According to Flamsteed's own account, the Royal Observatory was founded as a direct consequence of the representation in 1674 by a Frenchman, who described himself as Le Sieur de St. Pierre, to the English Court that he had discovered a method of determining longitude at sea ‘from easy celestial observations’, and claimed the appropriate award. The solution to the ‘longitude problem’ was then, as it had been for many years and was to be for a further 90 years, of paramount importance; several countries had offered large prizes for a practical solution, and l'Observatoire de Paris had been founded in 1667, a year after l'Academie Royale. (Observations were systematically made for the purpose of improving the determination of longitude by observation of the satellites of Jupiter; but this method, successful on land, was doomed to failure because of the impracticability of using long-focus telescopes at sea.)

Captain Emden of H.M. Coastguard's Dover Strait Operations Centre discusses the problems encountered in setting up the experimental Dover Strait Surveillance Scheme and inaugurating the Information Service. The paper, which was presented at a meeting of the Institute in London on 20 November 1974 with the President, G. E. Beck, in the Chair, describes the service today, the results so far achieved and what it hopes to do in the future. A note on the results of surveillance operation between April 1973 and December 1974 will be found at page 244 of this Journal.

The marriage of the computer with the collision avoidance (C/A) radar permits a higher order of manœuvrability finesse than is possible with the plotting board. Given the computer as a new tool, the marine systems engineer is faced with the question of whether to attempt a radical improvement in the art of collision avoidance displays, or whether merely to introduce a marginal extrapolation of the existing art. That the first course of action may be necessary is evident from various studies of the modern marine traffic environment; thus a recent study by the United States Coast Guard for the Department of Transportation showed that ‘…the total probability of collision avoidance for this condition [surrounded by a significant number of ships] requires an analytical solution quite different from one which would relate to a sparsely populated area’. Indeed the increase in shipping density, collision rates, speed and size of the newer ships, economic pressures and ecological constraints demand a radically different approach to solving the collision avoidance problem. The marine electronics industry has responded by developing collision avoidance systems of various types. Many of these are relatively straightforward extrapolations of existing art but one at least, the Sperry CAS, goes beyond a simple extrapolation and is a radical departure from conventional practice.

The submarine operates in three dimensions and whilst it has operating constraints in common with the surface ship it has others peculiar to the added dimension. This paper, which was presented at a meeting of the Institute in London on 18 December 1974 with Captain R. Maybourn in the Chair, discusses these constraints as they affect submarine safety and attempts to identify those which are caused by modern commercial activities. The views expressed are those of the author and should not be taken as a statement of Ministry of Defence policy.

This paper deals with the facilities for landlall that can be provided by lighted aids to navigation. The relationship between the navigational errors of ships approaching from the open sea and the performance to be selected for a landfall light is worked out. The probabilities of a successful landfall in various circumstances are then analysed. Finally the limitations of light as the sole aid to navigation in the process of making a landfall are discussed. Rear Admiral van Hooff was for long head of the Netherlands Pilotage and Lighthouse Service; Ir. Sirks is technical director of the Netherlands Lighthouse Service.

On the night of 2 September 1974 Morning Cloud, a 45-ft. ocean racer belonging to the Rt. Hon. Edward Heath, was sunk in a severe south-westerly gale off the south coast of England. The boat was on passage from the east coast to the Solent with an amateur crew for the passage, two members of which lost their lives. Here K. Adlard Coles, a Gold Medallist of the Institute and author of the classic work Heavy Weather Sailing, describes the circumstances in which the disaster occurred as told to him by Don Blewett, who was skippering the boat at the time. Don Blewett's own account appears in Seahorse (Jan./Feb. 1975) the magazine of the Royal Ocean Racing Club.

In the western North Pacific and the South China Sea the typhoon is one of the most fearsome elements a ship can encounter and one of the major decisions that must often be considered is whether to seek, or remain in, the shelter of a harbour or to take evasive action and ride out the storm at sea. With the many variables involved, such as topography, the different directions of approach of tropical cyclones, type of holding ground, size and shape of the ship, &c, it is often not possible to stamp a particular harbour as safe or unsafe. This paper deals with some of the many factors that a Master should consider when deciding to remain in, or sail from, Hong Kong on the approach of a typhoon.

As one of many disciplines which involve the study of bodies and their motion, the science of navigation is heavily indebted to Sir Isaac Newton (1642–1727). Newton's outstanding contribution to science was his conception of the abstract idea of force and its mathematical formulation. This enabled the development of quantitative mechanics through the application of, for example, his Law of Inertia and his Law of Universal Gravitation. Whilst limitations in Newtonian physics have now been exposed at the level of sub-atomic particles moving close to the speed of light (Einsteinian physics), Newton's Laws remain the foundation stone to the solution of most everyday dynamical problems.

The practical navigator relies on his ability to perform two fundamentally distinct operations: fixing his position and determining the course to steer. Guidance, in the sense that he receives (or generates within his craft) signals which continually define a vector coincident with his desired track, is not normally available to him.

Certain radio aids, notably the hyperbolic navigation systems, have however, frequently been used in the guidance role where the direction in which the signals can be particularly easily interpreted happens to coincide with the course to be steered. Thus, flying down a Decca lane is an acceptable operational technique which corresponds to making the aircraft follow the locus of constant range-difference to two points at known locations. It is not in principle necessary for the craft to perform the conversion from hyperbolic to Earth coordinates in order to do this.

Britain is often thought of as a maritime nation. The history books certainly support this thesis with their chronicles of explorations for trade routes, of the development of overseas commerce, which became rather absentmindedly an empire, of the growth of a navy to defend these interests. As an island race which aspired to global enterprise, maritime affairs have never been far from central policy considerations as our livelihood began to depend increasingly on overseas trade routes for food, raw materials and export markets. And along the way we developed merchant and fighting marines that were supreme in their day. From this global perspective we have been and will, probably, always be a maritime nation.

The size and construction of powerboats are governed by the international U.I.M. which has established classes related to engine size and length. Class I boats, where most of my experience lies, can have a maximum length of 4.5 feet and power is limited to petrol engines of up to 16 litres. The speeds of the fastest boats are in the region of 85 m.p.h. with full fuel on board, increasing to around 90 m.p.h. at the end of the race. Over a ton of aviation spirit is carried as fuel. This speed can only be fully utilized in fairly calm conditions. Trim tabs on the transom and a jack for the stern drive units help the driver to keep the boat on the water.

I would take issue with Spooner on his article in the April 1974 issue of the Journal. On a clear night, with no navigational hazards, a ship is reported at green 30, three miles! An assessment is made and decision to alter course to starboard is ordered. In this time the approaching vessel has made her own decision and altered course to port. Why therefore is the approaching vessel criticized for a port alteration? in my opinion she, the ‘stand on vessel’, has taken such action as to avoid collision without bringing on a close-quarters situation. On such a clear night the approaching vessel must have been visible for at least ten miles and at that range would have been showing all her lights, a clear case for an alteration to starboard on the part of Spooner's vessel to pass clear of the other vessel port to port. Was a lookout being kept at all?