It is probable that within the next ten years marine transport technologists will be faced with some difficult choices in relation to ship propulsion for an era of high fuel prices. They will have to consider (i) the continuation of conventional power driven vessels with greatly improved engines, or low speed operations; (2) the development of high speed nuclear powered ships; and, (3) the use of sail. Whether the latter will be adopted to any significant extent for ocean transport will depend on the oil supply situation in the 1980s and 90s; developments in ships' engines; and, more importantly, the philosophy then prevailing relating to the conservation of the world's non-renewable resources.

The Royal Air Force has no operational aircraft fitted with Omega but the author was closely associated with two assessments of the system planned and flown by R.A.F. navigators. Both series of flights used the Marconi Elliott AD 1800 equipment. The first flights were from Boscombe Down in mid-1973; the second series, arranged by the Department of Air Warfare at the R.A.F. College, Cranwell consisted of two flights over the North Pole in September 1976.

When we started surveying Megalithic sites in Britain we used a cloth tape, but after some years it was realized that it was necessary to be more precise and now we use a steel tape for the important sites. Similarly with astronomy; at first we considered it sufficiently accurate to work to ¼° but now we know that it is advisable to work always to within a minute of arc. This is because we have found out that the erectors of the stones sometimes used distant foresights, either artificial or natural, and by using these they could get an accuracy of better than a minute. The method of observing was for the operator to watch the edge of the celestial body grazing a foresight or running down the edge of a hill. He moved sideways until he got exact coincidence and then marked the position. This first came to our attention when we measured up the site at Ballochroy on the west side of Kintyre.

There are a number of ways of reducing the running cost of existing ships by making use of power sources which are freely available to them in their environment. This paper first of all considers briefly some possibilities other than wind power and then discusses the use of wind as an auxiliary source of propulsion in power driven ships.

Ocean Currents. Ship navigators of course already make considerable use of ocean currents when planning economical voyages. However a number of rafting voyages made for various reasons in the last few years point to the possibility of sending bulk cargoes at slow speeds across some parts of the seas carried principally by the currents. The principal problem is perhaps the pure financial one of taking the capital value of the cargo out of circulation for the time involved in such transportation.

Like so many Americans in this Bicentennial Year I find myself reflecting more and more on our heritage, the present state of affairs and our future. As Director of the Defense Mapping Agency I am especially aware that I am in a line of succession that can be traced back to Robert Erskine, the first Geographer-Surveyor to the Continental Army under command of George Washington. This has naturally impressed upon me the more than 200-year service that my organization and its predecessors have rendered to the Armed Forces of the United States, and incidentally our maritime fleet.

This paper reflects nearly three years experience of flying with Omega and suggests that in an Omega with doppler fit the necessity for the continuous compass feed can be turned to advantage by using Omega to measure and display the accuracy of the feed, which can then be applied as a system tracking correction to the doppler. The equipment we have been evaluating is a prototype Marconi Elliott AD 1800 comprising a receiver and computer in a 1 ATR black box in the avionics bay, a control display unit on the navigator's desk and an aerial input from the ADF 2 sense aerial, via a pre-amplifier and splitter that allows Omega continual use of the aerial; the ADF 2 shared access to it as required. In three years we have effectively had one hardware failure per year. These were a timing card fault, a 10 V power supply failure and a sticking ‘INSERT’ button. All these faults were detectable pre-flight; we have had no inflight equipment failures.

As a replacement for the Loran A systems installed on approximately fifty B-707/300 aircraft and to have this replacement fully operational by the end of 1977 only two options were available: the very well proven but relatively costly inertial systems and the almost totally unproven but potentially much less costly Omega. Economic considerations played a major role in this choice in view of the limited remaining useful life of the aircraft involved. The general object of the programme was to assess the acceptability of Omega as a pilot-operated substitute for Loran A in aircraft also equipped with dual doppler/computer navigation systems. Critical aspects of the use of Omega which were to be investigated were:

(i) the availability of adequate Omega signal coverage on a reasonably worldwide basis,

(ii) the normal in-lane accuracy of the Omega position output,

(iii) the in-lane stability of the Omega position output, i.e. susceptibility to ‘lane-slip’,

(iv) the reliability of the airborne Omega hardware,

(v) the operational suitability of the control/display units.

The big square-rigged ship, contrary to popular or ignorant view, was (or could certainly be) a most effective machine for the conversion of the sea winds into power in and by her sails, and could make useful long voyages carrying heavy bulk cargoes at minimum cost and minimum loss, while at the same time offering that rarity of these days—a good measure of contentment and satisfaction for her officers and crew. She was not—and I should think never was—a lumbering old ‘windbag’, more or less drifting about the seas from one port towards another, hopeful of arriving somewhere some day. When for example, we sailed in the four-masted barque Parma from an outport in Spencer Gulf, South Australia, bound non-stop towards Falmouth, Plymouth, or Queenstown for Orders (as the old charter parties read), with five thousand tons or more of grain in sacks stowed thoroughly well down below, we did not set out hopefully on a drifting-match vaguely in the direction of North Europe, some 15, 000 miles away.

The north-east coast of Australia is fronted by the world's longest coral reef system, which stretches in a north/south direction between latitudes 9° and 24° South. Although its outer limit is at distances of between 20 and 120 miles from the coast the enclosed waters are relatively shallow and contain many islands, detached reefs and shoals. The shipping lane between the coast and the Great Barrier Reef is known as the Inner Route. Torres Strait, its northern entrance, although extensive is shallow throughout and encumbered by reefs and islands to such an extent that only one route through it has been lit. The alternative routes are shallow or tortuous.

