A Defence of Astro-Navigation in the Age of GPS

Kenneth, our instructor, put down his mug of yerba mate and looked at us. “Why bother learning astro-navigation when we have perfectly good GPS?” It was Day 1 of the RYA Yachtmaster Ocean Theory course, and as we huddled in the cold training room of the Falkland Islands Defence Force HQ in Port Stanley, I realised it was a question I hadn’t really asked myself before signing up for this. Why was I here?

I suspect the answer was as diverse as the four individuals sat silently looking back at Kenneth. Here we were, different nationalities, different sailing backgrounds, different ages and yet we’d all paid up and turned up for 5 days of mental maths.

Evening homework aboard Amundsen during the theory course

Puzzling over a plotting sheet at the Victory Pub in Port Stanley

RYA Instructor Kenneth awarding Chris and Miquel their YM Ocean Theory certificates

Two weeks later, now 1300 miles east of the Falklands, we are approaching Tristan da Cuhna, a tiny dot of an island in the enormity of the South Atlantic. We’ve built trust in our sun sights to correct our dead-reckoning, but will our work be precise enough to find the island? Other than the test of achieving landfall on Tristan, I was also beginning to arrive at a nebulous answer to Kenneth’s question, for me at least.

Ian, Claire and Skipper Paul taking sun sights

The stock answer, oft given by those sailing magazines that we all read, is that GPS might fail one day, and then we’ll all be truly lost and done for. Abandon hope, all ye who set sail on the sea. I’m sure there are instances of severe solar storms, signal scrambling in war zones, or unfriendly nations that might wish to bring the whole satellite constellation crashing down around our ears. Or perhaps a lightning strike might zap the boat’s electronics. But I’m not a doomsdayer and on reflection I knew this wasn’t why I wanted to add this skill to my sailing repertoire.

For me, the competition between the accuracy of astro-navigation and 21st century GPS isn’t the point. After all, if we took every leading-technology option, why would we bother sailing at all? It’s invariably cold, wet, slow and uncomfortable. Let’s just fly, or drive there. And yet it’s not a masochistic thing, with macho-men out to prove a point, at least not for most of the sailors I’ve had the pleasure of sharing a chat on the rail with. It seems to me that we do it for the same reason that people still buy stick-shift manual cars; make a home cooked meal from scratch; or grow their own tomatoes. It’s not that the end result is better, or easier. It’s the mastery of skill of something that is difficult, yields pleasing results, is tactile and real.

Crumpling up some calculation errors

One of the interns at the office watercooler once asked me: “What makes a really good sailor?” At different times, we need to be an engineer; chef; athlete; tactician; entertainer; psychologist; project planner; conservationist; meteorologist. In the last week of creeping across the South Atlantic, I’ve learnt that astro-navigation is similarly multifaceted. There’s the informed guesswork of dead-reckoning; the physical skill in fine-tuning and caring for the sextant; the art of bringing a celestial body down and ‘calling it’ when on the horizon; and the bookwork sums of reducing the sight. Even the plotting of a fix on a scrap of paper is as much craft, as it is science. Each skill different, each imperfect, each satisfying, and together more than sufficient to inform a position for practical purposes.

Sail manoeuvres under the stars

So, if you’re the kind of person who chooses to plod across the sea under sail rather than burn diesel; or turn-off the autohelm and feel the pull of the helm yourself, then maybe you’d also enjoy adding Astro-Navigator to your skill-set resume. Maybe Kenneth should have asked: “Why bother using the GPS?”

Photos by Chris Streiff, Kate Schnippering, and Paul Guthrie.

Ian Cleaver

Yachtmaster Ocean Student