bluuebunny/crossref_metadata_2025 huggingface dataset:
The Polaroid Procedure for Photographing Radar Screens
Authors: Wepster A.
Published: January 2010

In the July Journal (14, 362) Klerk and Steensma describe a new and ingenious method of radar plotting. The following comment, sent in at the invitation of the editor of the Journal, follows closely my remarks on a similar article in the Dutch review De Zee (December 1960).
The Automation of Ships' Navigation Systems
Authors: Clayton C. T. , Kurz Charles G.
Published: January 2010

The United States Maritime Administration recently published the results of a study, undertaken by the Norden Division of the United Aircraft Corporation, on automation and the operation of merchant ships. Mr. Clayton, the author of this important report, described the findings of this investigation, in so far as they affect navigation, to an Institute Meeting held in London on 16 November 1962. The paper, which is presented here, was written in association with Mr. Kurz of the U.S. Maritime Administration. It describes navigation systems for partially and fully automated vessels, and discusses the basic system requirements, accuracy and reliability criteria. A command philosophy for automated ships is developed, and finally a marine course computer, which is the first component of a partially automated navigating system already manufactured, is described. This is the first of several equipments being manufactured under contract to the Maritime Administration.

In early 1959 United Aircraft Corporation, led by its Norden Division as systems manager, undertook a company-sponsored study of the technical feasibility of operating merchant ships automatically. The results of this study were circulated throughout the industry. In April 1960 the Maritime Administration awarded a contract to Norden to study the economic and technical feasibility of automating merchant ships. The principal objective of the study was to develop a consistent series of planned, orderly, and reasonable steps towards completely automatic ship operation. The technical feasibility and economic advantage for each significant advance would be thoroughly established and then presented in a form suitable for selective application according to the particular requirements of individual ship operators.
The Navigation of a Communication Satellite
Authors: Clegg J. E.
Published: January 2010

The navigational aspects of the requirements for a medium altitude satellite communication system are discussed. Twelve satellites have to be injected into a circular equatorial orbit with very great precision. It is not practicable to navigate the launching vehicle accurately enough to obtain the correct orbit at first injection and the satellite itself has to be controlled and adjusted until finally it is correctly positioned with the right period.

The navigation of the third-stage rocket is discussed as this effects the limits of adjustment required for the satellite. Some error in period is necessary at injection in order to position the satellite correctly in orbit, in a reasonable time. A suitable tolerance on the period at injection is 3 minutes in 8 hours. This must be reduced, by fine adjustment of the satellite speed, to less than 30 milliseconds. Methods of measuring the orbital period to this accuracy are discussed.

When the 12 satellites are finally in orbit and equally spaced around the orbit they should remain for up to 5 years with the pattern substantially undisturbed.

This paper was presented at an Ordinary Meeting of the Institute held in London on 18 January.

The basis of navigation is the finding of present position and velocity so that the necessary action can be taken to guide the craft or vehicle to its destination.
High-level turbulence over Europe and the Mediterranean
Authors: Briggs J.
Published: January 2010

Aircrew reports of turbulence at heights between 20,000 and 40,000 ft. are analysed to show geographical and seasonal variation in incidence of turbulence. It is found that there is generally a summer minimum of turbulence and an autumn or winter maximum.

Reports of the occurrence or non-occurrence of turbulence have been made for the flights of Comet 4B aircraft of British European Airways. Although the assessment of the turbulence was no more than subjective it was thought that the uniform nature of the aircraft, operating over a large number of flight sectors in the European and Mediterranean areas, and the fact that ‘nil’ returns were also made, could give useful indications of the geographical and seasonal variation of the incidence of the high-level turbulence. An analysis of the reports, made during a period of twelve months, is presented here.
Service Area Calibration of Hyperbolic Navigation Systems
Authors: Sullivan Joseph E. , Porter William A.
Published: January 2010

It is well known that in low-frequency hyperbolic navigational systems the phase differences measured by the receiver do not correspond precisely to the hyperbolas on the plotting chart. This is largely because of variations in the terrain over which the waves are propagated. The system service area may be sampled so that the curve distortions can be ascertained at selected points. This article discusses how the whole service area can be calibrated, given a knowledge of the grid distortions at a sample of points. The mathematical treatment takes into account the correlation between the grid distortions at adjacent sampling points by using autocorrelation theory.

The degree to which fixing accuracy is improved by the proposed method of calibration is assessed against the background of an actual set of field measurements.

Mr. Sullivan is Head of the Applied Research Group of the Navigation and Guidance Laboratory at the Institute of Science and Technology. Dr. Porter is Assistant Professor of Electrical Engineering at The University of Michigan, and Head, Analytical Research Group of Navigation and Guidance Laboratory at the Institute of Science and Technology.

