In this paper, which was presented in a fuller version at an Ordinary Meeting of the Institute held in London on 20 December 1963, Mr. Kurz of the United States Maritime Administration and Mr. Bentkowsky and Captain Quinn, both of the Sperry-Piedmont Company, describe a control console for ships which was developed by the Sperry-Piedmont Company under contract from the Maritime Administration. The console, which has its sea trials early this year, comprises five sub-consoles which cater for navigation aids, communications-radar, steering, position plot, and ship condition. The paper enumerates the advantages that might be expected from such an arrangement.

This paper represents a follow-up of work previously reported at an Ordinary Meeting of the Institute and published in the Journal in May 1986 under the title ‘Navigational Aspects of JTIDS’.

Technical studies on JTIDS for the airborne applications are being directed by the Royal Aircraft Establishment (RAE), Farnborough and by the Admiralty Research Establishment (ARE), Portsdown, for maritime use, for which Systems Designers Scientific is providing technical support in a number of areas. One such field is Relative Navigation (relnav). As part of this MOD-funded work a relnav simulator has been developed at the RAE. This simulator is currently in use for the assessment of the relnav capability and has been used to produce the results presented in following sections.

This report gives a brief description of JTIDS relnav and presents some basic features of relnav performance in simple communities. Then a description of relnav performance in fragmented and loosely coupled communities is presented. Finally a brief summary of the main points and conclusions is given.

Ever since the introduction of the Air Almanac and the Astronomical Navigation Tables, requests have been received for information as to the errors that can arise in their use. Estimates of error, for particular combinations, were made on several occasions and, in 1947, the calculation was systematized; but the methods and results were not published. It is now probable that the Sight Reduction Tables for Air Navigation, A.P. 3270 (H.O. 249 in U.S.A.), and possibly the Air Almanac, will increasingly be used for surface navigation and it therefore seems desirable to put on record a precise statement of the errors that can arise through their use. The earlier work has accordingly been modified for the changes in the publications.

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.

This paper, which was presented at an Ordinary Meeting of the Institute in London on 21 November 1979, with S. Ratcliffe in the Chair, traces the evolution of airborne doppler navigation systems over the past two decades and discusses the treatment of errors introduced when flying over water. Both authors are with Decca Radar Ltd.

The object of this paper is to describe briefly the major developments which have taken place in doppler navigation systems during the past 15 years or so, to indicate the current state of the art and to examine in some detail the behaviour of doppler systems when flying over water. The year 1960 is taken as a starting point since by that time commercial doppler systems were established. A typical general purpose system of that generation (Fig. 1) consisted of the following units:

1. An antenna, probably mechanically stabilized.

2. A transmitter/receiver using either pulse or FMCW modulation.

3. A tracking system.

4. An analog computer.

5. A display of ground-speed and drift-angle.

6. A display of present position.

As sea traffic grows, so too does the problem of the acoustic pollution of fishing grounds. This paper describes the measurement and analysis of ship-produced underwater sounds and their effect on the behaviour of certain fishes. It would seem that their influence on marine organisms is a growing problem and should not be ignored by navigators, for the sounds produced by large or high-speed vessels, or even fishing boats, can frighten fish shoals or cause them to change their migration routes.

After a series of tests to measure and analyse the underwater sound, the output of submerged loud-speakers, either at sea or in an aquarium, was adjusted to ensure that the sound intensity near the fish was at the required level and the fish behaviour was carefully observed. For these experiments a hydrophone was connected to a pre-amplifier. A signal amplified by the pre-amplifier is attenuated before being sent to the main amplifier, the sound level being read directly on an indicator using the sound analysing character ‘C’. A tape recorder registers the sound signal in a flat response from 20 to 50 Hz to within 3 dB. A tracing recorder was also sometimes used and the two methods gave almost the same results.

Oceanography is concerned with the applications of all sciences to the study of the sea, and navigation, in its widest sense, with the application of any science and systematic knowledge to the purpose of maintaining safe and efficient communications across the oceans. They have something in common, but oceanographical work, whatever its future promise, is primarily academic, and navigation the application of well-tried conclusions. It would be wrong to suggest that basic studies of sea conditions are followed by systematic attempts to use them to improve navigation. Progress is sporadic, depending on individual enthusiasms and commercial enterprise as well as the efforts of government departments and professional associations. There is no sharp division between the basic work and its applications, or, after allowing for some extremes, between the scientist and the authority on navigation.

Ships' bridge watchkeeping, although the prime task of the officer of the watch, makes very low task demands in terms of information processing and required speed of response compared to most other vigilance tasks. Consequently, performance of the visual lookout task is difficult to describe and evaluate systematically. Results from an on-board observational study show that lookout lapse periods can be economically described by simple mathematical models, which assist in comparison and evaluation of task performance.

The author, a Master Mariner and Section Chief of the All-Union Research Institute of Marine Fisheries and Oceanography, Moscow, U.S.S.R., deals with the principle of clockwise rotation of the line of relative motion, as applied to simultaneous encounters with several ships. He presents arguments for a strict compliance with the well known dictum of Captain Oudet: ‘Encounters at sea are governed in such a way that each party knows what he should do and what the other should do.’ The paper was written in collaboration with the late Captain G. Shoomayko.

