{"id":597,"date":"2026-01-21T14:45:30","date_gmt":"2026-01-21T14:45:30","guid":{"rendered":"https:\/\/yachtersworld.com\/?p=597"},"modified":"2026-01-21T14:45:30","modified_gmt":"2026-01-21T14:45:30","slug":"using-celestial-navigation-to-sail-the-atlantic-we-are-at-the-whims-of-the-seas-invisible-forces","status":"publish","type":"post","link":"https:\/\/yachtersworld.com\/?p=597","title":{"rendered":"Using Celestial Navigation to Sail the Atlantic: \u2018We are at the whims of the sea\u2019s invisible forces\u2019"},"content":{"rendered":"

Exploring the South Atlantic using celestial navigation turns into a three-year quest for a little-visited archipelago, by Kate Schnippering<\/strong><\/p>\n

\"Kate
Kate and Carlos take sun sights aboard Vinson of Antarctica. Photo: Kenneth Perdig\u00f3n<\/figcaption><\/figure>\n

One foot east, one foot west. I stand on a line inscribed in stone: the Prime Meridian, longitude of zero. This threshold marks a rite of passage for becoming a celestial navigator. It\u2019s April 2023 and I\u2019ve journeyed a long way to the UK for my RYA Yachtmaster<\/a> Ocean exam, where I\u2019ll be extensively questioned on the South Atlantic passage I sailed the previous year with Vinson of Antarctica, and on the ins and outs of my navigational records.<\/p>\n

I\u2019d spent six weeks aboard the expedition vessel, first learning the basics of wayfinding by sextant from shore, and then putting it into practice on a 4,000-mile downwind delivery strewn with storms and turbulent seas. I didn\u2019t realise then, but I was embarking on an even bigger journey that would take three years to complete.<\/p>\n

One year in, I\u2019m warming up by visiting Greenwich Observatory to see first-hand the chronometers of John Harrison, who solved the challenge of determining longitude at sea in the 1700s. As I admire the exquisite pocket watch, I imagine H4 ticking away on a creaking old ship, faithfully telling Greenwich time and keeping the rocks at bay.<\/p>\n

\"Crew\n

Crew mate Carlos taking sun sights in the South Atlantic. Photo: Kate Schnippering<\/p>\n<\/div>\n

Nonetheless, the Royal Society was unimpressed by this mechanical solution, and they withheld Harrison\u2019s prize for more than 20 years, believing a more elegant answer lay in calculating the moon\u2019s paths. Today, we navigators consider the moon the least reliable object to take sights of!<\/p>\n

Beyond the allure of duelling mathematical proofs, I\u2019m fascinated by the earlier timepieces built to time\u2019s variable rhythms. Sundial rings. Tide-watches. A Nocturnal star-clock with an extended pointer to touch time on your skin at night. I want to feel a connection with Greenwich in my bones, so perhaps someday I won\u2019t need a timekeeper to know my longitude.<\/p>\n

Celestial navigation beckons modern sailors back to a lost romance with ocean voyaging that\u2019s been stifled by a proliferation of technology. We slow down to take in more of our surroundings, and exchange full control for an unfamiliar form of guidance.<\/p>\n

\"View\n

\u2018Drop shades. Scan the sky to catch the sun in the eyepiece\u2019. Photo: Kate Schnippering<\/p>\n<\/div>\n

We form personal relationships with the sun, moon, planets, stars, islands, birds, and winds, who become the protagonists and antagonists of our stories. The art of navigation has the power to change why we voyage in the first place.<\/p>\n

I reflected back on the past year. How had I arrived at this threshold? I joined the passage on Vinson not because I needed to navigate if the GPS on my Catalina 36 Petrichor failed, but because I felt lost in a larger way.<\/p>\n

I was experiencing stagnation in my decade-long dream career at a prestigious design firm. In pursuit of impact, I found myself growing out of touch with my own creativity. I sought renewal, and turned to the unruly Southern Ocean to chase mystery, without an end destination in mind.<\/p>\n

\"The\n

The Nocturnal was an early navigation tool to determine time from the position of stars<\/p>\n<\/div>\n

Longitude, Meet Latitude<\/h2>\n

April 2022. The last piece of land receding in the distance is Isla Hornos, marking a notorious Cape where Pacific clasps Atlantic. While there is no line drawn here, I feel the two oceans clashing with omnidirectional waves of all character. They tango, tussle and trebuchet into each other. The autopilot surrenders and our skipper, Kenneth Perdig\u00f3n, takes the helm.<\/p>\n

We have too much sail up for 35 knots of wind, rushing to our five-minute appointment with a daring helicopter documenting Vinson\u2019s first pass of the Horn. Finally we reef \u2013 and tape over the GPS display of our position. From here on, we\u2019ll navigate without it. As night falls, a formidable ocean reaches before us. Our destination Cape Town lies a quarter-turn around the planet.<\/p>\n

\"Skipper\n

Skipper Kenneth Perdig\u00f3n studies the chart. Photo: Kenneth Perdig\u00f3n<\/p>\n<\/div>\n

I\u2019m one of six apprentice celestial navigators, who\u2019ve just learned in theory how to get from here to there via pencil, paper charts, almanac, tables, sextant, wristwatch, and compass. We\u2019re daunted at the task, and begin to plot our dead reckoning course hourly, estimating our compass heading and distance logged.<\/p>\n

Leaping on deck to meet the sun with sextant in hand is Carlos, exclaiming his boundless enthusiasm for planetary physics. My cabinmate, Tim, and I follow more timidly, working together to take sights and record data. Clip on to a strong-point, it\u2019s time to arm-wrestle infinity with a small metal instrument. Align mirrors with a wobbly horizon. Drop shades. Scan the sky to catch the sun in the eyepiece.<\/p>\n

