Route Planning

Some voyages start as a dream, but end as a nightmare, usually due to lack of planning and inadequate preparation. Almost any well found modern sailing boat is able to travel from point A to point B under most conditions, provided the length of time it takes does not matter. Whether this is worth doing or not is highly debatable. Captain Bligh nearly had a mutiny on his hands when he stubbornly tried to round Cape Horn from east to west in the middle of winter. He finally gave up and turned around only to find an even greater challenge in the Tahitian vahines. Evidently, even the best forward planning could not have foreseen that kind of danger.

Fortunately the factors that have to be taken into account when planning an extended voyage are more predictable, and most of the dangers that can threaten a cruise are well known. The wise navigator planning an offshore voyage will try to take full advantage of the favourable winds and currents and avoid encountering any extreme weather. An offshore cruising boat should be well enough constructed so as to be able to withstand the average gale, and fortunately along the routes described in this volume the frequency of violent storms is extremely low during the accepted 'safe' cruising season. The main danger to be aware of are tropical revolving storms, whether these are called hurricanes, cyclones, typhoons or willy-willies, but since these affect known areas during certain times of the year, they can be avoided. This is where advance route planning has a major role to play, as it is perfectly possible to plan a voyage to all the popular cruising areas with virtually no risk of encountering a hurricane, cyclone, or typhoon.

Another element that must be taken into account when planning a voyage are the few areas of the world considered to be dangerous because of piracy, drug trafficking, or high criminality. Because of their human nature such dangers are more difficult to predict than natural phenomena, although the areas to be avoided are usually known and the sailing grapevine sounds warnings about areas that should be given a wide berth, be it some of the islands between Indonesia and the Philippines, certain countries in East or West Africa, or parts of the Red Sea. This is where a marine SSB radio or an amateur radio can be very useful since it allows one to obtain information from other sailors cruising in areas which one intends to visit in the immediate future.

Yet in spite of all the information available and the fact that so much more is known about the weather systems of the world, small boats still come to grief every year often because their skippers ignore all warnings and decide to spend the hurricane season in an area known to be hit by these violent storms. Less traumatic, but nevertheless uncomfortable, is the realisation made each year by owners of boats from the west coast of America, who find themselves in some South Pacific island at the end of a pleasant downwind cruise without the slightest idea of how to get back home. Eventually some choose the logical solution and carry on westwards, adding thousands of miles to a cruise, which has turned into an unplanned circumnavigation. A certain degree of advance planning could have made life easier. Such lack of forward planning is the main reason why there are always boats for sale in Caribbean ports, their disenchanted European owners not relishing the return voyage across the Atlantic.

On the other hand, there are obviously instances where either by force or by choice one has to fight the elements to reach a certain point.

After transiting the Panama Canal in Aventura we decided to visit Peru and the west coast of South America, before starting our cruise among the islands of the South Pacific. As we were very determined to sail to Peru, the only alternative to a long beat against contrary winds and the Humboldt current would have been an even longer detour around Cape Horn or through the Magellan Straits. Our decision to go against the weather was only taken because of our wish to visit a particular place. When planning a longer voyage, however, the most important thing is to make the best use of favourable winds and to avoid bad weather by choosing a suitable course and, above all, by being in the right place at the right time.

When starting to plan a voyage one of the first requirements in the planning stages is a gnomonic chart for the longer offshore passages one intends to undertake. Although GPS has obviated the need for such charts it is wise to have one on board, and to be familiar with their purpose and how to use them. A gnomonic chart is necessary because the ordinary navigational charts, based on the Mercator projection, cannot be used for planning an offshore passage of more than a few hundred miles. On the Mercator charts all meridians are represented as straight parallel lines that do not converge at the poles, as meridians do in reality. This means that any straight line drawn between two points on one of these charts based on the Mercator projection is not necessarily the shortest distance between those two points, and although a ship that sails such a course will reach its destination, it will not be by the shortest route. To be able to sail more efficiently it is necessary to establish the great circle route, which is the shortest distance between two points on the surface of the earth.

The principles of great circle sailing have been known for a long time and it is believed that great navigators such as Columbus and Magellan were already acquainted with the subject. The advantages of sailing along a great circle route were first mentioned in a work by the Portuguese astronomer Pedro Nunez in 1537. They were brought to the attention of British seamen in the book The Arte of Navigation translated into English by Richard Eden in 1561. Other works also referred to the applications of great circle sailing, but the term itself appears to have been coined by John Davis in a book published in 1594 under the title of Seaman's Secrets, which described 'three Kinds of

Sayling -Horizontall, Paradoxall and Sayling upon a Great Circle'.

It was about the same time that the Dutch mathematician Gerhard Mercator published a universal map on a projection that now bears his name. A course represented by a straight line on a Mercator chart is called a rhumb line and for short voyages sailing along such a line between the port of departure and that of arrival makes a minimal difference. In order to find the shorter route for a longer passage, the same straight line will have to be drawn on a gnomonic chart, which uses a different projection with meridians converging at the poles and parallels of latitude represented by curved lines. Any straight line on a gnomonic chart is part of a great circle and is indeed the shortest distance between the two points joined by that line. Because gnomonic charts cannot be used for navigation, the great circle track drawn on such a chart has to be transferred to a Mercator chart. This is done by making a note of the latitudes at which the great circle route intersects successive meridians which have been selected at convenient intervals, usually at 56. These positions are transferred to the corresponding Mercator chart and joined by straight lines. This succession of rhumb lines approximates very closely the actual great circle track for that route.

This rather cumbersome method of finding the great circle track for any chosen route can be avoided by solving the problem not graphically but mathematically. All this is taken care of now by GPS, which gives both the great circle course and distance to the next destination with the added advantage of these values being constantly updated. However, GPS only does this when one is already underway. Therefore, for planning purposes one should obtain either a gnomonic chart or a software programme for one's computer.

