bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Underwater Sound on Marine Organisms
Authors: Suzuki H. , Hamada E. , Saito K. , Maniwa Y. , Shirai Y.
Published: November 2009

As sea traffic grows, so too does the problem of the acoustic pollution of fishing grounds. This paper describes the measurement and analysis of ship-produced underwater sounds and their effect on the behaviour of certain fishes. It would seem that their influence on marine organisms is a growing problem and should not be ignored by navigators, for the sounds produced by large or high-speed vessels, or even fishing boats, can frighten fish shoals or cause them to change their migration routes.

After a series of tests to measure and analyse the underwater sound, the output of submerged loud-speakers, either at sea or in an aquarium, was adjusted to ensure that the sound intensity near the fish was at the required level and the fish behaviour was carefully observed. For these experiments a hydrophone was connected to a pre-amplifier. A signal amplified by the pre-amplifier is attenuated before being sent to the main amplifier, the sound level being read directly on an indicator using the sound analysing character ‘C’. A tape recorder registers the sound signal in a flat response from 20 to 50 Hz to within 3 dB. A tracing recorder was also sometimes used and the two methods gave almost the same results.
P. V. H. Weems: A Personal Tribute
Authors: Sadler D. H.
Published: November 2009

The recent death of Philip Van Horn Weems, at the advanced age of 90, has removed from the field of navigation one of its most outstanding and colourful personalities. His contributions, made over a period of more than half a century, have ranged over almost every aspect of navigation: practising navigator, instrument inventor, pioneer of the GHA form of Nautical Almanac and of the first Air Almanac, introducer of the Star Altitude Curves, brilliant expositor (as his books so clearly demonstrate), successful business man who trained many thousand navigators through his training schools and correspondence courses – he devoted his whole life to navigation with boundless energy and contagious enthusiasm.

This is not the place to give the factual details of his life, or to put on record his many achievements, both inside and outside his professional career. Many of his most lasting and significant contributions to the practice of navigation, although so familiar to myself, can only be appreciated by a detailed study relative to the contemporary ‘state of the art’; Weems was, above all else, an innovator of ideas many of which were developed by others and which deserve a fuller and more technical treatment.

A brief summary of his career follows. Weems, left an orphan at an early age, had a hard life on the family farm in Tennessee, with little formal education.
Hong Kong Harbour as a Typhoon Haven
Authors: Malone D. J.
Published: November 2009

In the western North Pacific and the South China Sea the typhoon is one of the most fearsome elements a ship can encounter and one of the major decisions that must often be considered is whether to seek, or remain in, the shelter of a harbour or to take evasive action and ride out the storm at sea. With the many variables involved, such as topography, the different directions of approach of tropical cyclones, type of holding ground, size and shape of the ship, &c, it is often not possible to stamp a particular harbour as safe or unsafe. This paper deals with some of the many factors that a Master should consider when deciding to remain in, or sail from, Hong Kong on the approach of a typhoon.
Newton—A Man of His Times
Authors: Dyer G. C.
Published: November 2009

As one of many disciplines which involve the study of bodies and their motion, the science of navigation is heavily indebted to Sir Isaac Newton (1642–1727). Newton's outstanding contribution to science was his conception of the abstract idea of force and its mathematical formulation. This enabled the development of quantitative mechanics through the application of, for example, his Law of Inertia and his Law of Universal Gravitation. Whilst limitations in Newtonian physics have now been exposed at the level of sub-atomic particles moving close to the speed of light (Einsteinian physics), Newton's Laws remain the foundation stone to the solution of most everyday dynamical problems.
The Velocity Field: A New Concept in Navigation
Authors: Wright T. M. B.
Published: November 2009

The practical navigator relies on his ability to perform two fundamentally distinct operations: fixing his position and determining the course to steer. Guidance, in the sense that he receives (or generates within his craft) signals which continually define a vector coincident with his desired track, is not normally available to him.

Certain radio aids, notably the hyperbolic navigation systems, have however, frequently been used in the guidance role where the direction in which the signals can be particularly easily interpreted happens to coincide with the course to be steered. Thus, flying down a Decca lane is an acceptable operational technique which corresponds to making the aircraft follow the locus of constant range-difference to two points at known locations. It is not in principle necessary for the craft to perform the conversion from hyperbolic to Earth coordinates in order to do this.
The Use of Avionics DME Equipment for Marine Navigation
Authors: Canner W. H. P.
Published: November 2009

In recent years a great deal of research has been carried out in the twin fields of ship and aircraft navigational systems. The areas investigated have been closely related, but since 1945 the work has always been conducted independently, with virtually no cross-reference between the two industries. During the war years, however, this was not so and intensive research at that time resulted in some remarkable technical advances which related to both fields. The aids to navigation which then emerged have remained until recently absolutely fundamental and in marine navigation they have formed a platform of reliability, particularly the Decca Navigator system and radar. In aviation, airline competition on the transatlantic routes and the need for absolute safety has maintained a continuing process of evolution in the design of navigation and control systems. One such aid to emerge has been DME and, with the research and development complete, this is now a standard device for both military and civil operators throughout the world. A chain of ground beacons has been set up to cover the major world air routes and there are a considerable number of these beacons in the United Kingdom.
An Early Traffic Scheme for the English Channel
Authors: Cotter Charles H.
Published: November 2009

