The problems of submarine navigation are entirely distinct from those encountered on the surface. Not only does the medium introduce a third dimension, which is not wholly analagous to that of the air since a definite limit is imposed on depth, but also a great many of the aids to surface navigation are either restricted in their use underwater, or are wholly inappropriate and will not function. The use of the principal aids to submarine navigation is briefly described in this paper, future developments being mentioned where possible. A more detailed examination is then made of the problems of underwater navigation, problems in the main that affect the accuracy of keeping a reliable dead reckoning. An account is also given of a gravity survey carried out in H.M. Submarine Talent, during which the author served as navigating officer. On this operation the requirement for position accuracy was high, and some of the methods used were of considerable interest. The survey also provided the opportunity for current and tidal-stream observations to be made at different depths and an account of these observations is given.

In a recent paper on shipborne radar the authors tried to analyze the mental approach of a master or pilot to the problem of handling his ship in a confined space when berthing in fog. The sense of loss that is caused by the absence of direct vision was referred to and various means by which confidence and control might be restored in these circumstances were considered. In that paper only the inadequacies of present-day shipborne radar in meeting these requirements were discussed. The approach to the problem can, however, be broadened to include the whole question of port operation in fog, and the present paper attempts to describe the general requirements and to consider in particular the role of shore-based radar and the manner in which the information obtained from radar or other aids should be presented to the master.

Because of the greater speed of modern aircraft and the increasing complexity of air-traffic systems, air navigation is changing and breaking away more surely from its marine counterpart. This divergence means that navigational equipment designed for marine navigation is becoming less and less suitable for use in the air, and the special needs of air navigation are slowly gaining recognition. This paper concerns air navigation charts; its aim is to show the shortcomings of the charts at present in use, and to suggest a specification for a new style of chart that will meet modern requirements.

At the beginning it is well to define exactly what is meant by the word ‘Chart’. In I.C.A.O. terminology it is widely defined and includes amongst other things maps; but maps are a special case and their use is limited to visual flight. In this paper, therefore, the word is used in its older sense of a sheet upon which the actual navigation is performed.

The Abridged Nautical Almanac in its revised form, for the year 1952, has now appeared. In place of right ascension and the familiar quantities E and R which were adopted in 1929, it tabulates Greenwich hour angle in arc for the Sun, Moon, planets and Aries, and sidereal hour angle (or versed ascension) for the stars.

Greenwich hourangle has been used in air almanacs for a number of years, and several surface almanacs have tabulated it as an alternative to right ascension; it is only recently, however, that it has been given exclusively in surface almanacs. Among the surface almanacs which tabulate G.H.A. at present are the American, Spanish, Argentine, Brazilian and Yugoslav.

The redesign of the Abridged Nautical Almanac has been under consideration for many years, but the change was delayed first by the war, and then by the desire to avoid a transitional period during which the new G.H.A. and E and R were given together; it was also decided to give as much notice of the proposed changes to users as possible. The design in substantially its present form was in fact accomplished in 1947, though the arrangement of the daily pages and much detailed work was carried out later.

The plan. During the spring and summer of 1950 three small British yachts sailed 15,000 miles in the open Atlantic, the object being to compete in the Bermuda race and then to race back across the Atlantic to Plymouth. Two of the craft, Cohoe and Samuel Pepys, were of under 5 tons displacement and the third, Mokoia, was very little bigger.

It is difficult to get satisfactory noon observations when the zenith distance is very small, because the Sun is rapidly changing in azimuth, the sextant must be swung through a wide arc of the horizon, and the Sun only dwells at the highest altitude for a very short period. To avoid these difficulties it is suggested that, instead of trying to measure the altitude of the Sun, one should measure its distance from a point on the horizon in a known azimuth. To make this measurement the Sun is brought down to the required point on the horizon, tilting the sextant as necessary; we shall distinguish this type of observation from the normal one, made with the sextant vertical, by calling the angle so obtained the horizon distance. At normal altitudes this method, however sound in theory, breaks down because one cannot measure the azimuth with sufficient accuracy. However, at very high altitudes the rate of change of horizon distance with change of azimuth of the point from which the distance is measured becomes so small that it is not necessary to know the azimuth with such precision. In fact, at a zenith distance of 1°, the largest we shall consider here, the greatest error caused by an error of 1° in the azimuth is l″, and for smaller zenith distances the maximum error is proportionately less.