In low-frequency ground-wave navigation systems such as Loran-C and Decca, position information is determined from measurements of time and/or phase differences in signals received from several separately located transmitter stations. A pair of stations generates a family of hyperbolic lines which are the loci of points of constant time/phase difference. Two station pairs provide a grid of hyperbolas. By measurement of the time/phase difference between the signals from two transmitters, the receiver is located on a hyperbolic line. The same receiver is located on a second line by similar measurement which uses another pair of stations; the receiver is thus fixed specifically at the intersection of the two lines.
Radar Simulator Courses
Authors: Burger W. , Corbet A. G.
Published: January 2010

Some lessons and observations experienced during a series of radar simulator courses in the period of one year are listed below:

1. The practice of plotting is generally favoured by the students and they learn quickly how to determine which targets are of concern and should be plotted and which targets may be rejected. It has to be pointed out fairly often that recordings should be taken down in an orderly manner and that—besides the time, bearing and range of a target—the heading and speed (or log reading) of the observing vessel should be written down with each set of observations.
Training Sea Pilots on the Radar Simulator
Authors: Burger W.
Published: January 2010

The question of training pilots in the use of radar on a marine radar simulator was first brought up by pilots of the Swansea Pilotage Service. Their service is privately administered by the Swansea Pilotage Authority and, besides their ordinary pilot duties, each of the pilots has his own additional responsibilities, such as administrative and supervisory duties as members of the Pilotage Authority, the disbursement of pilotage earnings, the management of the Pilot Cutter Service, liaison with the dock authorities and towing companies in matters concerning the navigation of ships, pilot cutter crew training, navigational techniques, Swansea Bay surveys, &c. (There is even one pilot whose task it is to collect all the particulars of the latest navigational aids and so introduce them to his colleagues.) Altogether one is struck with a progressively-minded service consisting of members who want to make the best use of the modern aids which are being provided on board ships these days. Before pilots can enter the service they must be in possession of a Master Mariner's certificate F.G. (about one half of the pilots in the service have held command and candidates with Extra Master's certificates are on the waiting list).
The Perfection of the Gyro-Magnetic Compass
Authors: Treadwell R. J.
Published: January 2010

The pioneers of air navigation used a simple magnetic compass as a heading reference. At first boat or surveying compasses were used but these were not really satisfactory for use in aircraft, as engine vibration caused them to rotate. The first successful magnetic compass for aircraft use was the Creigh–Osborne compass which took to the air on 27 October 1909, in the British Army Aeroplane flown by the celebrated Col. S. F. Cody. In the years following and throughout World War I magnetic compasses based on this early work, with either horizontal or vertical cards, were widely used.
Harbour Radar Developments at Southampton
Authors: Andrew James
Published: January 2010

In this paper, a condensed version of an address to the Annual Assembly Meeting of the Radio Technical Commission for Marine Services held at Boston on 31 March 1964, where world-wide shore-based harbour radar surveillance and guidance systems were discussed, the Harbour Master of Southampton reviews some of the more recent developments of the Port Operation and Information Service at Southampton. Developments in the port itself are first briefly described and then some implications for Southampton of the Rochdale Report and the Harbours Bill are examined. After an account of some improvements in radar equipment used in the port, some new ideas now being investigated are described.
Meteorological Factors affecting Supersonic Transport
Authors: Scherhag R.
Published: January 2010

This paper was presented at the Eastbourne Convention in May 1964 and is based on data published by the author in recent issues of Meteor. Abh. Freie. Univ. Berlin.
Recommended Routes for Ships in Congested Waters
Authors: García-Frías J.
Published: January 2010

Captain A. F. Dickson's paper entitled ‘Recommended Routes for Ships in Congested Waters’ (Journal, 17, 217) suggests the introduction of a principle which I advocated in two previous papers, the second of which was presented at the Conferenza Intemazionale Sulla Disciplina dell ’uso del Radar, in Genoa, May 1957. Captain Dickson writes in his article:

It is therefore suggested that the measures to be taken should involve the application of one simple basic rule, that in all cases ships should keep to the starboard side of any channel and that traffic rounding a headland should be separated so that ships proceeding in opposite directions will have a port-to-port passing. In addition, wherever possible the different streams of traffic should be separated by a lane which would be a virtual no-man's-land between ships sailing in opposite directions. The lane might well be shown in colour and British Admiralty experience seems to indicate that purple is a good colour for chart usage, so the lane might be known as the “purple lane”.

In my works it was stated ‘Coastal radar navigation constitutes a very valuable means of making feasible an ordering of the natural traffic streams by regulating them according to the requirements of each area, following experience.
Bridge Lighting
Authors: Roberts C. J.
Published: January 2010

The fundamental necessities of efficient bridge and chartroom lighting, which matter appears to have been ignored even on many of the latest vessels, are the provision of:

1. Adequate illumination of all instruments in a uniform manner.

2. Efficient illumination of the chart.

3. A reduction of the high contrast of light values between chartroom and wheelhouse and the elimination of the sources of glare.

