The wide range of interests of members of the Institute, combining as it does all aspects of marine and air navigation from the basic concepts through research, development, design, manufacture and marketing to practical operation, presents a most interesting challenge to the president in his address. This challenge is increased by the knowledge that this address will appear in the twenty-first birthday issue of the Journal in company with articles by eminent members of the Institute on developments in their own fields.

“Through art to science” was the theme of the second “Off the Beaten Track” programme of lectures for nautical schools and colleges. In the last twenty years navigation has changed in precisely that fashion. At the end of World War II, in spite of equipment developments, navigation remained an art, and this shines through the pages of our early Journals. Today the Journal proclaims that the art has become a science. “Sic transit gloria Astro!”

The twenty-first birthday of the Institute coincides very closely with that of commercial marine radar. Many merchant ships were fitted with naval radars between 1942 and 1945 but these bore little resemblance to the sets which would be needed for peaceful purposes.

Even before the war had ended, the United Kingdom Conference on Radio for Marine Transport (U.K.R.M.T.) was set up under the auspices of the Radio Board of the War Cabinet, to discuss the peacetime applications of the war developments. This conference led to the establishment of an Application Committee (R.A.M.N.A.C.) which kept the administration, the user and the manufacturer in touch. Immediately after the war, the Admiralty was in collaboration with the Ministry of Transport (M.O.T.) and the shipowners to arrange the supply of surplus 3-cm (Type 268) radar to the merchant navy, pending the design and production of commercial sets. At the same time the Admiralty Signal and Radar Establishment (A.S.R.E., now A.S.W.E.) was drawing up a specification1 to meet the needs of navigation and anti-collision. A prototype to this specification was demonstrated to all concerned in 1946.

Everyone now knows that radar has not fulfilled expectations as a means of preventing collision at sea, and that, because of this, its legal status is merely that of an aid to navigation. Nevertheless, everyone seems to feel that such a good technical instrument should enable ships to proceed safely in fog without reducing speed, and the fact that the collisions per fog day have increased by about thirty times in the fifteen years since radar became operational, shows that many mariners are in fact relying on it for collision avoidance. During these fifteen years, many papers have been published pointing out the dangers and giving advice, but in spite of this, the number of vessels involved in collision every year seems to have settled down to a constant figure of about 1700, or 7 per cent of the world fleet.

In 1945, when the end of hostilities restored freedom of commercial traffic, it seemed as though technical advances would enable it to acquire an ever increasing measure of safety. Soon, however, it became apparent that if ships were immune from the dangers of the past, it was only to meet other dangers which had been introduced by those very advances.

My first reaction on being invited by the Editor to contribute a ‘twenty-first birthday’ article on the above subject for the Journal was that there is little new to say. However, it is now 13 years since I prepared the presidential address on ‘The Place of Astronomy in Navigation’ (this Journal, 9, 1, 1956) and, apart from any other developments, space navigation has since become established as an operational science as well as a theoretical discipline. There have, in fact, been many developments and much progress in these 21 years; and, although these appear in the Journal and elsewhere mainly as gradual changes, a comparison over the whole interval reveals drastic changes, particularly in outlook and appreciation.

Position finding and hydrography—the plotting of coasts, channels and dangers to navigation—are the most obvious applications of science to the oceans, and they are the basis of well-established professions in which the use of accurate methods and the presentation of precise information are of paramount importance. Navigators can also make good use of knowledge of waves, tides and currents, but these are more variable in time and space, and, needing to be understood as well as charted, offer plenty of scope for academic study as well as a professional approach.

Although the merchant navy is one of the earliest users of navigation, it is today by no means the most spectacular user, especially in comparison with present-day hovercraft and the coming supersonic civil aircraft. This absence of the spectacular is, however, not due to lack of imagination or progressiveness, but stems from very natural circumstances. These circumstances are the relatively low-if not the lowest-transportation speed, the application of the laws of Archimedes to obtain the required carrying capacity, and the laws of economics which dictate a delicate balance between investments and net revenue.

‘Navigation demonstrateth how, by the shortest good way, by the aptest direction, and in the shortest time a sufficient ship between any two places may be conducted.’ To our Elizabethan forebears it was evident that the best way to conduct a ship was by the shortest passage of time which engendered least risk of catastrophe and avoided excessive wear and tear on ship, equipment and possibly passengers and crew. In the age of value-engineering and cost-effectiveness we are required to quantify these conflicting criteria. This is a matter of economics, which is concerned with applying the finite resources of mankind to the satisfaction of its infinite wants.

At the basic level scientific knowledge has now reached a stage at which sufficient is known to make possible almost any technological achievement in the field of navigation, if sufficient effort can be deployed in its solution. And at the project and engineering level refinements in control and planning have made possible the handling of vast and complex tasks within the necessary disciplines imposed by the available resources.

The last twenty-one years have seen some very striking advances in our knowledge of how animals can determine their location. In many cases we have learned that they have available a wider range of stimuli than ourselves for recognizing landmarks and for pilotage within their home area. Thus the associated senses of smell and taste are extraordinarily well developed in some species. The ability of the males of certain moths to detect the scent emitted by females at very considerable distances had long been known. More recently the extreme sensitivity, and selectivity, of fish to waterborne odours has led to an understanding of how they locate their home waters.

During the summer of 1968, to celebrate his twenty-first year with the Institute, the Executive Secretary sailed his boat Jester in the third single-handed transatlantic race, from Plymouth to Newport, Rhode Island. Of the 35 starters Jester was the last of the boats which completed the course. He here describes the reasons which led him to take a route which extends the distance of the course from 3000 to 5000 miles, and gives an account of the passage and of some of the problems of single-handed sailing.

Many readers of the Journal will have learned of the death, at the Hague on the 19 July 1968, of Jacobus Theodor Verstelle. He was aged 68. An authority of international standing on geodesy and hydrography, he was awarded the De Ruyter Medal in 1957 for ‘outstanding services in the fields of navigation and survey’ and became in 1965 an Officer of the Order of Oranje Nassau. He was elected to Fellowship of this Institute in 1955.

Mr. P. H. Sayers (this Journal, 21, 83) proposes a method of finding the observer's distance from a ship, buoy or lighthouse, the height of which is unknown, by measuring the angle between its waterline and the horizon, the angle thus found being reduced for the dip of the sea horizon for the height of eye. Table 1, an enlargement of the table which the author has used for some 15 years, gives the same information. It requires no correction for dip.