Sailing Strategy

Wind and Current

Ian Proctor

• Publisher: Adlard Coles
• Year: 2013
• ISBN:
  9781472901460
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Aviation
• Index: Technology & Engineering

Sailing Strategy is considered a racing classic. Long out of print, it has champions who have been petitioning hard for its reissue. It is considered the best book ever written on the subject, and presents in detail techniques which are still completely relevant and applicable today. The author provides a very thorough analysis and explanation of how to read the wind and currents in all conditions on a racecourse, and explains how a good knowledge and understanding of their vagaries by the racer can be used advantageously to enhance boat performance on the racecourse, and carry both helm and crew further up the fleet. For any racer wanting an 'edge' (as any competitive sailor will always be aiming for) the reissue of this long out of print gem will be a godsend. A modern classic and an ideal companion to the recently reissued Start to Win, Sailing Strategy also has a new Foreword by Bob Fisher, Yachting Correspondent for The Guardian, and columnist for Yachts and Yachting. The reissue of this classic will be welcomed by novice and experienced racers alike.

Before making major decisions, or going into battle, the ancient Greeks were accustomed to pay a visit to the oracle, there to consult their deities for advice or prophecy. The answers given were usually skilled examples of obscurity and ambiguity, for it did not pay the operators of the oracle to be wrong too often. The small boat sailor who wishes to consult his particular brand of oracle before entering into negotiations with the elements afloat, luckily has rather more reliable mediums to help and guide him.

The prime concern of this book is with the study of the actual patterns of the winds and the currents which affect the progress of every sailing craft which comes under their influence, whether it be inland or on the open sea. But before a start is made on this task, it may be interesting to point out the great extent to which small boat sailors can prepare themselves to anticipate conditions afloat.

Unless a helmsman is to be racing, it is perhaps expecting rather a lot to imagine that he will wish to make much of a preliminary study of the area in which he is going to sail. Those who go out just to sail around – and very pleasant it is, too – are probably content to take things as they find them, making the best use of what is available in the way of wind and current. They will probably ascertain if there are any local dangers and will want to use their knowledge of the wind and current to the best advantage, no doubt, but probably will not wish to indulge in much preliminary accumulation of information on the area.

The keen racing helmsman, on the other hand, cannot really afford to approach the matter in this pleasantly carefree manner and, instead of taking things as he finds them, he should be able to take advantage of things that would never be found at all were it not that his preliminary study of the area has told him what to expect. Many a battle of wits and tactics in a race has been won before ever the crews went afloat. Therefore, if he is a wise skipper, he pays an unobtrusive visit to the oracle beforehand and finds out all he can about the things that are likely to affect the struggle to get his boat over the racing course ahead of his rivals.

One suspects that the most successful generals of ancient times attached more importance to consulting what maps they had, studying the terrain over which they were about to fight and learning what they could about the strength and disposition of the enemy, than they did to the findings of the oracle which, in some variations, was dependent on the interior condition of some sacrificial animal opened up for inspection. Anyway, whether this is so or not, the small boat sailor would be better advised to consult his charts, tide tables, meteorological forecasts and so on – and to keep his sacrificial turkeys intact for worthier causes.

CURRENT PREDICTIONS

Of the two elements with which the small boat sailor is most concerned, the movement of the water on which he is going to sail is the more predictable.

It should be possible to make a fairly accurate prognostication of the action of the currents over a small area without very much difficulty. The first essential to this end is a chart or a map showing the configuration of the land bordering the water concerned. The second essential, if the sailing is to be done on tidal waters, is a set of tide tables, showing the times of high and low water and, if possible, the predicted height of the tides during the period over which the sailing is to be done.

The times of the tides are given in some of the better compiled programmes and sailing instructions for races; some of them even reproduce a small portion of the chart of the area over which the race is to take place. This information can be extremely helpful and is an excellent idea, but it scarcely goes deep enough to give the helmsman as much background knowledge of the area as he should want to have. Preliminary notices of races to be sailed on tidal water should always give the times of starts, if at all possible, so that competitors can know at what state of the tide they will be racing and can make their survey of the likely conditions on the course well in advance.

Having determined whether the tide will be ebbing or flooding and, therefore, the general direction of the current, reference to a chart, or a map, and knowledge of the normal pattern of moving streams of water – such as is explained later in this book – should enable a fairly accurate picture to be formed of the flow of the currents. Likewise, areas of slack water and strong flow should then be known and likely places for twists and eddies in the stream.