These three essentials can be combined to render the overall illumination of the navigating bridge efficient and practical, whether the ship has a separate chartroom and wheelhouse or the more modern chartroom and wheelhouse combined.

All bridge instruments, such as clocks, compasses, telegraphs and the numerous indicators, should be made to a uniform specification—all with ‘back’ or ‘edge’ illumination provided by red lamps. Where practicable these instruments should have black dials with white lettering. An extra refinement is to have the lettering painted with a luminous paint. Illuminating the instruments in this manner would also afford a certain amount of illumination to the otherwise dark navigating position. This would in turn tend to alleviate the high contrast of light between the chart area, which of necessity must be lit, and the total darkness outside.
I—The Control Characteristics of Hovercraft
Authors: Pennington W. A.
Published: January 2010

Any discussion on the navigational problems of hovercraft must obviously be closely associated with the control characteristics of the craft. Although these machines have been widely publicized as capable of operating over almost any terrain which is reasonably flat, it will be assumed that the present discussion is concerned primarily with operation over water.

The word hovercraft may be regarded as a generic term in the same category as aircraft, ship, motor vehicle &c., and practical examples are likely to take a variety of forms depending upon their particular application. Thus, the control characteristics and the way in which they affect the navigational problem are likely to vary, in degree at least, amongst the different types. Again, it must be realized that the hovercraft as a transport system is only at the beginning of a long development phase, and any remarks of a general nature which are made at this time must be read in that context. Even at this early stage, however, two distinct applications of the hovercraft principle, as applied to over-water transport machines, have emerged and it is important to appreciate the difference between them.
The Design of Reliable Digital Computers for Air Traffic Control
Authors: Cluley J. C.
Published: January 2010

A number of air traffic control authorities are now introducing electronic digital computers into air traffic control systems in order to speed operations and reduce the burden on controllers. These machines will initially be used for the routine clerical and data storage operations, but their full capabilities can only be used if they are given a much greater share of the control task and allowed to make logical decisions and intervene in the handling of the traffic. In such cases the computer will be performing a task that cannot be handed over to a human operator at a moment's notice in the event of a machine failure, and extreme reliability becomes probably the most important single attribute of a computer used in such a system.

Although computers of adequate speed and capacity are being produced for commercial and scientific uses, with reliabilities sufficient for these purposes, the frequency of faults and the time required for routine maintenance are both far too large to permit their full-time use in an air traffic control system. The reliabilities of typical components and systems are discussed in the following section.

1. The reliability of typical components and systems. The reports of a number of computer users suggest that ‘availabilities’ of 97–99 percent are readily attained, so that only 1–3 percent of the available working time is lost due to unscheduled maintenance.
Trials of a Television-type Radar Display for Traffic Control
Authors: Wikkenhauser G.
Published: January 2010

The work of the air traffic controller is necessarily closely interwoven with the instrumentation of the control system and it is difficult without actual operational studies to establish which tasks ought to be automatized and which left to the man. This paper describes tests carried out with existing instrumentation to convert a conventional radar display into a television-type display. The indication from the tests is that a 1000-line system would be needed. The paper was presented at the annual meeting of the German Navigation Society in Dusseldorf, 5–7 June 1962, and is printed with the kind permission of that body.
The Principles Underlying the Collision Regulations
Authors: Oudet L.
Published: January 2010

A great deal has been written, especially in the last few years, on the subject of collision at sea. The increase, however, in the speed of ships and in the density of traffic so magnifies the complexity of the problem that even closer and more earnest study is still called for. Three fields of inquiry demand our attention: technical advances, procedure, and the human factor. Of these, the widest and most promising might seem to be the first. Its importance is undeniable, and I am by no means the only one to have pointed out that with the new difficulties it raises it supplies also the appropriate solution. Even wider, however, and more complex is the field of human study; this covers both the others, for in this the final objective is to enable men to master what they have won for themselves, and this they cannot do—here we meet the familiar problems of philosophy, ethics and religion—unless they first learn to master themselves.

Compared with these two fields, the technical and the human, that of procedure must at first seem quite insignificant. Can one seriously imagine that there is in fact some new method of avoiding collisions, so abstruse that no one has yet been able to discover it? In my small book on the use of radar I wrote: ‘The Regulations envisage two ways of avoiding collision:

1. A movement carried out in concert with the other vessel.

2. A reduction of speed, if necessary to zero.
I—by P. L. Stride
Authors: Stride P. L.
Published: January 2010

Airborne weather radar equipment, carried for detection of meteorological phenomena, is now well established as a standard equipment for most transport aircraft, and is even being specified for the larger executive types. It may be useful, therefore, to review the basic factors which influence the value of the information obtained and the progress made with equipment designs during the last decade.

