Today’s sailors rely on GPS for position finding and passage making. But what happens if your electronic navigation systems fail?
This book provides you with simple, practical, get-you-home navigation techniques that could save you in an emergency whilst sailing.
These easy techniques require no complicated mathematics. Learn the principles of navigation and you will have confidence in your decision-making when you need it most. You will also learn how to make simple instruments using materials and equipment likely to be found on every boat, and how to use them at sea.
With colourful and clear diagrams to aid learning, you will be confident in continuing your passage in a safe and seamanlike manner if the electronics let you down.
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. . . three kindes of Sayling, Horizontal, Paradoxal, and Sayling upon a Great Circle
John Davis, The Seaman’s Secrets, 1594
The techniques that once made piloting, dead reckoning and celestial navigation separate skills, are history. Nowadays navigation depends on accessing detailed and accurate data provided by an array of electronic devices that do not care if you are inshore, offshore, or in the middle of nowhere. But take these clever instruments away and the flow of data dries up, and we are lost unless we find some other way of acquiring the information that will allow us to continue on our way.
It can be done and has been done for thousands of years. Sailing without electronic instruments demands more of the navigator. He or she is no longer a button pusher but a combination of a mathematician, astronomer, biologist, meteorologist, cartographer, and geographer. It is daunting, but the biggest challenge is in acquiring or re-acquiring a mindset for another kind of sailing.
Always think positive. A lack of instrumentation and charts is not a disaster. You are not inventing the wheel. Sailors have been navigating without instruments far longer than they have with them. They have even sailed round the world without them. Take comfort in the fact that you are not the first.
Be happy living with uncertainty. GPS has accustomed us to pinpoint our positions accurately all of the time, anywhere and everywhere. At one time, knowing your position to within a handful of metres was only possible if you had correctly identified and taken bearings or transits on several charted features. Unless you were anchored, the position had a half-life measured in minutes. The further you travelled the less certain your position. You were not lost, but where you were became an educated guess rather than a certainty taken to several decimal places.
Uncertainty means your position contains unknown errors. The only certainty is that you are not where you think. Sometimes a known error is better. You still do not know your precise position but at least you are making mistakes of your choosing.
Digital navigators have been known to carefully log their vessel’s GPS coordinates and minutes later run aground. They have failed to relate this information to the real world.
Always doubtful of his position, a Crash Bag Navigator must remain spatially aware and keep a plot running in his head. In other words, he must have a mental picture of where the boat is in relation to the world about it.
You do this all the time. When travelling between home and work, at any point on the journey you can point towards your home, destination, or places in between, without any hesitation. You know where you are without looking at a map.
Similarly, the Crash Bag Navigator knows what course he’s steering and what speed he’s making. He always has in mind a fair approximation of the boat’s position and its relationship to landmarks and hazards. He uses as many independent ways as possible to check his direction, position, and speed. Each check gives a slightly different answer but they should all lead to more or less the same position.