Furthermore, if the rise or height of the tide is known, study of the chart will soon indicate the depth of water over shallows and when these shallows are likely to be impossible to sail over or to dry out altogether. Chapter Three should make this clear.

Those who are sailing in a straightforward current due to the stream of a river will not have to worry about a reversal of the general direction of flow – such as concerns the sea or estuary sailor. Nor need they be concerned about alterations in depth of the water as a rule. But if the stream is anything more than a mere trickle, it will still be worth studying a map – if one of a large enough scale to give sufficient detail can be obtained – to see where the current is likely to be strongest and where the eddies may most probably be found. Winter and spring races are more likely to be concerned with the strong currents of swollen rivers than summer and autumn races, which are likely to be sailed on a thirstier and more sluggish stream.

So much for prying into the future conduct of the more predictable water on which the sailing is to be done. Chapters Two, Three, Four and Five deal with this side of the matter.

WIND PREDICTIONS

The behaviour of the wind is not so certain, as it is less subject to habit and not so amenable to prophecy, but nevertheless much preliminary investigation of the possibilities of its conduct can be made months in advance, if so desired. Here again, the chart or a map will help by showing the topographical features of the area and the pattern of the windstream from various quarters can be estimated to a considerable degree of accuracy.

Few people will care to work out the possibilities in the conduct of the windstream blowing from more than one or two different directions, but it should be remembered that the prevailing wind in the British Isles is south-westerly and that, in the south particularly, winds generally blow from the western quarter for two-thirds of the year. Another point is that, in the summer around the coast, sea breezes – blowing in from the sea to the land – are a common feature of fine settled weather. Therefore, if the likely behaviour of south-westerly winds and normal sea breezes is studied – these two being the two more probable summer winds – there is about a 75 per cent chance of covering the actual conditions of wind which will be experienced during the race.

On the eastern seaboard of North America, however, winds tend to predominate from the south as they circulate round the North Atlantic highs; on the west coast, on the other hand, the trend is northerly as the highs are to the west, although different areas can suffer strong winds from varying directions apparently subject to no particular pattern.

The southern regions of Australasia are under the influence of the Roaring Forties with their persistent westerlies. The western part of the country gets a lot of southerlies, while onshore winds tend to occur in the summer months along the eastern coast, giving way to southerlies in the winter.

These, then, are consultations of the oracle that the racing helmsman may make months in advance of his races, if he cares to. At first thought, it may perhaps seem a little tedious to make such preliminary investigations, but I believe that most small boat sailors will find that, in fact, precisely the reverse is the case. Not only does it actually increase the interest of a race tremendously if this previous study has been made, but it also spreads the interest and pleasure of the race over a greater length of time.

There are other prognostications that can be made before a race, but not so far in advance. Likely weather conditions can be gathered from weather forecasts and from simple observations made on the spot the day before the race, or even an hour or less before the start. If changes in the wind are likely to take place during the race, they can frequently be anticipated and a watch kept for the first signs of them occurring, so that if and when they do happen, the helmsman who has prepared himself in this way can perhaps put himself in a position to take advantage of them before his rivals.

LOCAL KNOWLEDGE

Another thing that can be done to gather in previous information, likely to be useful during a race, is to try to assimilate some local knowledge founded on actual experience. This local knowledge may be well named, because one of the best places to get it is frequently in the local bar while engaged in other assimilations. But there is a need to be wary of information given; you cannot always tell a fisherman by the colour of his jersey and people who do not know are often only too willing to hazard a few guesses in the hope of a free drink. It is seldom wise to lead your informant on by inviting him to confirm your own theoretical summary of the action of local currents; if he does not know what really happens, he will probably be highly delighted to act the ‘yes man’ to your suggestions and, though this may be gratifying to your ego for the time being, it is not what you are after. Anyway, the contention that you are off to seek ‘local’ knowledge is sometimes a useful and satisfying excuse to offer.

By far the best and most detailed local knowledge I was ever given was volunteered by somebody who had been commissioned by the Sanitary Department of the local town council to discover why what came out of the drains into the sea showed a tendency to wash up on the most popular bathing beach farther along the shore.