Turbulence on its own cannot be detected by radar. The radar defines areas in which some form of precipitation is occurring, i.e. heavy rain, hail, ice crystals or snow. Of these, the areas in which large water droplets fall as heavy rain on the ground or exist in suspension in the cloud are of most interest, since they are inevitably associated with convective cloud formations. All other information relating to the possibility of turbulence, ice formations, hail, &c., must be deduced by the observer from his knowledge of the mechanism of such meteorological phenomena. However, it is clear that the radar must display information on large droplet type clouds only. The presentation of small water droplet clouds not associated with convective processes would serve only to confuse the picture.

The theory of reflections from meteorological phenomena is dealt with very thoroughly in the literature and here only the main conclusions will be summarized to show how the characteristics of a radar set affect the information produced.
II—R. C. Alabaster
Authors: Alabaster R. C.
Published: January 2010

At present the rate of failure of a weather radar set is of the order of 1 failure in 50 sector flights. Probably the most reliable unit of the equipment is the scanner, which is fortunate because it is the most difficult unit to locate in an aircraft by virtue of its size and the need for uninterrupted forward scanning. With its present size the installation of two scanners is not feasible. In a piston-engined aircraft a radar failure when confronted by prolonged turbulent cloud conditions means no loss of aircraft range due to the adoption of optimum turbulence airspeed. The serviceability rate afforded by a single equipment is, therefore, acceptable since speed is not critical to performance. In a jet the inability to pick a way around turbulent cells if the radar fails, necessitates, by the adoption of optimum turbulence airspeed and altitude, a considerable shortening of range. It may be that in a supersonic aircraft, an unserviceable weather radar will make the flight abortive, since the ability to become supersonic will depend on smooth flying conditions.
True Motion in Relative Displays
Authors: Milwright A. L. P.
Published: January 2010

The system proposed by Manley (15, 172), to produce true motion on relative displays seems to suffer from two serious disadvantages which were not referred to. The first is that there would be a serious degradation in the resolution of the stored picture, since every time an original echo is rewritten into one of the Tenicon storage tubes the echo size would be increased both in range and bearing by the size of the beam spot. No doubt the full effect of this increase could be reduced by the introduction of pulse shaping circuits between the read-out and write-in points, but nevertheless the original small echo would be considerably increased in size if a number of read-out write-in operations were carried out as would be the case if the information was stored for a sufficiently long time to show true track. As an example, without applying any special pulse shaping techniques a small echo, two spot diameters long and one spot diameter wide, would be increased in size by 65 spot diameters if stored for 30 seconds (i.e. 10 scans of the aerial) and would be increased by 1890 spot diameters if stored for 3 minutes.

The second disadvantage is probably the more serious. Since any signal entering the system remains there until the stored information is cancelled, the effect of interference would be to flood the screen completely in a short space of time.
The Gestation and Birth of my Nautical Tables
Authors: Burton S. M.
Published: January 2010

The imaginary question I propose to answer in this address is—how does it come about that a person with such a very ordinary sort of intellect, and certainly with no particular flair for mathematics, should be the author, or nominal author, of such an imposing publication as a volume of nautical tables?

To build up the background to the story briefly let me explain that in my training ship days I received the impression that a ship's position was found by mathematical calculations. True, we knew that sextants and chronometers were necessary instruments in the scheme of things; but they only seemed to supply certain ingredients to the calculations that ultimately produced one of the components, latitude or longitude. It was when I was consigned to a stretch of service on the North Pacific in 1927 that, for something to do, I decided to try and improve my limited understanding of astronomical navigation. In the volume of Raper's Tables which I had always used there was an appendix by the Naval Instructor William Hall which explained what was then called by the Navy ‘The New Navigation’, and gave four-figure cosine-versine tables for the work. It was in reading, and re-reading, and thinking about Hall's marvellously lucid explanation of the St. Hilaire process that the light suddenly burst upon me.
II—The Azimuth Alignment
Authors: Whalley R.
Published: January 2010

Inertial navigation systems have become of great importance in the navigation of military aircraft and in recent years there has been a growing interest in their application to civil transports. A special problem arises with this class of equipment in that the axes require to be set before navigating and a particular difficulty arises with the azimuth. This involves penalties in special pre-flight routines or in extra cost and complexity of equipment which are of concern to the airline operator who is attempting to assess the usefulness of inertial techniques. The purpose of.this paper is to discuss the general principles on which azimuth alignment schemes can be based with reference to the likely penalties involved.

