BACK TO BASICS
Celestial navigation skills to reach the remote Tristan da Cunha
According to our fix, we were within 40 miles of Tristan da Cunha. Even though the island’s highest point, Queen Mary’s Peak, is 2,016m above sea level, we still could not see it, our vision partly hampered by the thick band of low cloud. As darkness fell, everyone assembled on deck trying to get a glimpse of land, but when the light finally faded we realised we would have to trust our calculations.
There were 11 of us onboard Skip Novak’s 74ft expedition yacht, Pelagic Australis. After completing a five-day RYA Astro Navigation course followed by a 10-day shakedown sail around the Falkland Islands to put into practice what we had learned, we were ready to take responsibility for the ship. This was when the real challenge started. On our way from the Falklands to Cape Town, we had been tasked with finding the small volcanic island of Tristan da Cunha, a speck in the middle of the South Atlantic, navigating only by the sun, moon, stars and planets.
At Stanley we said goodbye to our astro-navigation instructor, Alan Denham, who was flying back home to the UK. We also took the opportunity to stock up on some more fresh food. We were soon away again. As we began leaving the harbour, our skipper Edd muttered that there would be ‘no cheating’, and covered up the GPS coordinates on the chartplotter display. Had we really learned enough about astro navigation to be able to find Tristan da Cunha? We were about to find out.
We started in earnest, writing down our speed, log and course in our logbooks every hour. We decided that the watch leader at the end of each three-hour watch would plot our Estimated Position (EP) so we would have a rough idea where we were. If we were lucky, we would be able to use our sextants at least once a day to calculate the position of Pelagic Australis.
For the first few days we found it really hard to trust our calculations; all we could do was compare our fixes with each other. After two days of sailing, we dropped off the Falkland Islands’ chart. Now we had to use a plotting sheet; our chart of the South Atlantic Ocean wasn’t detailed enough. With only four sextants on board, working out our position turned into a bit of a competition, especially on overcast days when the sun would only peek out through the clouds for a few minutes.
Once sightings had been taken, there would be a mad rush to the saloon, where the table would quickly become covered with papers, notebooks and almanacs. Once everyone had worked out their second fix, we compared our outcomes and worked out an average, giving us our position. We drew this onto the plotting sheet and continued to carry out our three-hourly EP. This method seemed to work pretty well. When we finally saw the sun after two overcast days, our calculated fix was only 10 miles out from our EP. This gave us confidence that our fixes and EPS were pretty accurate. When we compared our fixes with each other, they were also getting closer together.
These days we can use our phones to get our position on this earth, accurate to a couple of metres. Navigating by the stars, sun, moon and planets is a lot slower and less accurate. By the time our position had been calculated and added onto the chart, an hour later, time had moved on and so had Pelagic Australis’s actual position.
An estimated three days out from Tristan da Cunha, the forecast gave us one day of wind on the nose followed by two days of wind on the beam. A few days later, we were still bouncing into the wind and waves. To stay on schedule, we started the engine.
During my nightshift, I drew in the shape of Tristan da Cunha onto the plotting sheet. This gave us
With only four sextants on board, working out our position turned into a competition
something to aim for, although we all knew that even if we managed to find the island, there was no guarantee we would actually set foot ashore as Tristan da Cunha has no protected anchorage.
Not long after, we received an email from our instructor Alan, who was now back in the UK. ‘Well done guys, you have made it to Tristan da Cunha!’ he wrote.
We laughed and wondered about sending a reply asking him if the island was to port or starboard, as we hadn’t found it yet! But then it all happened at once. The wind changed to the south-southwest, and as we turned off the engine to sail again, we detected some small speckles on the radar, 32 miles away. These speckles were exactly where we expected the islands to be. Now, we just needed to be lucky and hope that the anchorage was protected enough from the swell so we could land.
MAKING LANDFALL AT FIRST LIGHT
At 0600, I was woken up for my next watch. I climbed out of my bunk and noticed a gentle rocking. We were lying hove-to about 500 metres from Tristan da Cunha. I started to make out the contours of a mountain. Closer to the water I could see a string of streetlights, decorating the island’s houses like a Christmas tree. After navigating by the sun, moon, stars and planets for 2,200 miles, we had reached Tristan da Cunha. What an achievement!
Slowly, the sunlight pushed away the darkness, revealing the island’s steep cliffs of black volcanic rock shooting out of the sea. On the north of the island are the homes of the island’s 250 inhabitants. We lifted the anchor out of the forepeak and connected it back onto the anchor chain. Once secured in the volcanic sand below, we inflated the dinghy and motored over to the tiny entrance to Calshot Harbour. High above us, a group of locals watched our arrival at the island’s capital, Edinburgh of the Seven Seas. We were welcomed with handshakes and followed the local official to the information centre, which also functions as the island’s post office, souvenir shop and coffee shop, to get our passports stamped. Walking up the hill, we passed many houses and walls constructed from volcanic stones, probably the only resource which didn’t need to be shipped in from overseas.
All the locals were very friendly and said ‘Hi’ or stopped to chat with us. We learned the next ship wouldn’t be arriving for another few months. The crew walked around the village, glad to stretch our legs after two weeks at sea, and passed a sign which read: ‘Welcome to the most remote inhabited island in the world’. Once everyone was back on board, we set the sails and pointed the yacht’s bow towards Cape Town. After navigating to Tristan da Cunha, Cape Town didn’t feel like a challenge anymore.