Since the last Institute meeting on the Admiralty chart in 1967 the compilation office, formerly at Cricklewood, has been moved to a new building at Taunton, alongside our printing works established there in 1940. Thus, except for a small office in Whitehall, which keeps in touch with the ever changing defence scene, the whole of our organization is now concentrated at Taunton, from where every week between 30,000 and 40,000 Admiralty charts are despatched, through our agents, to navigators in every part of the world.

As readers of the Institute's Journal will know, to mark the 21st anniversary of the Institute a special edition, entitled The Navigation Explosion was published. Papers published in this edition highlight the very rapid advances which have been made during those 21 years as a result of a happy marriage between the ancient art of navigation and modern science and technology.

By 1966 it was obvious, the Government having announced its intention for the country to go metric, that we had to think seriously of the metrication of Admiralty charts. With some 3500 navigational charts, many additional special charts, plotting sheets and other publications the task was unquestionably a formidable one, but it was decided that it could be done and a start should be made as early as possible.

It could be tackled in two ways, either by a gradual process, whereby charts would be converted as they came up for correction or where it was necessary to produce a new chart; this would mean slow progress and result in a haphazard geographical distribution. Alternatively such resources as were available could be concentrated in one area at a time and blocks of charts produced in metric units. This would avoid, to some extent, the difficulty to the mariner of having to jump about from fathoms and feet to metres and back again as he changed charts, and we eventually decided on this method—but in true British fashion are doing a bit of both.

In July 1963 the Hydrographic Department published a Notice to Mariners announcing the integration of charting arrangements between Great Britain, Australia and New Zealand.

Because of the historical associations, the Hydrographer of the Navy was the primary charting authority in Australian and New Zealand waters until comparatively recently. Local Hydrographic Offices were set up, and these, not unnaturally, began to turn out products strongly resembling British Admiralty charts, to such an extent in fact that we were clearly wasting effort in recompiling British charts which virtually duplicated the originals. Facsimile reproduction seemed an attractive proposition. Unfortunately the normal arrangements for use of another authority's charts, as laid down by the International Hydrographic Bureau, do not allow for facsimile reproduction but special agreements can get round this difficulty.

At the 9th International Hydrographic Conference in 1967 it was agreed to set up a Commission to study the constitution of an international set of charts, confining the study initially to charts on scale smaller than 1 in 1 million. This set should eventually enable all the members of the International Hydrographic Bureau (I.H.B.) to print in facsimile all such small-scale charts required for world-wide navigation in international waters. Among the factors which influenced this decision were:

(1) The duplication of charting which exists at present; as an example, six nations compile and publish a general chart of the Mediterranean, all with almost the same scale and limits.

(2) The large degree of standardization of chart symbols achieved by the work of the Bureau.

(3) The great and continuing increase in the work load of all the national hydrographic offices.

Some 7 years ago the North Sea Hydrographic Commission took up the question of deep draught routes in the North Sea and a basic pattern was selected and examined against existing hydrographic materials by the members of this Commission. In 1966 Shell International Marine produced a publication entitled The Channel and North Sea Routeing Folder. These more detailed routes together with the basic ones proposed by the Hydrographic Commission (although they are in no way official or necessarily accepted) form the basis of our present thinking on routes and planning of surveys in this area.

It was only a few years ago that a draught of 50 ft. was exceptional and it was generally considered that draughts were unlikely ever to exceed 60 ft. In fact draughts have increased rapidly ever since and for this reason, last year, we extended the limit to which we show soundings in fathoms and feet from 11 to 15 fin. in areas where deep-draught vessels could be expected to operate.

Although the Admiralty pilots have been regularly revised every 10 to 12 years as well as being kept corrected by supplement, there has been remarkably little change in the general style and content for over 100 years. As a major step has recently been taken to modernize and metricate the Admiralty chart, it was considered opportune to study the pilots at the same time. Therefore towards the end of 1968 a small committee was formed within the Hydrographic Department to review these books. The first action by the committee was to initiate some market research. All members of the Chart Users' Panel were invited to answer a questionnaire of twelve questions, but a few weeks later it was considered desirable to spread the research over a wider field and the same questions were sent out as a Notice to Mariners (No. 1737/68). The response was most encouraging and by the closing date at the end of December about 780 replies had been received and these have all been analysed. A few replies still come in, which puts the total at over 800$quite a good proportion of the regular users.