The anonymous author of a paper published in the November 1857 issue of The Nautical Magazine, introduced a novel philosophy in relation to the location of lighthouses. At the same time he discussed the proposition for a coastal traffic separation scheme for the English Channel — notorious then, as it still is, for its high incidence of collisions and groundings. The proposal was made just two years after Walter R. Jones of New York made his suggestion to Lieut. M. F. Maury of the United States Navy for an ocean traffic separation scheme which materialized in the form of Maury's ‘steam lanes’ for the North Atlantic.
Fuel Economies Effected by the use of FMS in an Advanced TMA
Authors: Attwooll Victor , Benoît André
Published: November 2009

The title of this paper could possibly be misleading in that it suggests that we already have a solution for a problem which is still open or at least a conclusion from an investigation which is still under way.

Accordingly, we should define straight away, subject to subsequent elaboration, (a) what we mean by an ‘advanced terminal area’, (b) what in such a context could be envisaged in terms of advantages for the aviation community, namely both the airspace users and the air traffic authorities, and finally (c) what new tools, both in the air and on the ground, would be desirable or essential in order to achieve a given degree of progress.
Integration of Advanced Displays, FMS, Speech Recognition and Data Link
Authors: Newbery R. R.
Published: November 2009

This paper outlines some of the results being achieved by the UK research programme on civil avionics which is based at RAE Bedford. Acknowledgments are therefore due to members of the civil avionics team and UK industry from whose work these examples are drawn, and not least to the Department of Trade and Industry who fund the programme.

No attempt is made to define ‘flight management systems’. The concept, originating in the complex outer loops of autopilots, has now come to include all the detail involved in managing the flight deck systems as well as planning and controlling the aircraft's progress from ramp to ramp. As this paper will hope to demonstrate, the concept is still growing.
FMS Airline Experience to date
Authors: Guest T. C. R.
Published: November 2009

The term flight management system (or FMCS, flight management computer system) is used to cover some equipment types which have been coming into service in recent years. In this context, it is taken to mean a system for handling horizontal and vertical navigation by various means (as distinct from purely performance management systems).

Such an FMS consists of a computer or computers fed by data from a variety of services, and outputting information and control signals. In horizontal navigation, inputs may be inertial sensors and/or ground-based radio navigation facilities. For performance optimization, data are fed from a number of aircraft systems. This type of system is capable of independently computing several parameters and ‘pooling’ their information to provide a ‘best estimate’. Cockpit information in INS configuration is confined to specific digital displays and data input is, in the main, manual and limited to numerics. FMS goes a number of stages further and provides ‘pre-loaded’ storage of navigational information, and the ability to gain access to this information through an alphanumeric keyboard. It also handles, either directly or through a thrust management computer, the vertical profile of the flight. This includes both climb and descent, and cruise control.
Vessel Traffic Services and The New Law of the Sea
Authors: Gold E.
Published: November 2009

In the history of navigation, the subject of Vessel Traffic Services (VTS) is a comparative newcomer. Nevertheless, it has and is generating interest, controversy and discussion analogous almost with the change from sail to steam or the advent of radar at sea. Interestingly though, much of the VTS debate has taken place within the industry itself—i.e. amongst the nautical professions, shipping companies and governmental marine regulatory agencies. This has resulted in a deservedly strong technical emphasis on the subject which, after all, is primarily concerned with marine safety. Legal questions have so far been sidelined or reduced to background interest. Legal problems relating to accident liability have been rarely discussed and when they were, have often been distorted.
Secondary Radar for Vessel Traffic Services
Authors: McGeoch Ian
Published: November 2009

The second half of the present century has witnessed the advent of intensified conflict of sea-use. The elements of this are well known: expanding international trade, carried in more numerous, often larger, and faster ships; the exploitation of oil and gas deposits under the sea bed; and always the fisheries, life-support of much of the still increasing population of the world.

