The purpose of this article is to describe the new tables, with the above title, which are shortly to be published by the U.S. Naval Oceanographic Office as H.O. Pub. No. 229.

Historical Survey. The most comprehensive tables designed for the application of the intercept method of plotting position lines in the practice of astronomical navigation at sea are the well-known Tables of Computed Altitude and Azimuth, originally published in the years 1936–1945 as H.O. Pub. No. 214 by the U.S. Navy Hydrographic Office (as it was then called). These are by no means the earliest of such tables in concept and objective, for Lord Kelvin, generally considered the father of modern navigation methods, expressed interest in tables from which solutions could be extracted direct; he recognized, however, that the tabulation of 903 × 603 or 157,464,000,000 solutions, which would be required to avoid interpolation, was quite impracticable.

The present trend in the automation of merchant ships may be compared with the situation which existed in aviation some thirty years ago when individual operators were developing their own ideas in navigation and flight programming, with little coordination and often a good deal of secrecy. In recent years some degree of automation has become usual in the design of new cargo vessels because of the need to reduce labour costs, and perhaps claims arising from accidents to personnel, as well as to increase efficiency of operation and reduce the margin of navigational error. But again there is the same lack of coordinated development and open discussion, in marked contrast to the planned development of the supersonic transport. In America, the U.S. Maritime Commission in cooperation with some of the instrument makers has carried out studies in ships' instrumentation, and also on cargo handling and machinery automation; but owners have remained aloof, following their own lines of development.

The remarkably successful development in recent years of inertial navigation systems suggests a reconsideration in this light of the phenomenon of animal navigation, the physiological basis of which has not been fully established. Some of the aspects of inertial navigation which may be particularly relevant to possible biological analogues are considered. Aspects of animal navigation and orientation that are particularly suggestive of inertial navigation are also treated. The physiology of the biological sensory mechanisms that could form the sensing elements of the biological inertial systems are outlined. Some suggestions are advanced for further investigations.

The Imposing structure of modern science and technology is a triumph of man's endeavour, and the story of its development, at last being closely investigated by the scientific historian, is gradually being unfolded. It is largely with the flowering of the practical mathematical arts, out of which modern science and technology have sprung, and with special reference to the English scientists, technologists, practitioners and teachers who collectively made this possible, that Professor Taylor writes in her latest book The Mathematical Practitioners of Hanoverian England.

Over the past few years, numerous papers have been written concerning various aspects of S.S.T. operations, the majority dealing with one or two facets. This short review considers those aspects which are of major importance when the S.S.T. is operated in non-optimum conditions and an attempt is made to indicate the relative cost penalty caused by the phenomena discussed, the performance in smooth standard conditions being taken as the datum. Little of the information presented is new and most of the points mentioned are considered in greater detail in the references. (Crown copyright, reproduced with the permission of H.M.S.O.)

The earlier papers in this series described the principles, and some of the techniques, which determine the approach to separation standards made at the Royal Aircraft Establishment. In this approach to the problems of estimating safe separation standards and specifying the quality of navigation needed, emphasis is laid on the observations of flying errors which occur in operational conditions. Dependence on theoretical assumptions is limited to the extent necessary to make usable ‘upper limit’ estimates of collision risk. Where critical assumptions are unavoidable, their nature and effects are shown.

This is the third article of a series of three describing the methods developed at the Royal Aircraft Establishment for costing the effect of air traffic control deviations in long range systems. The first two discussed the general principles of costing and their application to the current and future systems for subsonic aircraft over the North Atlantic. The present paper considers systems for the S.S.T.

The characteristics and mode of operation of the supersonic transport are untested, and it will operate at an altitude for which information is relatively scanty. This means that the results obtained for the cost penalties in a supersonic traffic system must be regarded as tentative. On the other hand, because we are considering traffic systems for aircraft at such an early stage of development, the situation can be analysed in a more fundamental way, with particular emphasis on the effect of the system on the aircraft design.

The input—output behaviour of a human operator in a control system is characterized by his ability to predict the course of a target based on past performance. With a stochastic signal or a more complicated system, however, prediction is necessarily imperfect and the operator's response lags behind the input. Mechanical prediction might therefore improve the human behaviour in a control system. The principles of the prediction display are described and two methods for mechanically calculated prediction are discussed: the model method and the extrapolation method.

The following discussion took place at an open meeting of the Technical Committee held in London on 8 December 1965. Captain Cotter, Extra-Master, is Senior Lecturer in Navigation at the Welsh College of Advanced Technology. Captain Wepster is Marine Manager of the Holland-America Line. Commander Leathes' contribution was prepared by the navigation section of H.M.S. Dryad and Wing Commander Rayson's contribution was presented on behalf of the Director of Navigation at the Ministry of Defence. Mr. Page is Chief Navigator of British United Airways.

The problem of determining longitude without reference to a timepiece is one which even today commands the interest of a number of mathematicians, astronomers and navigators. Having recently undertaken a crossing of the Atlantic in a small boat, I was particularly interested in Mr. Chichester's article and Mr. Sadler's comments in the January edition of this Journal.

The use of the visible horizon as a reference point for measuring the lunar distance from a celestial body is described in some of the older books on Nautical Astronomy. One method consists of observing the altitudes of the Moon and second body on opposite sides of the meridian and thence computing their respective hour angles. The sum of their hour angles is then equivalent to the difference in right ascensions of the two bodies. With this information, the lunar distance can readily be found and compared with tabulated or calculated lunar distances for given instants of G.M.T. to obtain the G.M.T. of observation. Mr. Chichester's variation of the method is certainly ingenious, and the need to compare lunar distances is thereby dispensed with. I cannot, however, see any reason why intervals as large as one hour between plots should be necessary: the overall size of the plot could well be reduced to one-sixth of the size, without loss of accuracy, by using times say 5 min. on each side of the ‘guessed at’ G.M.T.

I was very interested in the recent correspondence regarding a direction indicator to be fitted to ships and while I note the experiments now being carried out by our Dutch friends there are several points which must be borne in mind.

In the first place, whilst sophisticated arrangements like illuminated arrows may be very satisfactory from the operational point of view, this sort of apparatus is just one more piece of expensive equipment that the shipowner must provide and I foresee reluctance on his part if it is intended that this should come into general use.

Commander Clissold's article (Journal19, 109) like others before it seems to base the supposition that a new Rule is required on the idea that the collisions occur today because the present Rules are not good enough. I do not think that this contention is borne out by the evidence in cases of collision that come to Court; those are really the only ones on which conclusions should be based as very few people know what happened in the others. There is also a suggestion in his article that, before the days of radar, the Rules were adequate to prevent collisions happening. This is not so either; there were too many collisions in those days and they were caused by very much the same sort of behaviour as they are today. One should not, perhaps, think about the past success or failure of the Rules without remembering that it is not only the land which has become crowded in this century.

In the January 1966 edition of this Journal Captain Wylie has given a lucid summary of the factors involved in the presentation on radar displays of true and relative motion. He also stated a conclusion on the combinations of display and ancillary equipment which he considers best satisfy the requirements for use when plotting to avoid collision at sea. Whilst acknowledging with respect all the work he has done to clarify the issues raised on this important but contentious subject over a number of years, a number of us has found it impossible to agree with his latest findings. As these may influence opinion in the shipping industry, the Board of Trade, the Courts of Law and the radar manufacturing industry, both at official and unofficial levels, they should not go unchallenged. Our disagreement concerns the priorities defined for display equipment and the method to be used for plotting. There can be no disagreement on academic principles.