hilaire, and about his work which led him to propose the comprehensive and exact method, now universal, which bears his name. My intention, therefore, is not to go back over the theory or the practice, nor even the value of this system of position finding by comparing points. It is just a question of making this brilliant naval officer better known, his upbringing, character, and the historic circumstances of the perfect achievement of which he is the immortal author.
The Use of Computers in Merchant Ships
Authors: Hugon P.
Published: January 2010

This paper gives an account of a study carried out by the Institut Français de Navigation for the Administration de la Marine Marchande. The object of the study was to investigate the possibilities of introducing automation into the navigation of merchant ships. In addition to examining projects already underway in France and other countries, the Institut Français de Navigation sought the cooperation of numerous companies working in the electronics and computer fields and notably the Compagnie Générale d'Automatisme (C.G.A.), Compagnie Européenne d'Automatisme Électronique (C.A.E.) and Compagnie Générale de T.S.F. (C.S.F.).

Only the main features of this study are described here. Professor Hugon is Secretary-General of the French Institute.
Multi-mode Weather Radar
Authors: Thorne T. G.
Published: January 2010

Weather Radars. The presence of heavy rain and hailstones in cumulo-nimbus clouds is a natural phenomenon which is of vital importance to people who fly in aircraft. With a suitable radar fitted in the nose of an aircraft, this precipitation can be detected and the information presented to the pilot so that he can steer the aircraft to avoid the dangerous turbulent conditions associated with cumulo-nimbus clouds. This is, of course, the basis of weather radars which have been used for many years, and are now regarded as more or less essential for civil aircraft.
‘The Impact of Radar on the Rule of the Road’
Authors: Kemp J. F.
Published: January 2010

Commander Clissold (19, 109) has produced a very well considered argument to demonstrate that the Steering and Sailing Rules are inadequate for present-day use and that in the future they are likely to fall well short of traffic requirements.

I agree entirely with this assessment and I agree in general with his proposed solution. His suggested Rule requires action to be taken by both parties to every encounter where there is risk of collision, and the most important objection to this is that it implies dual responsibility for manœuvre. This is something which many people consider highly undesirable despite the fact that it apparently succeeds in the case of Rule 18, and to proceed directly from the present Rules to Commander Clissold's Rules would, I believe, be too large a step to be generally acceptable.
The Pair Rule and the Collision Problem
Authors: García-Frías J.
Published: January 2010

In my recent paper I proposed a set of manœuvring rules intended to solve the operational aspect of the collision problem. These rules are simple, but they are different if the bearing is lesser or greater than 90°. The object of this paper is to present a simpler rule valid for every bearing between 0° and 180°.

The Pair Rule. Except for the singular situation of both vessels meeting head-on or head-to-stern, every encounter involving danger of collision is characterized by the fact that the heading of both vessels is on the same side of the sight line. Close-quarter situations also involve, in general, those standing head-on, except for some situations with the heading on opposite sides of the sight line when one or both of them heads close to this line. Consequently, the evading manœuvre must be such that both headings are on opposite sides of the sight line and opening enough to ensure a safe passing.
A Navigation Control Post for Automated Merchant Ships
Authors: Abramowski Czeslaw
Published: January 2010

The present trend in the automation of merchant ships may be compared with the situation which existed in aviation some thirty years ago when individual operators were developing their own ideas in navigation and flight programming, with little coordination and often a good deal of secrecy. In recent years some degree of automation has become usual in the design of new cargo vessels because of the need to reduce labour costs, and perhaps claims arising from accidents to personnel, as well as to increase efficiency of operation and reduce the margin of navigational error. But again there is the same lack of coordinated development and open discussion, in marked contrast to the planned development of the supersonic transport. In America, the U.S. Maritime Commission in cooperation with some of the instrument makers has carried out studies in ships' instrumentation, and also on cargo handling and machinery automation; but owners have remained aloof, following their own lines of development.