The particular aspect of sea-use conflict which the establishment of Vessel Traffic Services (VTS) is intended to resolve is that arising from the concentration of shipping in the approaches to great ports, and in straits. The protagonists in this conflict are, on the one hand, any authority on shore which, with or without the sanction of international agreement, seeks to impose order upon the flow of vessel traffic, and on the other, the masters of vessels, each of whom is responsible ‘under God’ for the safe navigation of his ship. The pilot, as professional adviser to both the protagonists is now acquiring a new responsibility as ‘ honest broker’ between the ship master and the port authority. Indeed, it would accord with this role if the pilot were to be paid, in some proportion, by the port authority as well as by the shipowner. Be that as it may, since the establishment in 1948, at Liverpool, of the world's first port radar station, it could be said that experience has confirmed that by far the most important features of a Vessel Traffic Service are its radar coverage, which provides ‘the authority’ with an overview of all traffic in the area of responsibility; and the v.h.f. radio network for voice communication with the pilots, shipmasters, tugmasters and other individuals directly concerned with the operation of the port. It is a curious fact that, so far, there has been no concerted move to introduce the technological device required to enable the port operator to correlate an echo on his radar display with its corresponding identity and hence, radio call sign. It is the aim of this paper to compare the existing means of identification and recognition of radar contacts in a VTS with what is technically and economically feasible; to determine the operational requirement; and to set out the characteristics of a system which would meet the requirement.
Safety Standards for a 22-metre Deep-draught Route
Authors: van Riet J. A. , Kaspers J. , Buis B.
Published: November 2009

The design of a route through Dover Strait to Europoort for very large carriers (VLCs) with a draught of up to 22 metres is described. The results are compared with established international safety criteria. A number of subjects for further study by institutes of navigation are mentioned. Van Riet (DG Shipping and Maritime Affairs), Kaspers (Public Works, North Sea Directorate) and Buis (Hydrographic Service, Royal Navy) participated in this design process. The views expressed, however, are those of the authors and not necessarily those of their organizations.

Since 1974 deep-draught ships of up to 20·70 metres (68 feet) have been navigating the English Channel and the Dover Strait with destination Europoort in the Netherlands. To a lesser extent ships with these large draughts have been passing through the Strait with destinations in Scandinavian countries.
User Charges for Marine Aids to Navigation
Authors: Matthews N. F.
Published: November 2009

When considering user charges for the provision and maintenance of marine aids to navigation, it must be recognized that the basis on which they are calculated and levied is to a large extent due to historical accident. There is no internationally recognised system for levying these dues and every country has its own ideas as to how much money, if any, should be raised by this means.

User charges paid by shipping for marine aids to navigation normally fall into two categories. First there are national charges which go towards the running of the national lighthouse authority, either in whole, or in part. Such charges are referred to in this paper as ‘light dues’.
Navigation in the English Channel and the Southern North Sea
Authors: Paton J.
Published: November 2009

Rule 10 of the new Collision Regulations deals with the conduct of vessels in Imco adopted traffic separation schemes. In this paper, which was presented at a meeting of the Institute in London on 20 April 1977 with Commander R. B. Richardson, R.N. (ret.) in the Chair, Commander Paton, Hydrographic Adviser to the Department of Trade, discusses the traffic situation in the English Channel and Southern North Sea in the light of this Rule with particular emphasis on encounter situations at route junctions and the problems of crossing traffic.
Collision Avoidance Behaviour and Uncertainty
Authors: Riek Justus R.
Published: November 2009

When radar was first introduced to the merchant fleets of the world, many people felt that a practical solution to the collision avoidance problem had been found. However, a review of worldwide collision statistics of the past 20 years indicates that, in spite of the expanded use of radar, the over-all collision rate remains alarmingly high. Because of radar's less than perfect record for preventing ship collisions, development of various types of collision avoidance systems has taken place. The implied promise in this development is that the computer-aided radar will provide a lasting answer to the collision avoidance problem.
Statistics of Collisions at Sea
Authors: Cockcroft A. N.
Published: November 2009

In this paper, which was read at an Institute meeting in London on 11 February 1976 with Mrs. Mary Pera in the Chair, Captain Cockcroft examines the incidence of collisions in relation to the numbers and classes of ships at risk and their trends, pre-war and post-war. Total and partial losses are included and compared with other forms of loss, e.g. strandings.

In several previous papers statistics of marine collisions have been given for particular areas such as the Dover Strait, Western European rivers, the Baltic Sea and Japanese waters. This paper is concerned with worldwide statistics with particular reference to sea collisions. The information is mainly derived from the Statistical Tables published by Lloyd's Register of Shipping and from the casualty reports compiled by the Corporation of Lloyd's. Statistics of shipping casualties must obviously be related to the number or tonnage of vessels at risk; for insurance purposes loss ratios are usually expressed in terms of tonnage lost to tonnage afloat but navigators are more concerned with the number of casualties and number of vessels at risk in various categories.
The Early History of Great Circle Sailing
Authors: Cotter H.
Published: November 2009

The least spherical distance between two points on the surface of a sphere is that along the minor arc of the great circle on which the two points lie. It is an easy matter to demonstrate this using a cord stretched between two points on a small globe; noting that the circle whose plane coincides with that of the cord contains the centre of the sphere and that it is, therefore, a great circle. It is a little more difficult to prove the fact analytically. The practice of sailing along the shortest route on an ocean passage—sometimes known as ‘orthodromic’ as opposed to rhumbline or ‘loxodromic’ sailing—would require the course to be continually changed (except, of course, in cases in which the rhumb-line and great circle arc coincide). This would clearly be impossible; the term ‘approximate great circle sailing’ is sometimes used to describe the techniques of following a great circle route as closely as practicable.
A Marine Electrical Analog-type Dead Reckoning Computer
Authors: Gatehouse R. N. B.
Published: November 2009

The device described, which is in prototype form, accepts ship's speed from the Harrier electronic log and heading data from the Halcyon transmitting compass and continuously displays the north–south and east–west components of the water distance traversed from a starting position. It is a development of the Hadrian distance-offtrack computer which, with the Harrier log, has been described in a previous article published in this Journal.