On 1 June 1967 routing was established in the Dover Strait. In the two years since then much experience has been gained and some of this has been reported already. The most significant fact to emerge so far is the sharp reduction in the number of accidents especially in relation to the amount of fog.

In the years 1961–7 before routing there was an average 14·3 collisions per annum, the lowest years being 1962 and 1965 with only 12 and the worst being 1961 with 23. In the first year since routing between 1 June 1967 and 31 May 1968 there were only 5 collisions, an all time low, and in the second year between 1 June 1968 and 31 May 1969 13 collisions with two after the 31 May 1969. Since most accidents in this area, but not as a whole, occur in fog it has long been established that a good measure of the safety record here is to examine the collisions per fog day. To do this in the Dover Strait, the amount of fog reported at the South Goodwin and Varne light vessels has been established from Trinity House and averaged to give an index for the Strait.

Tentative arrangements have now been made for the International Maritime Consultative Organization (Imco) to call an International Conference in 1972 to examine the international regulations for prevention of collision at sea and to make proposals for change where appropriate. It would therefore seem timely for members of the Institute with views on how the Collision Regulations might be amended to air these views so that all the aspects of the problem can be considered prior to the Revision Conference.

It would seem essential first to consider whether the rules as at present structured are broadly correct, which would indicate simply a review of each rule to see whether and to what extent amendments or improvements may be desirable, or alternatively whether some of the underlying basic premises on which the present rules are based are in need of revision, which would obviously mean very much more radical change. In the author's opinion the rules as now drafted do not seem to be correctly structured for modern navigation by the great bulk of ships on the high seas.

This study by the United States National Transportation Safety Board was undertaken to determine why ship collisions persist despite the use of radar and what recommendations could usefully be made to prevent collisions between radar-equipped vessels. The samples analysed cover the fiscal years 1963–7. An Appendix giving details of these collisions is omitted.

1. Introduction. The National Transportation Safety Board's review of the investigation of the collision between the S.S. Arizona and the M.V. Meiko Maru directed attention to collisions of vessels equipped with radar. In this case, the Masters of both vessels were navigating by radar to the exclusion of the Rules of the Road and the requirements of good seamanship, and neither was utilizing properly the radar to best advantage by plotting the relative motion of targets.

This paper outlines possible applications in the terminal area of an ILS based on hyperbolic geometry and correlation detection.

1. Introduction. A recent contribution to this Journal has surveyed the terminal area problem at London and outlined the research which is necessary to improve traffic handling capability. It was shown that contributions from many different development efforts will need to be integrated in order to achieve a worthwhile result. A fundamental aspect is that the problem of traffic congestion begins and ends at the runways and that the performance of the instrument landing system is of major importance. This paper will indicate how an approach and landing aid based on hyperbolic geometry and using correlation detection techniques can offer solutions to many of the known causes of traffic delay. The same principles can be used to integrate data links and monitoring into a complex which should be designed to aid the pilot as well as the controller.

The economic requirement for reductions in horizontal separation standards on high density oceanic routes such as the North Atlantic has motivated the search for a navigation and guidance system combining compatibility with foreseeable separation criteria while at the same time remaining cost effective. In this paper, by the Executive Vice-Chairman of the International Air Navigators' Council, an attempt is made from that point of view, to suggest various systems which are envisaged as meeting the most stringent requirements foreseen. Consideration is given to accuracy requirements, avionic hardware, and optimization of crew responsibilities based on airline experience derived over the past decade. Mr. Waldman is a navigator with Air Canada, but the views expressed are not necessarily those of the Air Canada Management.

1. Introduction. In the spring of 1965, an I.C.A.O. Special North Atlantic Regional Air Navigation Meeting (NAT/ RAN) approved by a margin often to two a reduction in nominal lateral separation from 120 n.m. to 90 n.m. in the ‘principal area’. (The ‘principal area’ of the NAT Region is the area delineated by Gander Oceanic, Lisboa Oceanic, New York Oceanic, Reykjavik, Shanwick Oceanic, and Sondrestrom, South of 700 North.)