This paper is based on one presented by the author at the Maritime Technology 21st Century Conference held at the University of Melbourne in November 1992.

The high concentration of aircraft near aerodromes, with consequent collision risk is well known. It is at present necessary, in poor visibility, to guarantee the indispensable commodity of safety by the sacrifice of schedule regularity and fuel economy. So long as this is the case, the problem of terminal navigation and control must be regarded as one still demanding a satisfactory solution.

Many vessels trading on North Atlantic routes are equipped with weather facsimile receiving devices of various types. Ship-masters engaged on regular voyages in this area are thus able to conduct their own passage planning using the information readily available from these intruments. The capital cost in relation to other ship operation costs is negligible; in US dollars (1983) it is likely to be of the order:

There would be no problem in planning a vessel's route across an ocean if it were possible to forecast with total accuracy the actual sea state existing for the duration of a voyage. Such an ideal circumstance does not yet exist and a method must thus be used which incorporates flexibility to modify a voyage plan as actual weather varies from the prognosis. This means that a subjective approach to storm avoidance may, on occasions, be preferable to the stringent demands of a least-time track. The obsession of routing agencies with the latter method may be one reason why weather routing has not achieved the success it perhaps deserves.

A ship may be damaged or delayed by the action of sea waves on her hull or structure. Hull form and ship dimensions are usually selected on the basis of calm-water performance, rather than for sustained sea-speed.

As between the scholar and the technician, the armchair theorist and the practical man, the antagonism is as old as civilization itself. In Queen Elizabeth's days the gentleman born was the only gentleman, however ignorant, while learning was the preserve of the universities; the practical man was a mere ‘mechanician’. But there was some liberal thinking, common-sense thinking, even in those days, and one Gabriel Harvey, a well-known literary man and controversialist, spoke up boldly for the technicians. Even though they had heard no university lectures, he said, and were deficient in book-learning, it would be a bold man who would despise such expert practitioners as Humfrey Cole, the mathematical instrument maker, William Bourne, the naval gunner, Matthew Baker, the shipwright, John Shute, the architect, John Hester, the chemist, and Robert Norman, the hydrographer and compass maker. No fewer than four out of the six notable men he named were doing work that was relevant to the advancement of the navy and navigation. They were at the height of their powers in the decade preceding the defeat of the Spanish Armada, a coincidence which cannot be without significance.

The history of mechanical transport has been one of increasing speeds and there seems to be little doubt that air transport will follow this pattern. To the passenger, increased speeds mean a saving of time, and time is money. To the operator, increased speeds mean more flights per week and therefore greater earning capacity for his aircraft. This year indeed has been marked by the appearance of the four-jet air liner, the forerunner of the four hundred knot air transport.

However misleading statistics may be, they often make an interesting study and those of marine collisions are no exception. In Volume 13 of this Journal, page 430, some figures were given for collisions in fog with radar, which permitted the conclusion that, in North-west European waters in 1959, each day of fog produced 1·2 collisions. Up to and including 1959 this figure was not rising significantly.

The AN/SSN-6 Navigation Sensor System Interface (NAVSSI) Project is a new system being designed with two primary objectives; to serve as the central distribution computer for navigation data to shipboard combat/weapon systems and to serve as the electronic chart display and information system (ECDIS). The NAVSSI will operate the digital nautical chart (DNC) database being developed by the Defense Mapping Agency (DMA). Our goal is for the digital nautical chart to replace the paper chart as a legal means of ownship navigation plotting. This paper will introduce the project and will primarily explore the use of digital nautical charts for ownship navigation with NAVSSI.

We are told by Captain Greenvile Collins that Charles II was ‘A great lover of the noble art of navigation’. I think his brother, James, Duke of York, who became the Lord High Admiral at the happy Restoration in 1660, shared the same enthusiasm. Members of the Royal Society, including distinguished seamen, studied mathematics, mechanics and optics. The time was ripe for improvements to be tried out, under royal patronage, in ship design and construction as well as in the navigation of ships. English methods began to be regarded as not only the best but even as unnecessarily exacting, and we are told that Davis's backstaff was known as the English Quadrant by the French, and the English log and log-line for estimating a ship's speed through the water was better than the simpler methods popular with Spanish, Portuguese and Dutch mariners.

The invention of the balloon was almost a casual affair, unrelated to other contemporary inventions and unheralded by prior developments. The hot-air balloon could have been invented at any time since the mastery of thin textile manufacture, which can be dated well before the Christian era. The hydrogen balloon could not have come about until after Cavendish had isolated the gas in 1766. As it finally turned out, both types of balloon were invented in the year 1783.

Time and space scales are compared for selected speeds of ships in the North Atlantic and North Pacific oceans. Viability of westbound passages on some northern great circle routes is discussed.

There would be no problem in precisely weather routing a vessel across an ocean if it were possible to forecast with total accuracy the actual sea state existing for the duration of a voyage. All mariners are well aware that such an ideal circumstance is not as yet possible. Depending upon the general synoptic situation existing for the period, it is fair to make the assumption that the actual accuracy of a weather forecast deteriorates as time progresses.