The problem of underkeel clearance is not new; since time immemorial navigators have been concerned to know the minimum depth of water in which they can sail with a ship of given draught. Until quite recently, underkeel clearance requirements were determined almost entirely empirically, and in many cases the rule of thumb values used can be shown to be greater than the requirement of navigational safety would dictate.

In the years since the war the pattern of the oil industry has changed and very large ships are now commonly used to carry crude oil cargoes to a large number of ports around the world. It is obvious that use of these ships, with their deep draughts, has meant that a number of expensive dredging projects have been put in hand to provide adequate access to the ports served. Continuing escalation in size means this will probably continue.

Since the inauguration of the B.O.A.C. Return Ferry Service, the principles of pressure pattern flying have been followed on the North Atlantic as regards flight planning. In co-operation with the forecaster the practice developed of working out a number of flight plans to achieve the shortest possible flight time, and eventually it became possible to select the most favourable route with a reasonable degree of precision.

The advent of the radar altimeter furthered development of the pressure position line theory which I believe was first propounded by R.A.E., Farnborough, and has since been elaborately garnished and enthusiastically tested by our American friends during recent years. The words ‘altimetry’ and ‘aerologation’ have been added to our generally common language to cover flight techniques that might perhaps be more simply described as ‘pressure comparison navigation.’

The paper is divided into two parts. The development of ship-borne compasses is reviewed in Part I; in this section some of the difficulties due to bad siting, &c., are mentioned and certain solutions such as the use of repeating compasses and improved methods of correction are described. Part II surveys the development of the aircraft compass and shows how its phases of development have corresponded to those of the marine compass. Some recent forms of aircraft compass and methods of development are also described.

Waves, tides and ocean currents might not be expected to produce electric currents, but by moving water, as a conductor, through the Earth's magnetic field they do in fact produce measurable voltages and flows of electricity. Young, Gerrard and Jevons, who made the first detailed study of this phenomenon, thought it conceivable that measurements of electric potential gradient might be used to estimate the drift of a ship at sea, and Von Arx showed how indications from electrodes towed behind the Research Vessel Atlantis were used to keep her on a direct course from Bermuda to Woods Hole, across the Gulf Stream. In recent years the method has been used extensively in studies of ocean currents and more ships might use it if the necessary equipment were readily available.

At the present day European ATC is exercised by a multiplicity of more-or-less autonomous control centres. ‘Flow Regulation’ is used roughly to match traffic demand to the capacity of the en-route ATC and of the destination airport. The ATC authority at the point of departure for a remote destination cannot however give any guarantee that the pilot will be able to follow his chosen trajectory. The filed flight plan and the departure clearance have been described as a ‘licence to get into the sky and see what happens’.

For some years the principal maritime nations have provided sea-going and future Masters and mates with some form of radar simulator training. These training courses, although differing in duration, subject material, training method and technique, had one common aim: to familiarize responsible sea-going personnel with radar as an instrument. They taught understanding of the various instrument controls, picture or display interpretation, plotting and anti-collision tactics based on the existing international Rules of the Road and Admiralty Court jurisprudence: and all this for open-sea conditions where the Master is sole master of the situation and with no outside adviser at his disposal. Many Masters and mates have followed these very necessary and useful training courses and many more will undoubtedly follow, for nobody should today go to sea in a responsible position as Master or officer of the watch without such training. Recently, pilot authorities have started to send their pilots to the same courses and again this is a step in the right direction.

A recent survey by Burger and Corbet (Welsh Institute of Technology) has furthermore shown that those trained do not seem to obtain full advantage of the acquired knowledge, once they are back in actual practice. This fact plus the fast technical advances in electronics and consequently new radar techniques should eventually lead to the institution of refresher courses.

Following the Amoco Cadiz disaster in 1978 proposals were put forward, and ultimately accepted by IMCO, for a revision of the traffic separation schemes off Ushant and the Casquets, the broad effect of which was to keep large tankers (and those carrying hazardous cargoes) further off the French coast. The modifications came in for some criticism and recent Anglo-French proposals have now secured IMCO agreement. Prior to that a purely United Kingdom working group sought to formulate a comprehensive and continuous routing scheme for the whole English Channel.

Captain Cockcroft who, as an observer for IAIN at IMCO and as RIN representative on the UK working group on Channel Routing, has played a leading part in these discussions, here describes some of the problems and considers issues raised by concepts such as ‘areas to be avoided’, and finally, within the context of traffic separation in straits, proposes alterations to the Collision Regulations which govern the crossing of traffic lanes and the use of inshore traffic zones.

The weather is rarely out of the news. Weather can be hazardous at times almost anywhere on Earth, and the media are always keen to report dramatic events. On the global scene, weather, climate and the environment are issues of great international public concern at present because of the likely implications of increases of greenhouse gases in the atmosphere. The contributions of the meteorologist to the understanding of this global problem are increasingly recognized, as is the progress which has been made in the accuracy of day-to-day forecasts. This paper provides a brief résumé of our present ability to model and forecast the behaviour of the global atmosphere and the ocean surface, and also demonstrates how these models are applied to the practical problems of operational ship-routeing by the UK Meteorological Office. It is worth remembering that it was the very high incidence of losses at sea in the 1850s which brought about the establishment of the UK's first meteorological service.

