When, last year, you did me the honour of electing me your President you gave me the duty, and the privilege, of composing and delivering a Presidential Address. It does not lie within my abilities to make a grand survey of the present state of any great and important navigational development—such as might fittingly form the central theme of such an Address, and which has, in fact, been so admirably treated by my predecessors in this office. I have, however, been privileged to serve on the inner councils of the Institute since the earliest days of its conception, and feel that I may be in a position to take the Institute of Navigation itself as a central theme. I do so at this time particularly because the by-laws of the Institute quite rightly operate to ensure that no one person shall remain on the Council indefinitely and I must be the last to have such continuous service since the foundation. But there is a more cogent reason: the Institute was founded in the enthusiasm of the immediate post-war application of war-time navigational methods to civil use, and its precise role was deliberately left vague. It will be my object this afternoon to examine the extent to which the Institute is fulfilling its initial purpose and, on the basis of seven years' experience, how it can best play its part in the future.

On 26 November 1954 The Mathematical Practitioners of Tudor and Stuart England by E. G. R. Taylor was published for the Institute by Cambridge University Press. Dr. Derek Price, of the Whipple Museum of the History of Science at Cambridge, here describes the book for the Journal.

During the last twenty-five years there has been a revolution in writings on the history of science. Now, just as the profits are beginning to materialize, a second great change has occurred.

In modern air navigation, fuel consumption and cruise control present problems inseparable from those of pure navigation. Captain Majendie's paper, which was prepared for another purpose (but has not previously been published), is therefore of particular interest to navigators, because of the light it sheds on these related matters.

Instruments are to a very real extent the basic tools of both the pilot and navigator of a civil transport aircraft, and it is difficult to draw any clear line between their respective requirements. The following notes have been put together to try to give a survey of some of the most useful lines of development in this field. Clearly, such a survey must be in very general terms, but it is hoped that it may be of value in setting the various problems discussed into some sort of general perspective.

In its essence, navigation in ocean races is the same as navigation on any other voyage; the processes are the same and the drill is not very different. But it is a specialized thing and there are certain interesting problems which demand special solutions and special ways of doing things. To start with, the vessel is propelled by wind and one cannot, in the ordinary course of events, lay off one's mean course and steer it; the course will be continually varying, and the whole of the navigational problem is coloured by this fact. Again, navigation in ocean racing demands a much higher accuracy than navigation in an ordinary sailing vessel, where a landfall within five or perhaps even more miles in good visibility will be quite enough; the difference between spot-on and five miles away may well be the difference between winning an ocean race and otherwise.

Although an X-craft is a complete submarine in miniature, it does not fire torpedoes but carries two large mines which are dropped under the enemy ship at anchor in its harbour and time-fused to explode when the X-craft has retired to a safe distance. Each mine—or side-charge, as they are called—carries a heavy weight of explosive, but is fitted with internal buoyancy tanks so that its weight on the boat in water is negligible. Each side-charge is faired nicely to the hull to avoid catching nets or wires and well streamlined to keep its effect on the boat's performance to a minimum. In this article I will illustrate some of the navigational problems which arise in operating X-craft by giving an account of the attack we made on the Tirpitz in 1943

Most people know something about space ships nowadays, and probably think that navigation in space is quite a simple matter; at any rate, it is a subject that is glossed over very briefly in most books on the subject. In my view, space navigation is not a simple matter, and it has certainly not received the attention it deserves. Navigation on the Earth is easy, because of the one important fact that you are on the surface of the Earth. A couple of sights, measuring the angles from two stars down to the horizon, together with the azimuths of the stars and the distance from the centre of the Earth, will give an exact statement of position. But out in space there is no Earth, no horizon—in fact nothing whatever to use as a basis of measurement. Clearly then, two angles are not enough; a third one is needed, to give a sort of tripod of sights—two of the legs being anchored to two planets (or the Sun and a planet) because their positions in space at any time are known, and the distance between them can be used as a base-line. The solution of all the triangles involved is indeed a difficult problem, but there is also the impossibility of making three simultaneous observations. It might be thought that one could do as at sea and take one sight followed later by others, making allowance for the motion of the ship in the intervals. However, this involves the idea of dead reckoning, which, although a useful concept at sea, is quite impossible to apply in space, as the following example shows.