The paper is primarily concerned with systems where aircraft accelerations are measured by accelerometers mounted on a gyro stabilized platform and then integrated to obtain velocity. The velocity may be either used directly in a navigation computer or mixed first with velocity from another source, such as doppler radar, as described in Ref. 1. However, all dead reckoning systems require a knowledge of heading and in cases where a better accuracy is required than can be obtained by reference to the Earth's magnetic field, a low-drift gyroscope can be used as an azimuth memory. Some of the alignment schemes discussed would be applicable to these heading references as well as to stable platforms with accelerometers. With most inertial systems, alignment to the Earth's magnetic field would be made before fine alignment commenced.
The Navigator's Horizon
Authors: Chaplin J. M.
Published: January 2010

In his Presidential Address (Journal 16, 1) Dr. G. E. R. Deacon, C.B.E., F.R.S., says: ‘We have learnt from the Journal that one of the most frequent sources of error is a poor horizon, and recent (my italics) experiments by our American colleagues have shown that much can be gained by fitting a more powerful telescope in the sextant so that stars can be used while the horizon is better illuminated. They showed that it is better to look at the star directly and to make the horizon the reflected image.’

Dr. Deacon has been misled. In the ‘old’ Discovery from 1925 onwards (and before that in various surveying ships, whilst on passage), in which I was Navigating Officer, the horizon was always brought up to the star. A ‘sounding’ sextant also was always used. This is lighter than an ordinary observing sextant and mine had a large, aluminium telescope, of much greater power than the star telescope of an ordinary sextant, and with a very large object glass.

It was, however, graduated only to minutes of arc. To overcome this the altitude was pre-set for every contact to fixed intervals of, I think, 5′; this had the additional advantage that if the time of the middle contact agreed with the mean of the others it formed an excellent check on the accuracy of the sights and could be seen at a glance.
Polynesian and Micronesian Navigation Techniques
Authors: Lewis David
Published: January 2010

Dr. David Lewis has contributed two earlier papers to theJournalon Polynesian navigation: ‘Ara Moana’ in 1964, a theoretical examination of navigation methods, and ‘An experiment in Polynesian navigation’ in 1966, an account of his own voyage in the catamaranRehu-Moanafrom Tahiti to New Zealand. The present paper presents the result of further research which included voyages between the islands with Polynesian navigators. A version of this paper, which was presented at the Annual General Meeting of the Australian Institute of Navigation in Sydney on 10 and 11 October 1969, has been published inNavigation(Sydney).
The System Aboard Queen Elizabeth II
Authors: Warwick W. E.
Published: January 2010

The equipment fitted in Queen Elizabeth II was supplied by Aerospace through the International Marine Company. It consists of three units: an aerial, a two-channel receiver and a data processor. The receiver and data processor are housed in a single rack, the print-out machine stands beside the rack on its own pedestal. The aerial reposes on the truck; how-ever, as a result of experiments carried out on board, we are convinced that satisfactory reception of signals is obtained with the aerial sited directly on to the wheelhouse top. The rack and pedestal are located in a corner of the chartroom. Since fitting (Dec. 1968) the receiver has operated continuously, though we must own up to an occasional spot of bother with the processor. Nevertheless the vessel has only on one occasion entered port with the equipment out of use.
Manœuvre Demand Control for Aircraft
Authors: Shanks G. T.
Published: January 2010

The coverage of this paper, which was presented at an Ordinary Meeting of the Institute held in London on 18 March 1970, includes:

(1) A brief review of current aircraft flight control systems.

(2) A discussion of the benefits to be gained in terms of manual handling and full automatic pilot modes, in using feedback control techniques in the primary flight controls (Manœuvre Demand Control).

(3) A description of the work done on Manœuvre Demand Control at the Royal Aircraft Establishment, Farnborough, in the Avro 707C aircraft and in the Hunter Mk. 12 aircraft.
Metrication and the Nautical Mile
Authors: Turner R. J.
Published: January 2010

Although Admiral Ritchie does not agree, I still think that some significance does attach to the difference between the British Standard Nautical Mile and the International Mile. It is a matter of definition and is of vital importance to the young student beginning to study navigation. Unless basic definitions are clear and unambiguous continual difficulty arises which obscures practical considerations of the reliability of measurements that are made. Moreover, it is extremely unfortunate that the length of a minute of arc of a meridian was ever given the label ‘mile’—a standard of measurement of distance, or that anyone should ever have suggested measuring distance with a unit of variable length. The confusion that has been caused in the minds of student navigators over the years is enormous and the opportunity now exists for this source of confusion to be removed.
Anchor Dragging
Authors: Sharpey-Schafer J. M.
Published: January 2010

Anchor work is generally considered to be a question of seamanship rather than navigation; Commander Sharpey-Schafer's paper, which deals with a number of subjects only indirectly allied to navigation, is, however, presented here because what he has written will be of interest to so many navigators.
Some Refraction Measurements at Low Altitudes
Authors: Thom A.
Published: January 2010