The diagrams in the paper by Y. Namikawa and Y. Yamazaki with the above title (this Journal, 22, 169) are based on a fallacious argument. Since the distance run between bearings is one of the parameters a navigator must choose, it is useless to express the error as a multiple of it. Consequently their final recommendations are also invalid.

Instead, the error should be expressed as a multiple of the shortest distance off, a distance which is not affected by the pattern of observation chosen. The navigator must then choose the angles off the bow, or more correctly off the course made good, to obtain the best fix.

Commandant L. Oudet in his contribution ‘Lessons from a Needless Collision’ (Journal, 20, 30) may not have gone so far as to suggest that at no time ought either Tenacious or Placid to have altered course or speed then obtaining. Yet from his account this is plainly the case, a fact for which there must be some technical explanation, although he does not fully disclose it, saying rather, ‘We have not sought to teach but only to stimulate thought among Masters and their shipowners.’ No doubt others are not excluded. His pars. 2 & 3 give the facts in summary and the statement concerning the verdicts of Tenacious that ‘at 1330 she finds the bearing is steady’ plus some muttering about even worse than steady at 1340. This summary he later on amplifies slightly as to the facts:

(1) in par. 16, ‘between 1344 and 1349 … Placid made no (careful) observation.’

(2) in par. 18, ‘Placid did not detect this alteration (by Tenacious at 1340, from 130° to 160°).’

MR. J. A. Lee by his commentary (Journal, 22, 267) rightly suggests that instead of saying in my par. 1 (Journal, 21, 504), as I did after quoting Mr. Carr and Sq. Leader Scott, R.A.F. (Journal, 20, 406, sec. 2, par. 1) my words ‘—and from this deducing velocity and position of the vehicle,’ I could better have simply continued their words, ‘From this acceleration we can then, by successive mathematical integrations, deduce first velocity and secondly the displacement of the vehicle.’ Furthermore, it was superfluous and careless of me to add my quite worthless opinion as to soundness and virtue of expression on their part, but I comfort myself, and I hope also Mr. Lee, with the knowledge that there is no evidence that my opinions have ever previously had any effect whether for good or ill. To the extent, if any, that I can understand Mr. Lee's learned commentary, I believe I quite agree with him and am especially grateful for the clear definition given in his final sentence. If, however, an answer has been given to the question I raised as to the connection of Schuler's 1923 paper with inertial navigation, I am not presently aware of this.

The use of the Sun's shadow is a very old method for position finding. It is easy to adapt a small spirit level to produce a shadow on a millimetre scale which will give results of sufficient accuracy to add to the interest in learning to work out position lines for the Sun; less accurately for the Moon. Schools might find this useful for theoretical and practical classes.

The illustrations explain the principles involved and the constructional details. With practice it is fairly easy to set the style to the height necessary to give a clear shadow and to record its length to one tenth of a millimetre on the scale. To avoid errors of parallax in setting the style, the pinhole sight is held at the required height at the end of the spirit level opposite to the style while the latter's height is measured with the millimetre rule which should be held, vertical, about where the shadow is found to end on the scale.

The servicing of ships off Cape Town by helicopter with stores and spares is now established practice. In addition, test exercises are in progress with the Rotterdam Port Authorities to embark pilots by helicopter, and preliminary enquiries are under way for helicopter servicing in the Arabian Gulf.

Since the Institute is setting up a working party to consider the revision of the Collision Regulations, this may be a suitable time to raise the question of whether or not a vessel being serviced by helicopter or embarking a pilot by helicopter should be required to exhibit the day-time shapes prescribed in the Collision Regulations under Rule 4(c).

From exchange of correspondence in recent weeks with various interested parties, it is noticeable that there are differences of opinion concerning the necessity for helicopter serviced vessels to exhibit specific shapes, notably those required under Rule 4(c), and due to the non-existence of published official ruling, the following notes may be of general interest.

‘Inter-Relation of Temperature and Wind on the Route London-New York at 50 mb’ by A. F. Crossley, on page 151 of the April 1969 Journal: Figs 1 and 4 should be interchanged and on p. 156 , line 11, A is the true airspeed.