This article reports the discovery of two documents of considerable interest in the early history of navigation in England. When Henry VIII was planning to send ships of the royal fleet to Harderwijk in Guelderland in 1539, no pilot's book or chart of this part of the coast of northern Europe could be found in England. Therefore two experienced shipmasters, John Aborough of Devon and Richard Couche of Dover, were sent in haste to the Low Countries to make a survey of the coast and chart the route the king's ships would have to follow. Working with speed and secrecy, they compiled and brought back to the king a rutter giving sailing directions for Zeegat van Texel and the Zuider Zee and also a rough chart showing in detail the channels through the Haaks Banks, the entry to Marsdiep and the channel from thence to Enkhuizen. These two documents are the earliest original examples of such navigational directions drawn up by Englishmen which have so far been discovered. Both are reproduced in full and discussed in detail in this study.

Among the Marquess of Salisbury's family archives at Hatfield House is a document of great interest in the early history of navigation in England. It is a seaman's rutter giving directions for the navigation of Zeegat van Texel and the Zuider Zee which was compiled by two English shipmasters in 1539 on direct orders from King Henry VIII. A narrow roll of manuscript fashioned by roughly sewing four strips of parchment end to end, being not quite 6 in. wide and nearly 3½. long when fully opened out, this appears to be the earliest original English rutter which can be found today. It is true that the well-known set of fifteenth-century ‘Sailing Directions’ published by the Hakluyt Society in 1889 were compiled at an earlier date. But these have only survived in a copy transcribed by a professional scribe, William Ebesham, among a number of treatises on heraldry, chivalry and similar matters contained in a volume called the Great Book, part of the library of a country gentleman of East Anglia, Sir John Paston. The parchment roll at Hatfield would appear, therefore, to be the earliest example of an original English rutter which has yet been discovered.

The advantages of a standardized avoidance manoeuvre as distinct from a late collision avoidance manoeuvre are discussed with reference to passenger comfort. The general use of plan type displays suggests the possibility of having a standard manoeuvre based upon turning one aircraft on to a new heading.

An analysis of this manœuvre was undertaken in order to obtain data as to the closest permissible approach between pairs of aircraft on various collision courses. Results show that the permissible closure is smallest if the faster of the two aircraft is manœuvred, and that little is gained by changing the heading by more than 30°. The results of this type of analysis can assist also in the programming of the computer in a future automated A.T.C. system.

The paper proposes highly stable moored ocean platforms and a transatlantic submarine telephone cable to provide a reliable v.h.f. communication service and other A.T.C. facilities to civil aircraft on the main air routes across the North Atlantic. The main features of the platform and cable system are discussed and some idea of the time scale and costs is given.

The planning of facilities needed to enable future operations over the North Atlantic to accommodate reduced separation standards and to satisfy the specialized requirements associated with operating S.S.T. aircraft has emphasized the present unsatisfactory standard of communication services in the area.

During the Antarctic summer season of 1949 the Norwegian sealer Norsel, which had been chartered by the expedition, landed the Norwegian-British-Swedish Antarctic Expedition in Queen Maud Land in the Antarctic. In January 1951 the ship took down relief personnel and stores and for this trip the Admiralty, at the invitation of the planning committee, appointed the author as an observer. The decision to appoint a member of the navigation branch was made partly so that the techniques of ship handling and navigation in ice could be studied; and since the captain of Norsel, Captain Jakobsen, was extremely experienced in every aspect of ice navigation, a great deal of valuable information was acquired. The Institute had also suggested a number of astronomical observations that might usefully be made in polar areas and the Admiralty gave its approval for the observer to make them.

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.

A method of measuring wind variations along an aircraft glide path is described. The technique uses a ground-based pulsed doppler radar to measure the line of sight velocity of precipitation particles. At low angles of elevation this velocity is that of die horizontal wind component toward the radar.

Wind variations likely to be encountered by an aircraft as it lands or takes off from an airfield are estimated almost invariably from a nearby anemometer placed 10 m. above the ground. It is obvious that this wind is not fully representative of conditions at higher levels; however, winds other than near the ground are difficult to measure. This note describes a method of measuring the line of sight wind using a pulsed doppler radar and presents some observations of the wind variation along a path at an elevation of 3°, which is typical of the glide path of many aircraft. These winds are compared with those recorded by a nearby anemometer.

Various surveys have been carried out in narrow waters throughout the world and provide data on the traffic volume, traffic density, velocity distributions of ships, &c. Although these surveys certainly contribute to the safety of local navigation they do not give any information on traffic movements between terminal points in a marine traffic system. There are a few papers on voyage distribution based on traffic surveys, statistical reports or questionnaires to mariners and also a few based on radar observation, including one in Osaka Bay in Japan which was carried out by the traffic research group of the Kobe University of Mercantile Marine and Nautical Technical College.

In a book entitled The Black Tide, Richard Petrow presents a panoramic view of the events concerning the loss of the Torrey Canyon on the Seven Stones on 18 March 1967. The massive spillage of oil made it into a world disaster which called for a complete revision of many of the principles on which maritime transport is based. For seamen, however, the really important part comes before the spillage, when the ship stranded in apparently ideal navigational conditions. The Liberian Commission of Inquiry threw little light on the subject and criticism of the master does little to satisfy those with a professional knowledge of the sea. Here Commandant Oudet, relying heavily on the facts disclosed in Petrow's book, examines the circumstances of the disaster and comes out with strong criticisms of the Commission of Inquiry. If the subject is not exclusively navigational, it must be of great concern to all navigators.