The purchase of gnomonic charts is therefore no longer absolutely necessary for those who intend to calculate their great circle course by other means, although acquiring the pilot charts for the oceans that will be crossed is essential. These charts are published by the US Department of Defense Hydrographic Center and can be obtained from the usual chart agents. Pilot charts are issued for all oceans of the world and give monthly or quarterly averages of wind direction and strength, currents, percentages of calms and gales, limits of ice, tropical storm tracks, and other kinds of information. The data contained in these charts is based on observations made by ships that have passed through those areas and although they give an accurate overall picture of weather conditions for a certain time of year, they are only averages and must be regarded as such.

With the help of the relevant pilot charts for the area to be sailed and the directions contained in this book, planning a voyage can start in earnest. In order to make it simpler to draw up the general outline of a longer cruise, some hypothetical voyages are described in the next chapter. These examples are only meant to show what can be done in a g;iven amount of time. Both short term and long term planning are finally the responsibility of the skipper who knows best what are the capabilities and limitations of his or her crew and boat.

The importance of long term or forward planning can be seen from the following example. Presuming that a cruise of a few months is planned in the Lesser Antilles, the order in which the islands are visited should be determined by subsequent plans. Most people leave from the Canaries concerned only with crossing the Atlantic by the fastest and most convenient route, their landfall in the Caribbean being decided by many factors, but not always by long term considerations. If one is planning to sail to Europe or the USA at the end of the cruising season in the Caribbean, the logical way to cruise through the islands is from south to north, so that the same ground will not be covered twice. On the other hand, if the voyage will continue in the Pacific and a transit of the Panama Canal is planned, it makes more sense to end the transatlantic crossing in one of the islands further north, such as Antigua or Guadeloupe, and then sail down the chain of islands towards Grenada or Venezuela. Such a route would ensure better winds when sailing among the Lesser Antilles and also a shorter passage to Panama when the time arrives. The passage across the Caribbean Sea can be very boisterous at the end of winter and a start from one of the ABC Islands off Venezuela (Aruba, Bonaire, or CuraƧao) can make that leg shorter and more pleasant. An additional advantage of this route is the fact that the southernmost part of the Caribbean is very rarely affected by hurricanes, so that if the cruise is delayed for any reason, the boat will be in a relatively safe place.

Equally important when forward planning is to allow certain subjective factors to influence the choice of routes. An order of priorities has to be decided and this is usually the point at which one must be prepared to face up to one's own limitations. All too often people are ashamed to admit to others, and even to themselves, that they are afraid of a certain passage. A good example is the rounding of the Cape of Good Hope, miore aptly called the Cape of Storms, which is indeed a very dangerous area, especially if one is^ot too confident that the boat could take a knockdown or capsize, which is an eventuality that must be faced by all those who take this route. There is absolutely nothing wrong in avoiding such a passage and this can be done easily by choosing the Red Sea route instead. However, this decision must be made well in advance, ideally before going through the Torres Strait and not on the eve of departure from Mauritius.

Reliance on auxiliary engines has become an accepted part of modern cruising and this is the reason why on certain routes skippers are advised to have a good reserve of fuel as this can make a great difference to the length of the passage. The convenience of being able to motor through the doldrums and not be becalmed for days or weeks is one such instance, as is the ability to power against a strong outflowing current to enter a lagoon, which otherwise could not be entered. Filling up one's fuel tanks before a windless passage is part of good forward planning as is choosing a port with good provisioning, refuelling and repair facilities for the start of long offshore passages.

An important element of advance planning is to be aware of official requirements in the countries to be visited and to know where one may need visas, vaccinations, or cruising permits. Much of this practical information is contained in the companion volume to this book, World Cruising Handbook. In spite of sailing boats being able to visit more countries than in the past, in many places formalities have not been simplified. The captain must be aware of specific requirements and the location of the official ports of entry; ignorance of local regulations will not be accepted as an excuse. In Australia, for example, any foreign national, except New Zealanders, arriving without a visa will be heavily fined. So as part of forward planning, one may have to plan a detour to a country where there is a diplomatic mission issuing the necessary visa. Choosing the right place, ideally close to an international airport, is equally important when picking up or dropping off crew. Just as important for long term cruisers is to plan regular overhauls in places with good repair facilities. My World Cruising Guide was written very much with that objective in mind.

These are some of the factors that can influence planning, both in the short and long term. However, what is needed at all times, and especially once a cruise has started, is a good dose of commonsense, which will help solve most problems. Nowhere is this more true than in the realm of navigation, particularly in view of the current reliance on GPS navigation. For example, if one is not too sure about the position of a certain reef, island, or any other danger, it is generally safer to assume that the latitude stated is more accurate than the longitude. The coordinates of most of these dangers were fixed by navigators before the advent of precise modern instruments, and many charts of remote areas have yet to be corrected. This is why it is still perfectly valid to use the practice of the masters of the sailing ships, who always tried to 'run down' the latitude of a given place, so as to maximise the chances of finding it. On the other hand, if one wishes to avoid a certain danger, the main thing to avoid is its latitude. As many ocean passages along the popular cruising routes are from east to west, this means that it should not be too difficult to choose a safe latitude and stay on it when approaching a known danger.

The influence that such commonsense can have on good seamanship is illustrated by examples in my previous survey books, and one conclusion I drew after talking to a great number of experienced sailors was that one of the most important qualities to have while sailing is patience. A little humility and respect for the powers of nature are undoubtedly just as important and this is probably the explanation why superstitious sailors prefer to say that they are 'bound for' their destination. Many things can happen to stop a ship from reaching its desired destination and careful planning has a major part to play in bringing a ship safely home. ;

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