Language holds many pitfalls for the unwary. A housewife picks up her iron, and so does the golfer: a butcher uses the steel and so does the soldier: a government nationalizes iron and steel. No wonder the foreigner makes ludicrous mistakes. And we in our turn, coming across an Italian book entitled Il Compasso da Navigare might be pardoned for supposing its subject-matter to be the navigating compass. This is not so. It is a learned and comprehensive treatise under the title belonging to the oldest surviving Sailing Directions for the Mediterranean Sea, and as the author, Bacchisio R. Motzo, clearly proves, such Directions were called a Compasso, and by a natural transference the same name was given to the sailing chart which was drawn to accompany the Directions. What we call a mariner's compass, or simply a compass, the Italians term Compasso-bussola or more usually just bussola. When English sailors began to use written Directions or ‘Pilots’ they called them Rutters (from the French Routier), while an alternative Italian name for a Compasso was Portolano, which also meant the accompanying chart.

As from 1953 the Air Almanac and the American Air Almanac will become a single publication, under the title of the Air Almanac. It will be produced jointly by H.M. Nautical Almanac Office of the Royal Greenwich Observatory, Herstmonceux, and the Nautical Almanac Office of the U.S. Naval Observatory in Washington, to meet the general requirements for air navigation in the United Kingdom, the United States and Canada. The Air Almanac will be printed and published separately in the United Kingdom and the United States but the two publications will otherwise be identical.

The early history of the Trinity House has been lost, partly in the mists of time, but mostly in the loss of records surrendered during the Civil War. The house itself has been destroyed by fire on three occasions, the first in the Great Fire of London, 1666; then in 1714 when a fire destroyed the Custom House, most of Water Lane where the Trinity House was situated and a part of Tower Street; and again in 1940 when fire, caused by incendiary bombs, destroyed nearly all the possessions of the corporation, some of which they had owned for upwards of 300 years. Such early records as they possessed, however, and their plate, which were stored elsewhere, have survived.

The corporation received its first charter, a copy of which is in their possession, from King Henry VIII in 1514, and the probability is that a Guild or Fellowship of some sort had been in existence for some time before, possibly under the same name, as a hall and almshouses were standing in Deptford in that year.

Summary of a paper presented by Dr. Bowen, as President of the Australian Institute of Navigation, to a meeting of the Institute held on 15 June 1951.

Accounts of the work described in this paper have been separately published, many of them in this Journal. The paper, therefore, restricts itself to giving a summary of this work, referring the reader to the appropriate literature for further study, and to pointing to some of the outstanding landmarks over the last few years.

The work referred to has been carried out by the Radiophysics Division of the Commonwealth Scientific and Industrial Research Organization in Australia and falls conveniently into two main headings, dealing with short-range aids to navigation and with air traffic control. It has been conducted for air navigation, but one at least of the navigation aids developed may find a useful application for maritime use.

This paper is an appreciation of the navigational problems encountered during a flight round the world in 1948, in a single-engined light aircraft. The route chosen (Fig. 2) covered nearly every type of flying weather in the world, from the perfect conditions of the Mediterranean in the summer to the severe climate of the Aleutian islands; navigation tests were provided by the overwater flights across the South China Sea (Hong Kong—Okinawa = 900 miles), the North Pacific (Chitose—Shemya = 1730 miles) and the North Atlantic.

The following method of drawing a position line from a celestial observation is suggested as a possible means of simplifying a small portion of the navigator's work. It avoids the use of azimuths, thereby simplifying chart work.

The method is based on a geometrical construction whereby the position line is determined from intercepts relating to two separate adjacent Assumed Positions; this construction may prove simpler than the present orthodox method, particularly as it does not involve the measurement of angles.

A condensed version of a paper presented to the Centre Beige de Navigation, Brussels, 9 January 1950.

The fact that the most expeditious route between two points on the Earth's surface is not necessarily a great circle is no new discovery. In the days of sailing ships courses were set to take maximum advantage of the wind; the trade winds were so called because they made the voyages of the trading ships possible. To a large extent they dictated the sea lanes and it was not until the arrival of the steamship that more direct routes across the oceans could be followed.

Summary of a paper presented to the Canadian Institute of Navigation at a meeting held in Montreal on 22 September 1950.

In 1946 and 1947 a great deal was learned about scope interpretation and the use of search radar as an aid to air navigation in the Canadian Arctic. New techniques, differing from those used during the war, when search radar was considered primarily as an aid to bombing and for pin-pointing, were developed and a great deal of information on interpreting the radar presentation of topography at different seasons was obtained. The use of search radar for navigation in the Arctic is described in this paper, which also gives information on the probable appearance of topographical detail on the display at different times of the year.

The British standard blind flying panel and its component instruments have for many years fulfilled a very useful purpose, but there are now a number of special operational requirements which this panel no longer meets. For instance, the probable general use of tail warning devices will make it necessary for the night fighter pilot to follow the violent evasive action of his quarry, and because of the higher speeds involved it is desirable that the pilot should be able to interpret his radar scopes himself rather than depend upon his navigator for directions.