The Sensors. Harrier is a through-hull impeller-type electronic log which records distance run in steps of 0·01 n.m. on an electromagnetic counter and indicates speed on a suitably calibrated milliammeter. Halcyon is a recent development, being a two-axis fluxgate transmitting compass which senses the Earth's magnetic field directly, thus avoiding the major problems associated with the use of pivoted magnetic systems in fast power vessels. The two rectilinear fluxgates are mutually perpendicular and are pendulously mounted with their axes in the horizontal plane. Viscous damping prevents their oscillating when subjected to vibration and shock. The outputs of the compass circuits are two d.c. analog signals which represent in magnitude and sign, the sine and cosine of the heading angle respectively.
Optoelectronic Displays
Authors: Ellis Brian
Published: November 2009

With the ever increasing information rates characteristic of modern electronic systems it is not surprising that display technology is one of the most vigorous fields of current research. A wide variety of phenomena is being exploited in order to produce displays suitable for a diversity of applications. This paper, which was presented at a meeting of the Institute in London on 17 December 1975, with Captain B. J. Calverb in the Chair, reviews recent developments in both emissive and passive displays, emphasizing the advantages of alternative types for particular applications.

Man's knowledge of the world in which he lives is steadily increasing and, compounded with a rapidly increasing capacity for communication, this leads to a need for new means of displaying the available information. The development of computers further increases this requirement since they make large quantities of information quickly accessible. It is to be expected that in many situations, where formerly the printed page or spoken word would at best have been the only practical possibilities, the advantages offered by modern electronic displays will increasingly be appreciated. In both civil and military applications it is clear for example that much information transmitted at present by letter could be better sent telegraphically, once suitably convenient displays are available; the need for ‘hard copy’ can be met where required. Considerable savings in time and convenience, not to mention paper, could clearly be made.
Automatic Radar Plotters: the Importance of the Future Position Control
Authors: Wylie F. J.
Published: November 2009

Anyone who has read articles by the present writer about automatic radar plotters but has not handled at sea one of those systems in which the vector lengths are time-correlated and have a fine (minute-by-minute) adjustment, might think that they tend to exaggerate its importance as an aid to realistic and rapid appraisal. I hope that the pictorial presentation which follows may serve to reverse such opinions even though, with still pictures, it is difficult to create the sense of a continuous and rapid series of brief manual movements and mental assessments.

Far from needing elimination, as suggested by Riggs (Journal, 28, 143), the rapidly extensible vectors lend apparent acceleration to the radar picture, which always changes so slowly on the PPI, and thus convey with verisimilitude a sense of the predicted movement of the entire complement of echoes in their proper mutual relationship. Further, in situations demanding particular care or perhaps a change of course or speed, they can be used to give a rapid forecast of the probable duration of the emergency.
The Role of Time in Navigation
Authors: Stratton A.
Published: November 2009

Time is so much a part of everyday experience that no thought is normally given to the meaning of the word. The scientific measurement of a quantity such as time, however, requires the definition of a gauge as a standard of measurement that is reasonably invariant to human experience and the creation of a measurement language capable of independent empirical reproduction so that one laboratory can share experience with another using only a written language to do so.

Time as a means of scientific measurement for navigation requires a further extension of this experience to independent reproduction on a moving craft.
Collision Avoidance Manoeuvres in Restricted Visibility
Authors: Barratt M. J.
Published: November 2009

Circumstances of collision. Over a fourteen-year period more than 80 per cent of all collisions in the Dover Strait occurred in reduced visibility. The majority of the ships concerned were carrying radar, so a possible inference is that the information available from this source is less effective than direct vision in successfully resolving close-quarters situations. The introduction of the Imco recommended routing scheme, the support measures mounted from the two sides of the Channel and sustained improvements in navigation have together led to a significant reduction in the number of collisions in poor visibility. However the risks, though reduced, remain higher than in good visibility.