It may be interesting to report some measurements of refraction which Professor A. N. Black and I made this winter. These were made on the setting Sun, and as the altitude of the observing station was 480.0 ft. it was possible to carry the observations down to the horizontal and, in fact, under clear conditions, to −20′.
Why not Graphical Sight Reduction?
Authors: Byerly Robert W.
Published: January 2010

Mr. J. B. Parker, in his review of Sight Reduction Tables for Air Navigation, published on pages 98–103 of Vol. VII of this Journal, states that the time required by him to resolve a three-star fix by means of A.P. 3270 is 10 minutes (p. 100). He comments on the ‘errors due to the plotted fix being a hundred or more miles behind the aircraft's position’ (p. 101). Later he says: ‘An accuracy of sight reduction of anything better than certainly 5 minutes of arc, and more logically 10 minutes of arc, will therefore be wasted on a navigator flying with present-day instruments in a fast modern aircraft in high latitudes’ (p. 102).
Radar and Collision at Sea
Authors: Tyrrell A. J. R.
Published: January 2010

Two practical measures might go a long way at the moment towards solving some of the questions raised by Captain F. J. Wylie in his paper (Vol. VI, p. 271) and discussed in the last number of the Journal (p. 202). The first is the provision of a suitable plotting device. It should not be too difficult to evolve a mechanism whereby a strip of transparent tracing material is passed across the face of the radar screen by means of two rollers (similar in operation to the echo-sounder paper passing over the plate in the modern sounding machine) in a direction parallel to the ship's course and at a speed representing that of the vessel and proportional to the scale of the radar picture in use. Plotting would be done by marking the ship's position and all other objects on the screen at short intervals and joining the consecutive positions of each object with a line. There would then be a continuous and up-to-date true plot of the area, which would be no more cluttered up with plotting than the actual area was with ships and objects.
Legal Aspects of Radar and Collision
Authors: Wylie F. J.
Published: January 2010

This article is based on a series of circulars compiled for and issued to shipowners and their ships. In the October number of this Journal, Captain Wylie dealt with the limitations of true-motion displays at slow speeds and of plotting when courses and speeds are varying. The present article groups relevant extracts from court cases and enquiries under the various points in the Collision Regulations. (Dates given refer to the court hearings.) Subsequently it discusses certain manoeuvres and radar practices and their effects on collision hazards.
Latitude by Maximum Altitude
Authors: Crosbie J. W.
Published: January 2010

Latitude by meridian altitude is one of the commonest position lines used in the Merchant Navy today, and the traditional method of obtaining it is to observe the Sun until it reaches maximum altitude, at which point it is said to dip. With the advent of power-driven vessels, however, this method became liable to an error of 5 minutes of arc, and as faster surface craft are developed it is reasonable to assume that the error could be even greater. This is because the rate of change of altitude of a body is related to the observer's speed over the Earth so that the body will dip either before or after meridian passage depending on whether the observer is moving towards or away from the geographical position of the Sun.
Kau Moala the Tongan Navigator
Authors: Hilder Brett
Published: January 2010

The whole question of Polynesian navigation is highly controversial. Dr. David Lewis's paper ‘Ara Moana: Stars of the Sea Road’, in the July issue of this journal, prompts me relate the story of Kau Moala in somewhat greater detail and to assess his achievements and motives, largely from his own account of his voyages.

Kau Moala was a Tongan Chief renowned for his epic feat of navigation which probably took place in the years just before 1800. The details come to us from a young English castaway named William Mariner, who spent several years in Tonga and knew Kau Moala personally. When Mariner got back to England his experiences were compiled by J. Martin and published by John Murray, London, in 1817. The work is generally known as ‘Mariner's Tonga’, the full title being An Account of the Natives of the Tonga Islands. The story of Kau Moala's famous Odyssey is given on pages 307–322 of volume I of the second edition, published in 1818. Mariner gives the Chief's name as Cow Mooaly.

The story starts with Kau Moala going from Tonga to Fiji to engage in some warlike adventures to enhance his prestige, as many another Tongan Chief had done before, and as several did later. After two years of fun and mischief he decided to return home, and set out in his large double canoe.
Accuracy Contours for Horizontal Angle Position Lines
Authors: Goodwin E. M. , Kemp J. F.
Published: January 2010

This paper describes a method of constructing accuracy contours for a position line obtained by observing the horizontal angle between two stations. An example is given using an estimate made, from experimental evidence, of the observational errors that are likely to occur when such angles are measured by sextant. A recent paper by Cotter described the historical development of this method of obtaining a position line.
Martelli' Tables
Authors: Cotter Charles H.
Published: January 2010

Captain S. T. L. Lecky, in his famous Wrinkles, wrote with derision in his reference to so-called ‘short-methods’. He warned his readers to ‘beware’ of these:

They generally only look short [wrote Lecky] because good care is taken to apply the various corrections beforehand, and the unsuspecting reader is deceived of this device.