Mr. Petrow's book contains what professionals need, even though the author recognizes that many questions must still remain unanswered. He has had access to the record of the Commission's investigations, but not to the report of the observer whose presence at the inquiry was secured by the British Government in spite of the owners' protests. While Mr. Petrow was able to spend four days interviewing Captain Rugiati, six months after the accident, he was unable to pursue his investigation by speaking with eye-witnesses, either those whose evidence was received by the Commission or those whom they failed to question.

The year 1932 was one which had no great apparent significance for navigators, and yet it saw the commencement of two new lines of research which today, after an interval of more than a quarter-of-a-century, promise important contributions to the safety of navigators both at sea and in the air.

The two lines of research were superficially quite unrelated, but fundamentally they relied upon the same principle—the detection of radiant energy emitted by objects solely as a result of their temperature. The first of these small beginnings was the discovery by K. G. Jansky that radio waves could be detected from extra-terrestrial sources: the second was the commencement by the U.S. Signal Corps Engineering Laboratories of an intensive study of infra-red devices with the object of obtaining night vision without illumination of the field of view.

From Jansky's discovery has sprung the whole science of radio astronomy, which has revolutionized our ideas about the universe, and brought in its wake, as one practical benefit, the radio sextant. From the work of the U.S. Signal Corps there resulted a number of very useful infra-red components, including the pneumatic detector, better known as the Golay cell.

In an earlier paper, the writer attempted a quantitative study of a flow-planning system for aircraft intending to fly across Europe. This paper aims to offer each aircraft a clearance giving a reasonable expectation that, throughout cruising flight at least, there will be no conflict with other traffic. Such a clearance is sometimes termed a ‘tube of flight’. Reference i assumed a pattern of traffic flying along rhumb lines, each flight having a starting position chosen at random in a region roughly the size of Europe. Flight was in a random direction and the flight path length was chosen at random from a plausible distribution.

Most professional navigators would agree that navigation could play a useful role in general education. How are teachers to be convinced of this and how are they to be persuaded that its introduction is desirable ? If navigation is to be introduced as an academic subject into the school curriculum we must endeavour to remove the mystique with which it is often surrounded and dispel the suggestion that it is an art rather than a science. The notion that successful sailormen must have a seafaring background has been proved wrong time and again; let us also dispense with the misconception that good navigators are born with a gift similar to that of a homing pigeon. Man has a natural instinct to explore and find his way; the purpose of navigation in education should be to exploit and develop this natural instinct to the full.

These two notes are the first of a series which will suggest to mariners the causes of collision at sea when radar is in use, by showing against each apparent cause an accumulation of court evidence and judgment, by isolating certain kinds of action which seem to have led to collision but have not been so regarded in every judgment and by examining certain judgments against a technically informed background.

In the articles which follow, a particular judgment is examined in the light of a more precise study of true motion as a direct source of intelligence at slow speeds, of plotting when courses and speeds are changing and of the suggestion that the Crossing Rules may be applied in fog after ‘ascertainment’.

The principal purposes of this introductory paper are to identify and describe the main aspects of marine traffic engineering, and to suggest ways in which traffic engineering principles and methods developed for land and air transport systems may be applied to marine problems. Traffic engineering is a relatively new branch of engineering science, but it was quickly and widely recognized as essential in ensuring that all forms of land and air transport operate safely and efficiently. However, although sea transport is a long established activity, it is only during the past few years that marine traffic engineering has begun to emerge as a separate aspect of this broader scientific discipline.

Since 1975 the Royal Netherlands Naval College has operated a bridge manoeuvring simulator for the training of naval officers and petty officers of the deck department. There is a strong relationship between training objectives and performance abilities of a simulator and the way the two match defines the cost effectiveness and the value of simulator training. The training objective being the result aimed at (for a professional watchkeeper) consists partially of a combination of training subjects (things to be learned at the simulator). During 1980 and 1981 R.Nl.N.C. conducted a survey on simulator training subjects by means of an inquiry amongst Royal Netherland's Navy and Merchant Navy officers, marine lecturers (all of Dutch origin) and members of the International Marine Simulator Forum (IMSF). The results form the subject of this note.

During recent years there has been significant development in several technologies which can contribute to the efficiency and safety of maritime traffic. The most important of these are accurate positioning systems (DGPS), digital data transmission/transponder technology, electronic chart systems (ECDIS), control of ships using electronic passage plans, and ship path prediction. With a widespread implementation of these new techniques, combined with advanced ship-shore and ship-ship data transfer, significant improvements can be achieved in traffic situation awareness both in a VTS and onboard. This paper describes the research carried out at VTT on VTS development, and especially gives an outline of new VTS functions using ship—shore and ship—ship data transfer.

Every collision situation implies the existence of a sector within which any course steered will lead to a dangerously close approach and a sector within which the danger of collision will be avoided. The definition of these sectors may be said to constitute the structural aspect of the collision problem. The appropriate manœuvre in a given situation constitutes the operational aspect. The structural aspect is fundamental to the problem itself, the operational aspect offers possible solutions. The Steering and Sailing Rules involve the structural aspect because this is the only basis for legal rules.

In proposing a Sector Rule for use with radar in conditions of bad visibility, it is intended to establish a structural basis for legislation. In its most general terms, the Sector Rule is based on the principle that if the radar echo of another ship is always at an angle to one's own course determined by the speeds of the two vessels, their distance apart and the safe passing distance, then one's course lies within the safe sector for collision avoidance.

This report summarizes a study of signals for indicating course alterations conducted by the Course Signal Committee of The Mercantile Marine Institute of Japan (President Captain Inazo Ara) as part of the 1995 project entitled ‘Research on Improving Course Signals etc’ sponsored by The Japan Foundation for Shipbuilding Advancement.

Although the use of bisectors to select the most probable position determined from astronomical observations is well known, the system seems to have received insufficient recognition in current navigational literature. In what follows an attempt is made to assess the problem practically.

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.