In this paper, presented by the International Air Navigators Council, and written by its Executive Vice Chairman, the navigation of the S.S.T. is considered from the practising navigator's point of view. Extrapolating from present procedures the conclusion is drawn that navigation system verification should continue to be the responsibility of flight-deck management, that self-contained D.R. systems should be monitored by an externally referenced aid, that raw navigational data should continue to be available to the flight crew and finally that simplicity and reliability in navigation systems should be preferred to finite accuracy.

Consideration of an environment in which operational data and experience are limited to the military is a difficult assignment at the best of times. In order to discuss, with some degree of intelligence, the long-range navigation system considered desirable in the supersonic environment, we have relied mainly on the process of extrapolation using existing data and operational ‘know how’ to formulate practical guidelines.

This paper, which will be presented for discussion at the Eastbourne tripartite conference, 12–14 May, examines the efforts made in recent years to improve marine radar in three respects, namely greater expressiveness of the display, simplification of measurement and computation, and increased reliability. Particular developments in each of these directions are discussed, their effectiveness and shortcomings mentioned and the conclusion reached that there is still a long way to go.

Operational research has been developed and introduced into air transportation problems since the late 1940s, mainly in the U.K. and the U.S.A., and simulation techniques have also been used for designing or evaluating air traffic control systems. Some data on the actual operations are needed for carrying out these studies. The data on the time and motion of taxiing aircraft, especially jet aircraft, were collected at Tokyo International Airport (TIA) in 1975 and 1976 and the relation between average taxi speed and taxi distance was stated on the basis of the observed data. In this paper, a theoretical method for estimating the average taxi speed of departing aircraft is considered, using simplified models, and the results are compared with the empirical data.

When measurements and observations are made using a radar simulator, the researcher assumes that mariners behave in the same way, whether they are handling a simulator or a real ship. This paper, which was presented at an Ordinary Meeting of the Institute held in London on 22 April 1980, investigates whether this is a reasonable assumption.

This paper is concerned with the effect on airline operation of the introduction of inertial equipment, from the engineering viewpoint. It is difficult to avoid entirely all operational considerations but the main object here is to stress the economic and engineering aspects arising from the use of this equipment.

Over the past few years several papers have been written based on the results of surveys of marine traffic in different parts of the world. The general knowledge of the overall picture of the behaviour of ships at sea has increased considerably but there are still many aspects which need to be explored. One of the main fields of interest of the Marine Traffic Research Unit at the City of London Polytechnic is the use that mariners make of available sea room. For any particular area the navigational difficulties are going to vary considerably in situations where ships enter the area at different points, travelling indifferent directions, from situations in which the ships tend to keep to a number of defined routes through the area. If ships do tend to adopt a routing structure through an area, the next question of interest is how wide the various routes are, given no physical limitations for their width. The behaviour patterns may vary for different types of ship, and speed is another variable which may affect the situation. Answers to all these questions would be needed if one wanted to analyse the efficiency and safety aspects of marine traffic in an area.

The Institute’s NAV 88 Conference, with the above title, was held in London from 22 to 24 March. It included nearly 40 papers concerned broadly with the way ahead for radionavigation in Europe. The Jull proceedings of the Conference are available on application to the Director, price £30 (plus £3 p & p) for Members (£60 plus p & p for non-Members). A summary of the Conference is presented below, and this is followed by one of the Conference papers which describes a rationalization of radionavigation in the USA.

In this paper, which was presented at an Institute meeting, held in Britannic House in London on 1 December 1970, the Chief Marine Superintendent of the BP Tanker Company examines the problems of operating large merchant vessels in the Arctic and describes the experience gained from the two voyages of S.S. Manhattan through the North-West Passage. The chair was taken by the President, Rear Admiral G. S. Ritchie, C.B., D.S.C, Hydrographer of the Navy.

With most tele-operated robots the operator's only feedback is the view from an onboard camera. Live video lets the operator observe the robot's immediate surroundings but does not establish the orientation or whereabouts of the robot in its environment. An additional plot of the robot's trajectory would be helpful for the operator and is sometimes provided, based on GPS. However, indoors where GPS is unavailable, tracking has to rely on dead-reckoning, which is too inaccurate to be useful. Our proposed TelOpTrak method corrects dead-reckoning errors even when only odometry and a low-cost (and thus, high-drift) MEMS-class gyro are available on the robot. TelOpTrak corrects gyro drift by exploiting the structured nature of most buildings, but without having to directly sense building features. This paper explains the TelOpTrak method and provides comprehensive experimental results.

Earlier versions of this paper (Borenstein et al., 2010a), (Borenstein et al., 2010b) were presented at two conferences. The main difference between the earlier conference papers and the present manuscript is that the latter is more comprehensive, more up-to-date, and it presents an entirely new set of experimental results, including results of a live demonstration at the 2010 Robotics Rodeo event at Ft. Benning, USA.

Radar transponders and radar target enhancers have been in use in a variety of applications for many years. Perhaps the most widely-known applications of radar transponders are in Identification Friend or Foe (IFF) and its civilian counterpart, secondary surveillance radar for air traffic control, and as racons in marine navigation and, most recently, as Search And Rescue Transponders (SART) in the Global Marine Distress and Safety System (GMDSS).