The circumstances leading to collision are very rarely known reliably or in any detail, but such facts as are known can be helpful if treated with caution. Reference 1 gives details of manoeuvres preceding 47 collisions, nearly all in fog, where helm orders were noted in crew reports (Table 1). About three-quarters of these collisions (and of collisions as a whole) occurred when ships were on opposing courses, as defined by their ports of call.
Navigation and the Schools: I.
Authors: Anderson E. W.
Published: November 2009

On 29 October 1969, taking the chair at a Duke of Edinburgh Lecture, the great educator Lord Butler commented, ‘…in my view, it would do a great deal of good if navigation could be considered an educational subject’. Indeed, we know that by 1700 the discipline was being taught in ordinary schools in this country, and it is perhaps worth repeating Isaac Newton's remarks on the Christ's Hospital syllabus: ‘he that is able to argue nimbly and judiciously about figure, force and motion is never at rest until he gets over every rub’.

The inclusion of navigation in the curricula of schools during the 17th century was for financial rather than for educative reasons. In those days, the master of a ship was responsible for its navigation and invariably had a stake in the marine enterprise. Thus he might make a small fortune in a single voyage. By 1800, the introduction of the limited liability shipping company and the growth of marine insurance were beginning to relegate the captain to the status of a hired servant paid the minimum wage. Navigation rapidly disappeared from ordinary schools and was taught only in the specialized nautical establishments. Nevertheless, it is worth noting that today, the mariner, the submariner, the pilot and the astronaut have restored to the subject its original lustre and the yachting explosion has given the discipline a wide appeal.
Principles and Present Status
Authors: Cook G. E.
Published: November 2009

The Navstar Global Positioning System (GPS) is a satellite-based passive radio-navigation system under development by the US Department of Defense (DOD) and due for operational deployment in the late 1980s. Each satellite carries an atomic frequency standard and transmits L-band spread-spectrum signals whose carrier frequencies and code epochs are synchronized with the satellite clocks. A suitably equipped user may measure the arrival time and frequency of the signals from at least four satellites to obtain accurate three-dimensional position and velocity information and, as a by-product, an accurate ‘system’ time.
GPS for Marine Navigation
Authors: Maybourn R.
Published: November 2009

Seafaring has always been an occupation which exposes the seafarer to more than an ordinary degree of risk, and a significant part of that risk arises from his inability always to know his position with sufficient accuracy as and when needed. This lack of precision has always had a fundamental impact on the practice of navigation, the development of navigational aids, the production of charts and so forth, and to a much greater degree than is, perhaps, generally realized. As we are now approaching the time when a global capacity to fix position on demand and to a high degree of accuracy is becoming available it seems sensible that we should go back to first principles before forming a view as to its likely impact on future navigational practice.
Traffic Control in Separation Schemes
Authors: Filipowicz Włodzimierz
Published: November 2009

The paper deals with the formulation and analysis of the problem of ship's traffic control in separation schemes. The branch and bound procedure has been used for optimal solution of the problem. The proof for a possible computational process is given together with the results of a numerical example.

In view of the rapid development of the world merchant fleet the problem of safety at sea appears now as neither fully defined nor sufficiently analysed. Some measures and partial solutions to improve the safety of sea traffic have been suggested and implemented, e.g. in papers by Ciletti and Glas. As examples of such implementation one can mention traffic lanes, the calculation of separation-scheme optimal crossing angles, etc. In areas with heavy traffic where either natural constraints such as islands, submerged obstacles or traditional routes exist, all the separation lanes create sophisticated systems called traffic separation schemes. Many steps now being taken to improve safety of navigation are based essentially on traffic separation. Some innovations and improvements in designing the structures of the separation schemes must be taken into account. It seems that all such passive measures will be efficient up to natural limits connected with the magnitude of the traffic flow. In heavy traffic the author believes active control should be established.
Routing at Sea 1857–1977
Authors: Beattie J. H.
Published: November 2009

The Royal Institute of Navigation, with its counterparts in France and Germany, played a fundamental role in the introduction of traffic separation at sea, a role that is freely acknowledged in Imco's publications on the subject. J. H. Beattie, who was a member of the successive international working groups whose reports led to the introduction of routing, first of all in the Dover Strait and later throughout North West Europe, recounts the history of routing at sea, whose origins lay perhaps in the Great Lakes. A condensed version of this paper was presented at an Ordinary Meeting of the Institute on 14 December 1977, followed by Captain Emden's paper which is printed at page 203 with the ensuing discussion. Captain Maybourn was in the chair.
Lunar Methods For ‘Longitude Without Time’
Authors: Sadler D. H.
Published: November 2009

In 1966, in a note in the Forum entitled ‘Longitude without Time’, Francis Chichester described a method of determining longitude, or time (G.M.T.), from observations of the altitude of the Moon; and this gave rise to considerable interest. Recently a number of papers, of varying standards, have been published on the same subject; some, ignoring fundamental principles, have described techniques that are erroneous or misleading. Those principles, which have been well known for centuries, are here restated. In general, techniques of observation, calculation and plotting are not given; they are matters for the choice of the individual.
Fully-Automated, Pilot-Monitored Air Traffic Control
Authors: Ford R. L.
Published: November 2009

A recently completed preliminary long-term study of air traffic control systems in Europe1 suggests that traffic density is likely at least to double before the end of the century. The study also concludes that, apart from the problem of airport capacity, which was not considered, the existing ATC systems in Europe will not be able to cope with such an increase in traffic. There is therefore a need to consider methods of increasing the capacity of the European ATC system or providing a new system and, in view of the time required to effect significant changes to such systems, the task is becoming urgent.