Where is it? Shades are too dark\u2026 too bright!\u2026 just right. Copy the sun, drop the green orb to graze the edge of the sea-sky ruler. Mark! Record time, altitude.<\/p>\n

\"Christian\n

Christian working on navigation on Vinson of Antarctica. Photo: Kate Schnippering<\/p>\n<\/div>\n

After a math marathon through a labyrinth, Tim and I yield our first fix of latitude and longitude \u2013 correcting our course by 30 nautical miles. As the days go by, it gets easier. We face every trapdoor error in turn, slowly building trust in the process, and attuning to the experience of living on a sphere.<\/p>\n

The method we\u2019re using evolved in the 1800s \u2013 decades after Harrison\u2019s chronometers \u2013 and has a simple concept behind it: each celestial object projects a circle onto the earth, and when we intersect two circle-projections (usually morning and afternoon sun), we know we must be at one of the two points where they overlap.<\/p>\n

We can pinpoint our position anywhere on earth by comparing the expected measurements from where we think we are, to the ones we\u2019re actually recording.<\/p>\n

On a Great Circle route, the curvature of the earth matters, and our heading gradually bends. The sun takes centre-stage. Port side, declination north, marching into austral autumn. Sunrises arrive earlier as we cross timezones.<\/p>\n

\"Miquel\n

Miquel admires the moon after taking a sight at dusk. Photo: Kate Schnippering<\/p>\n<\/div>\n

We attend each day\u2019s local noon, where a sight produces our exact latitude. What keeps us racing to plot the next position is our aim to locate a petite 14-mile-wide island in the middle of the Atlantic<\/a>: Tristan da Cunha. The most remote inhabited place on earth, a settlement situated on the edge of a volcano.<\/p>\n

Two low pressure systems pass, bringing 50-knot winds and 7m swells. Closely monitoring the radar for approaching squalls, on the \u2018Betelgeuse\u2019 watch we dress in full foulies and stand by on deck. Here at 0200, perched by the aft mast above the pilothouse in horizontal rain, is a perfect moment to slow down and think through a coordinated manoeuvre together with first mate Justino, fellow navigator Chris, and 15-year-old trainee Ant\u00f3n.<\/p>\n

Celestial Navigation: Invisible Forces<\/h2>\n

While navigation can show us where we are, it cannot take us everywhere we want to go. We are at the whims of the sea\u2019s invisible forces. A third low pressure system brings tremendous head seas. Tack as we might, no amount of patience will open up a path to Tristan da Cunha. Our skipper makes the call that we must re-route, and we are crestfallen. What are we navigating for, then?<\/p>\n

New calculations show a reasonable course via Gough Island \u2013 is it worth the effort? Over the ship\u2019s satellite email, Vinson\u2019s managers Skip Novak and Jordi Griso send us the latest edition of Gough\u2019s newsletter, The Bunting \u2013 highlighting fur seal pup weighing and the small crew stationed there for the winter. Spirits pick up briefly, until the fog sets in.<\/p>\n

\"Heading\n

Heading ashore by dinghy at Tristan da Cunha. Photo: Kate Schnippering<\/p>\n<\/div>\n

Accompanying the fog are perfect sailing conditions, and we\u2019re sailing so fast we\u2019ll likely pass Gough in the cover of night. We depower sails to slow Vinson down. Kenneth informs us that if we miss our 8-mile island on a 20-mile radar range, we\u2019ll not be turning back. We plot our course every 15 meticulous minutes, aiming for Gough\u2019s centre.<\/p>\n

Instead of clear-cut sun-sights, we\u2019re plodding our way forward by dead reckoning alone. The more we can account for the invisible actors influencing our course, the higher the hopes for our needle-in-haystack island search.<\/p>\n

Rotating between sleep-deprived navigators we must collectively agree upon magnetic variation, compass deviation, leeway, and ocean currents. I roll off my night watch to cocoon into sleep, mired in doubts that our efforts will amount to anything. Good luck Rob, Tim and Maurice.<\/p>\n

\"Tristan\n

Tristan da Cunha is long way from almost everyone else. Photo: Kate Schnippering<\/p>\n<\/div>\n

When I return to the pilothouse the next morning, Gough Island has just appeared on radar. We are off-course by a mere 12 miles, almost three days since our last sun sight and 17 days since we switched off the GPS. High-fives all around!<\/p>\n

A grey silhouette is visible off starboard bow. As we draw nearer, we revel in the magic of islands forming their own microclimates. All gather awestruck on deck to watch the cloud curtain lift to reveal verdant waterfalls pouring over cliffs, scores of seabirds of flocking together \u2013 spectacled petrels, prions, sooty albatross, wanderers, and great shearwaters galore.<\/p>\n

Kenneth radios the research station, and the winter crew invite us to imaginary coffee \u2013 we all know we can\u2019t land on Gough. They line up outside, waving, as we sail by.<\/p>\n

\"Recorded\n

Recorded data for the sextant sights. Photo: Kate Schnippering<\/p>\n<\/div>\n

For whatever reason, those benthic guardians who protect Tristan da Cunha had called up the sea to bar sailors who were not yet ready, and sent us to Gough instead, a place more dazzling than I dared imagine.<\/p>\n

I\u2019m ready to embrace wandering as a form of navigation.<\/p>\n

Article continues below\u2026<\/em><\/p>\n

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Saint Lucia: not just a transatlantic stopover<\/a><\/h2>\n<\/header>\n
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At the end of a long transatlantic crossing, the island of Saint Lucia is a dreamlike landfall. Its hills and\u2026<\/p>\n<\/div>\n