At first sight, it may seem inappropriate for an equipment manufacturer to present a resume of operation experience in the use of Omega at sea. The manufacturer is however a natural collection point for user experience and bad news travels fast while good news rarely travels at all!

The Omega transmitter network has improved considerably during the last year and with the exception of Australia all transmitters are now usable for navigation, with a typical reliability exceeding 99 per cent. This has only occurred in recent months, as previously coverage was only available in the northern hemisphere and it is users who frequently operate in this area who have become familiar with the system and gained confidence in its use.

The pattern of surface winds on an ideal non-rotating uniform Earth would be related to the distribution of surface temperatures. This would lead to atmospheric pressure gradients which, in turn, would produce surface winds. The effect of the Earth's rotation produces the so-called ‘Planetary Wind System’, and the actual pattern of surface winds is often considered to be a modification of this. But many factors influence the global wind system to such an extent that the explanation of any part of the system at any given time is a matter of considerable complexity. Moreover, experience has amply demonstrated that despite the close attention of physicists the accurate forecasting of winds for more than a day or so ahead has not met with hoped-for success.

For a long while now positions on the surface of the Earth have been fixed by observing the altitudes of two heavenly bodies. The equations:

include on their left-hand side two observed zenith distances and on their right-hand sides the required values of latitude and longitude. The history of celestial navigation records many different solutions to the problem, one of them being the observation of equal altitudes of the same body east and west of the meridian, usually the Sun, or of two different stars. If only the local time is required it is not even necessary to measure the exact altitude.

The Japanese Maritime Safety Agency has established a Tokyo Bay Traffic Advisory Service Center at Kannon Saki at the entrance to the bay in order to promote the safe navigation of vessels. The Center is equipped with radar linked to a computer. The information and control service has been operational from 25 February 1977.

Information will be broadcast to all vessels concerning the traffic schedules of very large vessels, the movement of fishing craft and of other vessels on the traffic route or in neighbouring waters. Transmissions are also made by v.h.f. individually to any vessel requesting information as to her position or the movements of other vessels.

The NAVSTAR Global Positioning System (GPS) is a satellite-based navigation system that will provide extremely accurate three-dimensional position fixes and timing information to properly equipped users anywhere on or near the Earth. The system will be available continuously regardless of weather conditions and will find extensive utilization in improved weapons delivery accuracies, range instrumentation, &c. Furthermore it will provide an ultimate saving in the number and cost of navigation and position-fixing systems currently employed or projected. It is a Joint Service programme managed by the U.S.A.F. with deputies from the Navy, Army and Marines and the Defense Mapping Agency. The system concept evolved from U.S.A.F. and Navy studies initiated in the mid-1960s. Current programme plans call for the deployment of six satellites in 1977 to permit demonstration and evaluation tests over the continental United States. The system will then be expanded through the deployment of additional satellites into an operational 24-satellite system.

If sailing vessels are to return to the oceans to carry freight, then, because of different hull and sail characteristics, the climatological routes will have to be re-assessed, probably by means of computer methods. Weather routing techniques for assisting a sailing vessel to follow the safest and most economic route across an area where barometric depressions are dominant will have to become more refined, and updated and transmitted by radio more frequently than is the case at present.

There has been, and always will be, some debate about Marconi's probable mood when in the summer of 1897 he left Italy by train for London, where his new invention was at last to find the encouragement and financial backing needed for its practical realization. His enthusiasm must have been damped by a marginal note by the Italian Minister of Posts and Telegraphs in his report on the historical experiment at Pontecchio—that young Marconi should have himself admitted into a well-known Roman clinic for mental diseases!

This paper reviews the research carried out at the University of Hamburg on the predicted performance of the Dyna Ship, a project for an advanced sailing merchantman. The proposed rig incorporates a series of unstayed hollow rotatable masts with terylene sails set along aerodynamically curved yards. The masts and sails are handled hydraulically by remote control from the wheelhouse.

Sailing ship research at the Institut für Schiffbau (IfS) of Hamburg University probably began with a paper presented by Thieme to the Schiffbautechnische Gesellschaft (S.T.G.) in 1955 on the mechanics of sail propulsion. When during 1961–6 the Hamburg Research Council promoted a broad research programme on wind forces on ships, covering all current modern ship types, the opportunity was taken to include also the problems of wind propulsion. This part of the investigation was especially stimulated by an inquiry by Wilhelm Prolss, who proposed a new height-restricted wind propulsion system for large ships in line with modern technology and aerodynamics, now known as the Dyna Ship.

The need to improve and regulate navigation in the Gulf of Suez became urgent when the Suez Canal was reopened in June 1975, and urgency increased with the number and size of ships passing through the Canal. In 1975 the Suez Canal Authority embarked on a three-phase development operation over a period of six years; the first phase, completed in 1976, allowed the passage of vessels having draughts of up to 38 ft, while the final phase, initially due for completion in 1981 but later extended to 1983, will allow the transit of vessels having draughts of up to 68 ft.

Since 1960 there has been a revival of interest in the Chinese, or junk, rig for small sailing yachts, and an increasing number of seagoing cruising boats are now appearing with it. It may therefore be appropriate to consider what, if any, application the rig could have to commercial sailing vessels in the western world.

The rig carries only one fully-battened sail on each mast, and may have any number of masts from one upwards. In its larger sizes the sail, complete with its yard, battens, and boom, is very heavy, and the whole weight has to be carried by one or more halyards from the masthead. Traditionally, and preferably, the mast is completely unstayed, being supported only at the step and the partners and standing up like a tree, or cantilever.

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.