Assumingthere is to be no deterioration insafety, theprime requirements for any proposed changes are economy and flexibility. Apart from its obvious intrinsic value, economy is necessary because there is an increasing trend towards recovering the total cost of ATC from the user. Higher charges are therefore likely to stultify the growth in air transport and an underlying assumption is that this would be undesirable. Flexibility is required because traffic forecasts so far into the future are likely to be in error and the system design must allow for this because there is likely to be some economic penalty if the forecast proves to be either too high or too low.
The Distribution Pattern of Omega Observations
Authors: Hiraiwa T.
Published: November 2009

This note on the distribution pattern of some Omega observations is based on a study of the phase differences observed at the Faculty of Fisheries at Hokkaido University (41° 48·4′N., 140° 43·3′E.). The A—D pair was investigated continuously, at half-hourly intervals, from i February 1974 to 31 January 1976, the A—C and C—D pairs from 1 January 1975 t o 31 December 197J and the A—H and D—H pairs from 1 January 1976 to 31 December 1976.
Collision Risks for Fixed Off-Shore Structures
Authors: Goodwin E. M. , Kemp J. F.
Published: November 2009

The presence of any structure in the sea is a potential hazard to shipping navigating in its vicinity. It is therefore of considerable interest both to mariners and to engineers placing structures such as oil platforms in the sea to try to assess the attendant risk of collision, with such a structure.

We have over a period of time attempted several methods of assessing these risks and it was felt important to link this with our work on marine traffic flows, as experience of the traffic patterns in the southern North Sea was a useful input to the study. Hence we considered an area in the southern North Sea, to the eastwards of the outer Thames Estuary as far as the Middlebank and between the parallels of 51° 08´N and 52° 15´N, since we wished to look at the offshore situation; the area is nowhere less than 3 miles from the coast.
Information Systems in Ports
Authors: Bradshaw M. R. , Jones K. D.
Published: November 2009

When in 1969 the specific task of scheduling shipping movements in and out of a tide-restricted port had been given as an exercise to a group of harbourmasters attending a symposium at UWIST, Cardiff, the varying methods employed and the apparently large workload involved indicated that a formal study of the problem would produce a more rational solution. The early part of the study, by K. D. Jones with the help of his assistant B. J. Moody, was to develop suitable computer programs to automate a scheduling process such that an ideal pre-movement plan could be arrived at, using as criteria the earliest movement times for given ship-draught and available water-depth.
A New Larboard Helm Rule for Power-driven Vessels
Authors: Hinsch Werner
Published: November 2009

The steering and sailing rules are changing with the development of available sources of information. This latest development is of special interest, as radar navigation has prompted a return to the principles of the ‘Larboard Helm Rule’ -if the compass bearing of an approaching vessel does not appreciably change, each of the vessels involved shall alter course so as to place herself to the right of the line of compass bearing o t the approaching vessel’.

This rule offered simple sailing instructions: each party to an encounter was required to take action. There was no stand-on vessel and no right of way. Our modern steering and sailing rules are based on the right of way of the vessel on the starboard side and this gives rise to difficulties unknown in the days of the larboard helm rule:

(i) There are two vessels on collision course, one large and slow-acting, the other small and manoeuvreable; the smaller vessel can easily take avoiding action. As, however, she is approaching from starboard she is the stand-on vessel. The large vessel, though restricted in her ability to manoeuvre is thus obliged to take avoiding action.

(ii) The officer on the bridge of the stand-on vessel recognizes risk of collision. The navigator on the bridge of the burdened vessel is distracted from his duty of keeping a proper look-out. Our existing rules require avoiding action on the part of the vessel that has not recognized the risk of collision.
The En Route Alternate and a Rational Basis for Contingency Fuel
Authors: Kimmins A. R.
Published: November 2009

When airline fuel is calculated before flight, ‘contingency fuel’ has been included either separately or in combination in various forms over the years. The primary calculation has always been the fuel required in expected conditions to fly to the destination and thence to a nominated alternate. The next is the provision, in the words of the Air Navigation Order, of a ‘safe margin of fuel’ for contingencies. For aircraft operated under an Air Operator's Certificate, CAP 360 specifies ‘an allowance for contingencies such as errors in forecast winds and temperatures, navigational errors and ATC restrictions on altitude and route’. Also, ‘45 minutes holding reserve’ is stated to be a normally overriding requirement. The wording of CAP 360 is, perhaps intentionally, not precise but is broadly in line with Annex 6 of the ICAO Chicago Convention which requires:

