With the growth of public air transport, safety in the air is a matter of concern not just to those who design, manufacture and operate aircraft, but to the public at large. After an accident has occurred and an unfortunate chain of events leading to the accident is exposed, it may be easy to say ‘this accident should not have occurred’ or ‘would not have occurred if…’. Publication of annual totals brings forth informed and uninformed comment on the apparent decrease or increase in the accident rate relative to some criteria such as the number of passenger kilometres flown. The objective of this paper is to present a scientific account of the evidence on the relationship between navigation and air accidents and the implications of this evidence for those who are professionally concerned with air navigation. As will become evident, how-ever, there are factors operating which go much deeper than the technical aspects and appear to have their roots in human behaviour, not just of the individual but of organizations and society as a whole.

This paper, by the Deputy Managing Director and the Director of Operations of KLM Noordzee Helikopters BV., describes the operation of a 24-hour service now available for supplying pilots to ships entering the harbour of Rotterdam and for maintaining communications with North Sea oil rigs, with special reference to the unusual navigational problems involved. The paper, which was illustrated by a colour film, was presented at a meeting of the Institute held in London on 17 April 1974 with Captain V. A. M. Hunt, c.b.e. in the Chair.

Three aspects of the controllability of a ship may be distinguished:

(i) The intrinsic manœuvrability of the ship. Requirements can be stated in terms of the manœuvres the ship can perform by means of its own control devices.

(ii) The environmental boundaries. It can be ascertained whether the manœuvres as determined in item (i) compare with the area (for instance in a harbour) available for the manœuvre. Requirements can also relate to the manœuvrability of the ship in reaction to environmental disturbances and their compensation by means of the ship's control devices.

(iii) The human ability to perform the manœuvres of which the ship is technically capable in the area available.

In considering ships’ bridges, present and future, we must first look at the history of the bridge itself. In the days of sail it was necessary for the helmsman and Master to stand on the poop in order that they could watch the trim of the sails, and for the helmsman to get sufficient purchase on the wheel he had to stand up. With the introduction of steam it was necessary to stand as near as possible to the machinery so that orders could be passed by voice pipe and initially the ‘bridge’ was placed between the two paddle boxes. From here the quartermaster steered the ship and the Master passed orders to the engine-room by voice pipe or mechanical telegraph.

Ergonomics can mean the science of making work fit the worker or the study of man at work. This paper will be confined to the aspects of ergonomics affecting ship design, which include anatomy and physiology, anthropometry, and physiological and experimental psychology.

This paper falls roughly into three sections: the inter-relationship between economic forces, technological change and occupations, a brief history of navigation in occupational terms, and the present and future state of the occupation. The conclusions drawn may be open to discussion, since it presents a point of view and not a specific piece of research. It is restricted to the occupation of navigation in the Merchant Navy; naval and aircraft navigation appear to be very different as occupations.

The British Nautical Almanac was first published by Nevil Maskelyne, the Astronomer Royal, in 1766 for the year 1767 and the chief table in it was of lunar distances, which were tabulated at intervals of three hours to the nearest second of arc. On the bicentenary of its publication the theory and practice of lunar distance observation and reduction were reviewed in this Journal.

A basic concept for estimating the probability of collision for a ship navigating through a seaway with congested marine traffic can be derived by applying queuing theory to the relation between collision avoidance manœuvres and the traffic environment. Ships usually perform various ‘services’, such as altering course or collision avoidance, to other ships and geographical obstacles; the analogy of the collision avoidance system to queuing is that each arrival of another ship represents a ‘customer’ and each manœuvre of own ship corresponds to a ‘service’. A model for a collision-avoidance system was constructed analytically from queuing theory and expressed numerically, under assumptions based on traffic surveys and the statistical analysis of collision avoidance procedures at sea, in order to study the feasibilities of the model.

Keith Best's paper ‘Through the Proper Channels’ was published in the last number of the Journal. The following discussion of its principal proposals took place at an open session of the Technical Committee held in London on 6 May with Captain Maybourn in the Chair. Mr. Best is President of the British Section of the Societé des Ingéneurs Civils de France.

This paper surveys the present methods of pilotage and berthing, discusses some of the statistics of collision and grounding in confined waters, and suggests the development of shipborne automatic control devices to be used for the pilotage and berthing of large vessels. The proposed system, with its associated shore-based equipment, would carry out a similar function to the automatic landing devices fitted in aircraft, and would be part of an overall marine traffic control system. This system would enable large ships to be berthed automatically in reduced visibility and improve the safety of the movement of large ships in congested waters. The author lectures in the Department of Marine Electronics at Southampton College of Technology.

Captain Wylie's extensive and detailed criticisms of the Sailing and Steering Rules in the new Collision Regulations (Journal, 26, 365) were published in the January number of Navigation, the journal of the French Institute of Navigation, with an editorial note by Professor Hugon. The note and Captain Wyile's reply are given below.

The comments of Captain Maybourn on collision-avoidance systems in his paper ‘The Pay-off from Improved Navigational Aids’ (27, 133) prompt me to make a number of observations. What information, in principle, are we able to extract from a radar display ? This information will, of course, be degraded by the system errors, but that is another matter. Some of the following comments may appear trivial but it seems to me that they are of fundamental importance and escape sufficient emphasis.

In G. R. Spooner's interesting if not important article (27, 265), a situation was described wherein a risk of collision was created by basic non-adherence to the Rules. Firstly, the intention of the officer-of-the-watch to alter course to port was wrong, whilst that of the Master, substantially to alter course to starboard, was right. Secondly, the action of the non-burdened vessel was in error in as much as she should have stood on in anticipation of the burdened vessel making a decisive turn to starboard. The fact that at the precise moment of ordering this turn the other ship altered to port need not have necessarily prevented the burdened vessel from altering to starboard and ‘taking a turn out’—a procedure adopted in many such instances as that under discussion.

In the old Cunard Line the log-books on the passenger steamers had a K and an F column on the left-hand page of each opening. This was taken to mean, and in fact was so used, as Knots and Fractions (not fathoms as in W. E. May's article, p. 116, Vol. 27).

Each noon the junior third officer filled in the columns for the previous 24 hours, and each hour had the nautical miles and the fraction thereof expressed in cables which had been steamed, entered in the appropriate box. Thus the figures in the F column never exceeded 9.

Of immense importance to nautical astronomers are tables of trigonometrical functions. The history of these begins with the table of chords first suggested by Hipparchus two centuries before the beginning of the Christian Era. The earliest table of chords extant is that computed by Ptolemy (fl. c. 150 a.d.) whose table, true to the sexagesimal tradition, is based on the division of the radius of a circle into sixty parts. The first table of half-chords, or sines, is supposed to be of Indian origin and to date from the sixth century; but credit for being first to use a table of half-chords for solving spherical triangles belongs to the Arab mathematician Albategnius who flourished during the tenth century. The first printed table of sines, according to De Morgan, is a small work giving sines to each minute of arc from 0° to 90°, undated and unsigned but evidently published before 1500.