From my father I learned something about surveying and the use of trigonometry – the mathematical technique for deducing the size of the unknown angles and sides of a triangle from measurements of those that are known. On our walks in the New Forest we sometimes came across the concrete triangulation pillars on which the British Ordnance Survey maps were based. Each pillar formed the corner of a triangle from which the other two corners were visible. Starting from a very accurately measured baseline, a network of such triangles extended across the whole country. By measuring the angles between the pillars using a theodolite, surveyors could determine the relative positions of each pillar with great accuracy, thereby providing the map-makers with an array of fixed points on which to build. In those days this system was still the key to land-based cartography.
Every marine chart was liberally sprinkled with ‘soundings’ – numbers representing the depth of water in old-fashioned fathoms (1 fathom to 6 feet), which crowded in even greater profusion round hazardous patches of sea. Particularly sinister were the places in the mid-ocean depths where a tight cluster indicated an isolated shoal – perhaps the tip of a ‘sea mount’ that did not quite break the surface. The Chaucer Bank, some 250 miles north of the Azores in the middle of the North Atlantic, is an example. On Admiralty chart no. 4009 (North Atlantic Ocean – Northern Portion, published in 1970) it rose up to a ‘reported’ minimum depth of 13 fathoms from waters that slide down rapidly to 1,000 fathoms or more. In heavy weather, seas would break on such a shoal – an alarming sight so far from land, and a potential hazard too. Before the advent of the electronic echo sounder in the 1920s all these soundings would have been taken with lead-lines – nothing more than a lump of lead on the end of a long, calibrated rope or wire. Triangulation could have been used the fix the positions of soundings along the coast, but what about those offshore, far out of sight of land? Of the vital part the sextant had played in hydrography – the mapping of the seas – I had as yet no idea.
As a teenager I sailed to Normandy and Brittany and around the west coasts of Ireland and Scotland. These excursions offered plenty of navigational challenges – the English Channel with its strong tidal currents and heavy shipping traffic is a dangerous stretch of water and the many rocky shoals of Brittany, Ireland and Scotland demand respect – but they did not call for the use of a sextant. Instead we relied on dead reckoning (DR – using the distance travelled and the course followed to estimate your position) corrected by radio direction-finding (RDF – fixing the boat’s position by taking compass bearings of radio beacons). If sailing at night, compass bearings of lighthouses were helpful too. While these methods worked well enough for short coastal passages, I wanted to know more: I was determined that one day I would learn how to navigate the open ocean by the sun and stars. I had not yet even seen a sextant, but the mysteries of celestial navigation already had me under their spell.
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Just ten years after seeing Mutiny on the Bounty I got my first chance to handle a sextant when a family friend invited me to help him sail across the North Atlantic in his 35-foot sloop, Saecwen.fn2 Colin McMullen was a retired Royal Navy captain and like many naval officers he was easy-going, relaxed and charming – useful if not essential qualities when sharing cramped accommodation for any length of time. Colin loved nothing better than an impromptu party. On the slightest pretext he would get out his accordion and start a ‘sing-song’, and if he was in particularly high spirits he might even put on a false beard and impersonate an ancient mariner with a strong west-country accent.
Colin was also fond of practical jokes, one of which almost cost him his life. As a young midshipman on board a small yacht being towed by a much larger vessel, he decided it would be amusing to climb along the tow rope and appear – as if by magic – on the deck of the mother ship. This meant scrambling along a heavy hawser, the middle of which frequently dipped beneath the surface of the sea. Colin was barely able to hold his breath long enough and nearly lost his grip as the cold, fast-moving water tugged at his submerged body. He was carpeted for this crazy escapade, but in the Royal Navy of the 1920s there was room for colourful characters, and it did his career no harm.
Colin had been messing about in boats since his childhood days at Waterville in County Kerry during the First World War. When he was posted to Malta in the 1930s he was given the enviable task of delivering the Commander-in-Chief’s official yacht to Venice, and I remember him talking rapturously about the summer days he spent along the Croatian coast aboard this large and elegant vessel. Most of his sailing, however, had been on a much more modest scale – notably in a small yacht called Fidget that he shared for a time with a group of fellow naval officers.
Colin bought Saecwen after retiring from the navy, and I first crewed for him when the two of us sailed her along the south coast of England from Dartmouth to her home port, Lymington, in early January 1972. It was an overnight trip and the weather was clear, cold and windless. As we motored slowly across the wide expanse of Lyme Bay I watched the ‘loom’ of French lighthouses, one of which – on the notorious Roches Douvres reef off the coast of Brittany – was nearly 80 miles away, far beyond the range at which it would normally be visible. The distant pencil beam of light rose briefly from below the horizon, sweeping up and over like the headlamps of a car making a sharp turn on the far side of a hill.fn3
In the middle of my watch I heard the hatch slide back, and there was Colin – who should have been asleep – with two cups of hot cocoa. While I steered we sat together looking up at the night sky, our breath smoking in the cold. It was then that we first talked about celestial navigation. Colin pointed out the stars to me and recalled his days as a young naval cadet, just after the First World War, when learning to handle a sextant and plot a line of position had been nothing but a chore. Now he was planning a transatlantic cruise in Saecwen and was looking forward to brushing up his old skills. Nothing was said at the time, but later that year Colin asked if I might be free for six weeks or so the following summer; the trip to America was going ahead and he was looking for crew on the return voyage to England. As a university student with time to spare I eagerly accepted the invitation: here was a chance not only to cross an ocean under sail but also to learn the art of celestial navigation from a professional whom I admired. But transatlantic passages in small boats were not yet the fairly routine events they have since become. Looking back I am amazed that my mother, who had been widowed not long before, raised no objections. She must have felt the risks were worth taking.
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On a sticky evening in early July 1973 I arrived at Falmouth, a small town on the coast just north of Portland, Maine. It was my first visit to the USA, and I had travelled up from New York on the Greyhound bus. The licence plates on the cars announced that I was in ‘Vacationland’, the temperature was in the 90s and the humidity was only slightly less than in Manhattan, though the still air was refreshingly clean. From the bus terminal I took a cab to the Portland Yacht Club, and as I walked down the jetty I caught sight of Saecwen lying at a mooring only 50 yards away. Rocky islands covered with hemlock and spruce lay further offshore. Colin was watching out for me and pulled across at once in the rowing dinghy to pick me up. It was strange to step aboard Saecwen again in such different surroundings, but as the deck gently rocked beneath my feet I felt almost as if I had come home. I slung my bag into the starboard quarter berth where I was to sleep for the coming weeks, absorbed the familiar smells, and came up on deck where Colin handed me a can of beer – very welcome in that heat. He was not alone on board Saecwen. There were two other crew members at this stage – Colin’s sister, Louise de Mowbray, and his cousin, Alexa Du Vivier, who was just seventeen. We talked