As a case in point Lecky considered the ‘small but expensive pamphlet by Mr. Martelli’, to support his derogatory remarks:

When his so-called ‘short-method’ is overhauled and compared with Raper, we get the following startling result:—Martelli, 56 figures and five logarithms, against Raper's 59 figures and five logarithms, required to produce the same result. So that by the first method we have the enormous (!!!) gain of three figures. Furthermore Mr. Martelli's pamphlet contains several glaring errors which makes one rather dubious about the general correctness of the tables, although (for all the writer (Lecky) knows to the contrary) the mathematical principle of his method may be correct enough.
‘A Brief History of the Method of Fixing by Horizontal Angles’
Authors: Dickson J. , Gibson George A. , Cotter Charles H.
Published: January 2010

Readers of Captain Cotter's very interesting article ‘A Brief History of the Method of Fixing by Horizontal Angles’, may be interested to know that the possible use of the resection or three-point problem was appreciated by English mathematical practitioners of the seventeenth century.

Explanations have been given by John Collins, F.R.S. (1625–83), and Edmond Halley, F.R.S., Master and Commander, later Captain, Royal Navy and Astronomer Royal. It seems probable that Halley actually made some use of the principle when he charted the English Channel.

Dr. Angus Armitage and Dr. A. H. W. Robinson have explained Halley's method.
Air Traffic Control Separation Minima and Navigational Capability
Authors: White A.
Published: January 2010

During the past twenty-five years the aviation scene has progressed from one in which relatively small numbers of aircraft flew from point of origin to destination with the guidance afforded by very limited M/F range facilities and a great deal of individual navigational skill on the part of the operating crews. Air traffic control functioned only as a means of sorting out the order of take-off and landing. Moving forward to the present we see the already high density traffic serving the population centres of the world continuing to increase at a rate of around 10 per cent per annum. Both station referenced and self-contained navigational systems proliferate and control of traffic must be almost total if collision accidents are to be avoided. During the same time period aircraft speeds have increased threefold and necessitated a consequent improvement in the ability of the air traffic control service to react quickly and precisely to any conflict situations, either by detection in the strategic/planning case or resolution in the tactical frame by direct intervention before critical situations can develop.
Simplified Methods of Position Fixing Using Earth Satellites
Authors: Wright T. M. B.
Published: January 2010

The possibilities of using the measurement of the ranges to a pair of satellites to give an observer his position have been extensively studied, and expressions giving latitude and longitude have been derived. These since they involve powers of the fourth order are somewhat cumbersome, but given the appropriate computer on his craft an observer at a known distance from the centre of the Earth can obtain track data by measuring the ranges and continuously calculating his position. Alternatively, he may measure the incremental changes in these quantities from their value at the starting point which avoids (if a synchronous time or frequency technique is used) the necessity for continual two-way exchange of signals between the craft and the satellite, but the real-time solution of relatively complicated equations still has to be done.
Traffic Surveys in Japan
Authors: Yamaguchi Atsutoshi , Sakaki Shozo
Published: January 2010

For marine traffic engineering, traffic surveys are most important and provide the fundamental materials necessary for harbour and fairway design, traffic control planning, &c. Such surveys cover numerous items, the main subjects being traffic volume, speed, distribution of ships' tracks, origin and destination and type of cargo. Since we have to deal with many vessels, handled by people with varying temperaments, knowledge and ability, observations usually show a wide scatter; the object is often to find some formula or rule to explain the phenomena, and traffic surveys are therefore apt to prove both expensive and time consuming. When, for example, Yamaguchi and others conducted a year long observation on traffic in the Akashi Channel in 1963 at least two members of the team stood watch for 24 × 365 hours in a hillside cottage making both visual and radar observations. Since then the survey has been extended to more than ten other straits well known for difficulties in manœuvring.
The Analysis of Traffic Accidents
Authors: Fujii Yahei , Shiobara Reijiro
Published: January 2010

A marine traffic accident may be defined in the wider sense as a collision or stranding and in a narrow sense as a collision. Several reports are available on the causes of collisions and on the relation of collision frequency to such factors as location, weather and time; S. Fujii continuing Asai's work has shown that the ratio, R, between the number of vessels in collision and the number of vessels registered increases with the length of the vessel between perpendiculars. Shiobara gives a linear correlation between log R and log G with a slope of 0·5 and a correlation factor of 0·95, where G is the gross tonnage. In other words the collision frequency is proportional to L1.4. He further shows that R is almost proportional to L.
Controlling Shipping Along the North European Trade Axis
Authors: Lindsay D. J.
Published: January 2010