(i) a reserve ‘to provide for contingencies’ plus, for turbojet aircraft,

(ii) 30 minutes' low level holding, plus

(iii) an amount ‘to provide for the increased consumption on the occurrence of any of the potential contingencies specified…’
Simple Graphical Solutions of Spherical Triangles
Authors: Cotter Charles H.
Published: November 2009

A Device known as the Simplified Astro Platten (S.A.P.) is presently being marketed by the Bucks. Gear and Engineering Co. Ltd., of Middle Lane, Mount Pleasant, Aylesbury. It consists of a large rectangular plastic sheet some 29 in. by 16 in. on which are engraved two graduated semicircles with parallel diameters separated by a space of 2 inches. This sheet, on which pencil lines may be drawn and which can easily be cleaned when the lines are no longer required, is housed in a stiff plastic protective envelope. A mimeographed booklet of instructions includes examples and answers, for practice. There is no indication of the principles on which the device is based but the idea is certainly not new.
Automatic Radar Plotting Systems
Authors: Harrison A.
Published: November 2009

Following traditional naval tactics when outgunned, Captain Wylie laid a smoke screen in the January issue of the Journal and discussed what ‘imply’, ‘seem to think’ and ‘suggest’. Before my actual assertion becomes entirely lost to view may I repeat that a prediction of C.P.A., based only on radar data acquired in less than about three minutes, may be seriously in error. Precisely displayed, with no indication of the magnitude of the possible error, it can mislead. To say as he does that this danger is 'supposed' is certainly to beg the question, and supports my belief that the possible size of the error in C.P.A. is still not fully appreciated.
Developments in Marine Traffic Operations and Research
Authors: Wepster A.
Published: November 2009

Marine traffic can be defined as the combination of individual ship movements in a specified area and the ‘quality’ of marine traffic depends in the first place on the human and technical quality of the vessels participating. The second important situation is in the rules and regulations by which the individual vessels are bound. In some areas these two conditions seem inadequate to guarantee an acceptable level of marine traffic safety. An adequate yardstick by which to measure this level of safety is however still lacking.
A Decade of Navigation in the Antarctic
Authors: Le Pla P. , Draper J.
Published: November 2009

It has been the Government's policy to maintain an occasional British naval presence in the Antarctic, deploying the Royal Navy's Ice Patrol Ship south each year during the southern summer, when the ice and weather are slightly more clement. Ten years ago one of the authors was navigating officer in the Ice Patrol Ship H.M.S. Protector, the last remaining wartime netlayer, and extensively modified for her new role. A flight deck and hangar had been built over the net deck, special deck level tanks were added for the aviation fuel and eventually a new bow added, similar to the bow of the Blackwood class frigate. It was most effective and made the bridge area much less prone to spray, improving her performance in rough seas. Her original construction was flat bottomed with twin screws in tunnels separated by a skeg; the hangar made her act like a weather vane and when altering course it was usually necessary to apply opposite wheel 300 before the new course in order to steady her. She would roll on a wet sponge in dry dock but I became very attached to her, after all we celebrated our thirtieth birthdays within a fortnight of each other one glorious Antarctic day, and that is long service for a warship by modern standards. John Draper was navigating the present Ice Patrol Ship H.M.S. Endurance ten years later and it is interesting to compare navigational techniques and equipment then and now.
Determination of Mariners' Reaction Times
Authors: Curtis R. G.
Published: November 2009

This account of a recent simulator experiment at the City of London Polytechnic on encounter reaction times at sea will also be published as an internal National Maritime Institute report.

Two ships are said to have an encounter when they pass within a certain distance of one another, say half a mile. The encounter rate bears a relation to the collision rate in a given area of sea and consequently it is desirable to minimize the encounter rate. The effect of routing in sea areas with a high density of shipping has been to reduce the total number of encounters but to increase the number of overtakings. Thus the introduction of a routing scheme greatly increases the proportion of overtaking encounters in the main lanes. For example, the routing scheme in the Dover Strait (with I per cent of through rogues) has increased the proportion of potential overtaking encounters from 27 to 95 per cent.
The Current Situation
Authors: Haslam D. W.
Published: November 2009

As on previous occasions this Institute meeting was held to discuss different aspects of the Admiralty Chart as described by the Hydrographer of the Navy and his assistants. Earlier meetings had led to the formation of a Chart Users’ Panel, drawn largely from the Merchant Navy, and members of the panel were present on this occasion. The meeting described below, the fifth of this series, was held in London on 15 March 1978 with the Hydrographer, Rear Admiral D. W. Haslam, O.B.E., in the Chair.
An Arabian Sea Chart of the Middle Ages
Authors: Grosset-Grange H.
Published: November 2009