PRELIMINARY SURVEY

Finally, a survey of the area of combat in a state of pre-race calm will be invaluable. Generally speaking I would say that it is best to carry out this survey from high ground, or a high building, overlooking the racing course, though to sail over the course may be useful too, especially if it is not possible to get high enough up to get a good view of the water from the shore. If possible, it is best to do this survey when the tide is at the same state as it will be in when the race is started; this will probably mean looking at it either about 25 or 12½ hours before the start of the race, but of course this is frequently impractical.

From a height it will probably be possible to see all the marks around which the race will take place. Perhaps some useful transits (see Chapter Five) can be noted. In all probability fairly constant patches of smooth water and streaks of ruffled water will be visible from such a position, though perhaps they would not be noticed from lower down or from a small boat afloat. These patches of smooth and ruffled water may indicate the positions of wind streaks, or of currents and areas of slack water – very probably a combination of both – and the evidence should be weighed in making a decision as to what precisely is the inference of what is seen. In stronger winds there will be areas in which the water is noticeably rougher and there may frequently be lines of scum and flotsam; all these are signs giving important information on the wind and current.

CORRELATING INFORMATION

A comparison of these indications with the theoretical prognostications made previously, will either tend to confirm the latter or to throw doubt upon them. Add to this evidence whatever local knowledge may have been acquired and it should be possible to form a fairly definite opinion as to what parts of the prophecy may be trusted and what parts are less sure. These findings should be treated accordingly when planning tactics during the race. Sometimes, of course, it may pay to take a chance on some of the more doubtful advantages which seem to be offered, but they should naturally be treated with reserve.

Until experience is gained, mistakes will inevitably be made and, indeed, these preliminary investigations may sometimes lead a helmsman astray in a wild goose chase after some supposed advantage promised by the current or the wind which in fact does not materialise. But later, fewer mistakes will be made and careful forethought will begin to win races – unless there are others equally skilful, who are ‘forethinking’ even more successfully. In any case, most people find that it greatly adds to the fun of racing.

Great experience and skill may possibly eventually take the place of such detailed preparations for big races, but there are many very skilled and experienced helmsmen who consult all the oracles and leave nothing to chance if they can help it, for chance is a capricious ally and as likely to be a foe as a friend.

Experience of a local stretch of water will always put a skilled helmsman at a slight advantage over other competitors who are strangers to it, even though they may be experts on the theory of currents and tides. But expert strangers will not be at a loss to know approximately what they should do to get the greatest advantages from the currents and they may well make a better job of using the currents than less clear-thinking helmsmen with local knowledge.

What it boils down to is that there is no substitute for good local knowledge, but expert interpretation of the conditions can come pretty close to it.

A current may be a helmsman’s ally or his enemy. Whichever it is of these two is dependent on whether the boat is trying to sail more with it or more against it. When one is racing, the great thing is to make the current a greater ally and a lesser enemy to yourself than to the other competitors.

The only way in which you can do this is to have a better knowledge than your rivals of the way in which currents behave and the effects which they may have on your boat.

Though the wind may be a fickle jade and may sometimes entitle a helmsman to a hard-luck story after the race, tidal streams are fairly constant for any given state of tide, if sailing in tidal waters, or for any given strength of current if sailing on rivers.

Within limitations, it is possible for anyone with an intimate and absolute knowledge of an area of water affected by tidal streams to predict the speed and direction of the stream at a given state of tide or at a given strength of main current. Not many people have such an intimate knowledge of even their own local water, but the point is that currents are predictable, while wind speeds and directions are only predictabl...

Table of contents

• Cover
• Title page
• Table of Contents
• Foreword to the revised edition by Bob Fisher
• Preface to the original edition
• 1 Consulting the Oracle
• 2 The Way of Currents
• 3 Tides and Tidal Streams
• 4 Current and the Apparent Wind
• 5 Current Tactics
• 6 General Observations on Waves
• 7 Using Waves to Advantage
• 8 Wave Characteristics and Currents
• 9 Weather Reports, Barometers and Winds
• 10 Clouds and Sky Colours
• 11 A Typical Weather Cycle
• 12 Effect of Obstructions on the Wind
• 13 Local Thermal Winds
• 14 Gusts and Calm Patches
• 15 Winds Along the Shore
• 16 Natural Signs
• 17 Keeping a Record
• 1 Examples of a Pre-race Prediction
• 2 Table of Wave Velocities, Periods and Lengths
• 3 Table of Wind Velocity and Pressure
• 4 Some Wave Formulae
• eCopyright