By the North European Trade Axis is meant the trade route from Ushant and Land's End, up the English Channel, through the Dover Strait fanning out to serve eastern England, the north coast of continental Europe and leading to the Baltic Basin. Recent events in this area have left a feeling that some form of tightening of control is not only desirable, but is rapidly becoming imperative. There is a basic conflict between the two forms of shipping using the area: the local users who use the area more or less constantly, and the long-distance traders, usually much larger, which arrive in the area for a brief stay after a prolonged period at sea, which has usually been in good weather conditions. Frequently these latter ships have a very poor notion of the hornet's nest into which they are steaming when they arrive. The net result is all too often the same: the local users, with familiarity breeding contempt, wander about as they see fit, with scant regard for routing or the regulations; all too often the big ships arrive from sea with navigating staffs who are too confused, sometimes too ignorant—and sometimes too terrified—to do much more than blunder forward in a straight line hoping for the best. Quite obviously this is not a total picture, and there are large numbers of ships which navigate perfectly competently, but the minority of those which do not seem to be rising rapidly, and show every sign of continuing to increase.
Terrain Clearance During Descent and Approach
Authors: Proctor J. D.
Published: January 2010

The purpose of the descent and approach is to move the aircraft from the cruise to final approach while keeping within the proper envelopes of speed, acceleration, rate of descent, adherence to A.T.C. clearances, avoidance of bad weather and clearance from terrain and obstructions and other visible aircraft. Man carries out this task, at least until the ILS glide slope is captured. The methods used are not as thorough as the programme an electronic computer would need for this task. Perhaps men prefer to use common sense, but perhaps a high level of safety can only be achieved with thorough rules.
II—A Navigation System Model
Authors: Mabuchi Shigeaki
Published: January 2010

Modern marine navigation is experiencing a more drastic change than ever before; automated systems are being introduced extensively in various parts of ships at various levels, inertial navigation systems are on the verge of introduction, the Navy Navigation Satellite system is now open for civilian use, and parallel with these developments modern data processing systems armed with electronic computers are being used at sea. In the processing of data, the application of modern statistical methods such as Kalman filtering should be noted.
The Extraction and Presentation of Collision Avoidance Data from Marine Radar
Authors: Shuffleton W. H.
Published: January 2010

Radar was fitted to merchant ships after the last war in the belief that, amongst other things, it would help to reduce collision casualties. However, by the early 1950s people were talking about ‘radar assisted collisions’ and today, in spite of improved radar equipment and training facilities, we read all too often of collisions between radar equipped ships. The question remains why such collisions occur; in part the answer lies in the fact that modern merchant ships have limited manpower so that the officer of the watch is often the only man on the bridge for long periods, and plotting ships' tracks from radar information is a time consuming business. The result is that, although radar provides the information required to avoid a collision, it is not in a form readily assimilated by the operator and incorrect interpretations can occur. The obvious solution is automatic extraction and processing of the radar information so that it can be presented to the operator in a form which will enable him to assess the situation rapidly. This would eliminate the tedious process of plotting, but retain the information normally obtained from a plot.
A Note on the Use of DCF for Marine Project Evaluation
Authors: McKenzie J. S.
Published: January 2010

King's observation that a false impression could be gained from long-term savings that do not take account of the time value of money is no doubt true if all aspects and factors of comparative projects are taken into account. However, he must think readers a little naive if he offers his Fig. 3 as a full interpretation of the possible savings from installing the various levels of shipborne automation explored in my recent article. An examination of Section 8 (Cost Equations) will show that the DCF technique was deliberately discarded in order to simplify the argument. In fact, there was an additional note—deleted by the Editor through lack of space—which observed that the appraisal could be based on the assumption that the discount rate was equal to the escalation rate of the savings occasioned by taking into account the rise in wages, victualling, &c. over the equivalent project period.
Some Thoughts on Marine Radar
Authors: Haines Gregory
Published: January 2010

The Man/machine interface. People who design motor cars also drive them, but whoever heard of a radar design engineer who also had a Master's ticket? Of course, the designers of marine instruments do go to sea occasionally, but not for longer than they can help; sea-time is apt to interfere with the weekend. So it happens that the people who make marine radars are rather remote from those who use them, and from the environment in which they work, the sea. The engineer might argue that no two seamen ever seem able to agree on what they want, so the easiest thing is to decide for them, and that, in any case, it is only a matter of ergonomics. On the other hand, it may be that the people who write books on ergonomics have not been to sea either. Radars are used in the dark, as are motor cars, but the darkness of the bridge is not the same as night driving.
The Pre-flight Handling of Inertial Navigation Systems
Authors: Brown K. R. , McKinlay W. H.
Published: January 2010

Operational experience to date has shown that while inertial navigators are more consistently accurate than some pessimists predicted, this accuracy is only achievable given correct pilot handling before take-off. The purpose of this paper is to examine some of the operational considerations involved in pre-flight handling and to indicate some engineering developments which promise to ease the pilot's task and thus contribute to the overall utility and accuracy of inertial navigation.