This study of fifteenth-century Arab sailing directions for the Indian Ocean is translated from a paper which was published in the July 1974 issue of Navigation, the Journal of the French Institute of Navigation. The spelling of modern place names has been assimilated to that of the Admiralty Charts and Sailing Directions but other Arabic names and terms have been left in the authors' approximate transliteration. Quotations from the Arabic texts are printed in italics.
The Navigation of Small Craft
Authors: Richey Michael
Published: November 2009

In principle there is of course no difference between the navigation of small and any other kind of craft at sea. In practice, though, the differences seem more apparent than the similarities—differences due to the conditions in which the navigator works and the greater vulnerability of small craft to the elements. I propose to offer some thoughts on three types of small craft navigation which reflect these differences. In terms of sail I concentrate on ocean racing because clearly whatever is effective in that demanding game will also satisfy less urgent requirements. I then refer to single-handed navigation which brings its own problems, and end up with some thoughts on high-speed navigation as exemplified in offshore powerboat racing.
‘The Dover Strait Information Service’
Authors: Parry R. H.
Published: November 2009

Captain R. K. Emden in his paper in the April 1975 issue of this Journal notes on page 135 that ‘the chief problem’ is ‘to identify by name and port of registry the radar “blip” deemed to be a contravening ship’, and that ‘the problem will be exacerbated as the Service expands’. In the discussion which followed Commander R. B. Richardson mentioned the m.f./d.f. receivers being used to assist ships to keep in lanes, and Captain Lusted mentioned investigations into the use of shore based v.h.f./d.f. for identifying ships.
Conflicts between Random Flights in a Given Area
Authors: Ratcliffe S. , Ford R. L.
Published: November 2009

This paper, which was presented at a meeting of the Institute in London on 2o May 1981, with Captain R. Maybourn in the Chair, describes some studies of the conflicts arising between a multiplicity of aircraft in straight-line flight through a volume of airspace. Topics include the effect of coercing traffic to fly fixed routes, the direction from which a threat can be expected and the choice of alerting criterion for a groundbased advisory service or an airborne collision-warning system. There are some analogies, perhaps, with marine traffic problems.

There exists, worldwide, a complex scheme for the segregation and control of various classes of air traffic. To fit into this scheme aircraft must make detours, horizontally and/or vertically, the cost of which in Europe alone must be at least £50M per annum. The cost of the rare failures in traffic management is higher still. To authors trained in electronic engineering it is therefore rather surprising that the published theory of air traffic management and control is still in a rather rudimentary form.
Recent Trends in Traffic Accidents in Japanese Waters
Authors: Fujii Y.
Published: November 2009

The number of ships involved in collisions in Japanese waters, excluding collisions with fixed or floating objects, increased rapidly in the 1960s, as can be seen in the statistics of the Marine Accidents Inquiry Commission: 1578 in 1955, 3604 in 1960, 6043 in 1965 and 7642 in 1970, while the increase in average tonnage resulted in numerous serious accidents. To cope with this situation, the Maritime Traffic Safety Law (MTSL) was enacted in 1973, defining eleven traffic routes in congested waters. The Tokyo Bay Traffic Advisory Centre was established in 1975 and started operation in 1977. The trend in the number of traffic accidents requiring assistance shows the effect of traffic management in reducing the number of accidents.
The Circumstances of Sea Collisions
Authors: Cockcroft A. N.
Published: November 2009

This paper, which was originally presented at the Fourth International Symposium on Vessel Traffic Services held in Bremen from 28 to 30 April 1981, here summarizes the results of an investigation into collisions world-wide, with particular emphasis on the circumstances of collisions associated with different types of encounter for conditions of both clear and restricted visibility.

Information relating to the circumstances of collisions is available from various sources but analysis of casualty information has usually been restricted to ships under one flag and been mainly applicable to accidents in restricted waters.
The Integrated Traffic Regulation Centre of Marseilles-Fos
Authors: Sicard R. , Chignard R.
Published: November 2009

This paper by the Harbour Master of Marseilles and his adviser on radio aids describes the system of traffic surveillance developed by the Port of Marseilles. The paper was originally presented at the Fourth International Symposium on Vessel Traffic Services held in Bremen from 28 to 30 April 1981.

The creation of an Integrated Traffic Regulation Centre (ITRC) was the solution chosen by the Port of Marseilles Authority to deal with the numerous traffic problems that had arisen in recent years in the Gulf of Fos due to the extremely rapid growth of the maritime traffic, especially oil tankers, converging on the Gulf which now totals over 80 million tonnes per year and the general tendency towards the construction and operation of very large ships, conspicuous in the development of oil tankers but now to a lesser extent in other categories of ship also.
A Table of Latitude Parts
Authors: Williams R.
Published: November 2009

D. H. Sadler has pointed out that the method I proposed in my paper (34, 247) can be improved, in his view, by the use of the formula

(1 + f) × distance = D.lat × sec(Co)

where the tabulation of Jean be found in his earlier paper (9, 371).