Recently two ships of the Holland-Amerika Line carried out speed trials, using the Decca system. With the permission of this company, which has shown great interest in this new method, the results of the trials are given in this paper. For comparison, some figures for trials on a measured mile are also given.

This paper was presented by Captain Wylie, in Boston in October 1954, at a meeting of the (U.S.) Radio Technical Commission for Marine Services, with whose kind permission it is here reproduced. The paper was one of a series which discussed whether further additions to radar could help reduce the number of collisions at sea. Captain Wylie made clear that the views he expressed were not necessarily those of the British shipping industry.

The preliminary to the Steering and Sailing Rules state: ‘Risk of collision can, when circumstances permit, be ascertained by carefully watching the compass bearing of an approaching vessel. If the bearing does not appreciably change, such risk shall be deemed to exist.’ What is to be taken as ‘appreciable’ when considering a change of bearing is not defined, but the watchkeeper at sea in clear weather has his accumulated experience to call upon and no difficulty is normally encountered in deciding on the degree of risk, except in the case of using radar in thick weather, when the watchkeeper has not the benefit of long experience. The purpose of this note is to consider the conditions under which the nearest approach can be estimated and to determine the accuracy of the estimate.

A New measure of time, Ephemeris Time, has recently been introduced by astronomers. The purpose of this short article is to explain briefly why this has been necessary and how it will affect navigation.

On 23 July 1954, the new Canadian Icebreaking Patrol Vessel H.M.C.S. Labrador (6000 tons) left Halifax, Nova Scotia, on her maiden voyage in support of the annual ship supply mission to the Canadian Arctic bases. In addition she carried out much hydrographic surveying and other scientific work, and subsequently withdrew to the westward, arriving at Esquimalt, British Columbia, on 27 September, thus becoming the first warship to complete the North-west Passage.

Beyond is a 43-foot auxiliary Bermudian cutter, specially designed and built for a voyage round the world. Between August 1952 and September 1954 she sailed some 30,000 miles, the track being shown on the chart (Fig. 1). From Lisbon to Auckland we were four aboard, but from Auckland back to England there were only my wife and myself. The following notes record the various methods of navigation.

The full value of A.P. 3270 (Sight Reduction Tables for Air Navigation, Vol. I, Selected Stars, H.M. Stationery Office) does not yet seem to have been fully appreciated by surface navigators. As well as increasing the speed with which sights can be reduced, the tables offer all the advantages of a star globe or planisphere in planning a series of sights. The navigator can thus concentrate on the most suitable stars for cut, magnitude and azimuth. Since observations can be planned for a time at dusk when the horizon is still firm and the star just visible through the telescope (or, at dawn, when the star is still visible and the horizon firm), a more accurate sextant altitude can be obtained.

I think that the impression which would be left by the Institute Working Party's Report (Journal, Vol. VII, p. 219) in the mind of any of the learned gentlemen of the Admiralty courts would be that a ship which did not keep a radar plot should be considered guilty of ‘neglect of any precaution’ under Article 29 of the Collision. Regulations, and this impression could lead to a miscarriage of justice.

Captain Wylie's note ‘Radar and the Compass Bearing’ (Journal, Vol. VII, p. 200) voices the objection to the ship's-head-up display because it gives bearings relative to the fore-and-aft line instead of to the axis of the compass card. This objection will not appear to be a very real one to anybody accustomed to using a dumb-card pelorus: a glance at the compass, or a word to the man at the wheel, will give the correction to be applied to the bearing in order to make it relative to the course by compass. If the ship is a degree right of her course we add a degree, if two degrees left we subtract two, and so on, before using the bearing. If plotting, the plot is a COURSE-UP plot, not a ship's-head-up plot. It is, in fact, a compass-datum plot with a more convenient orientation than the north-up which is so strongly advocated. It would appear to be mere hair-splitting to regard the corrected bearings as not being compass bearings within the meaning of the Steering and Sailing Rules since the important thing is whether or not the bearing is changing appreciably and not the number of degrees it contains. However, this objection, and that of the angular displacement of the plotted tracks of targets when course is altered, can both be completely negatived by using the course-up, gyro-stabilized display; the heading marker is set to zero when the ship is on her course and the gyro allowed to take care of yaw.

An illustration of a plotting aid having two bearing-scales was included in my note on ‘Radar and the Compass Bearing’ in Volume VII, No. 2, page 201. This instrument was a prototype from which that now illustrated as Fig. 1 has emerged.