We knew it was serious when the skipper swapped his shorts and wellies for a full set of foul-weather gear, writes Theo Dorgan

Well, you can't go to sea and not expect a blow, and you certainly can't go to the South Atlantic in winter without getting a tap on the shoulder. We shouldn't have been surprised two nights ago when a calm 40-knot, slightly lumpy night sail segued into a full-blown Force 12, settling at Storm Force 10, in the space of a night watch. Our night watch, as it happens.

We watched the bar drop, we watched the wind start climbing, and Kevin, our imperturbable watch captain just said, "okay, call the skipper; this is a bit of a nasty." This on a boat where 40+ knots is routinely described as "a bit breezy". Steve came up having checked out the weather on the satellite photos and said simply, get everything out of the way that isn't secured - this looks dirty. That wasn't in itself so alarming; what worried us was that he had swapped his normal attire of shorts over thermal tights shoved into bright orange wellies (with blue soles) for a full set of foul-weather gear. Then we knew it was serious.

It blew all night, and all the next day, and even in our bullet-proof boat, designed for the rigours of Antarctic expeditions, I began to have my doubts. Howling doesn't even begin to describe the wind, and to say the waves were eight to 10 metres, as high as an average house, doesn't even begin to describe the effect of an endless succession of grey, foam-streaked mountains hurling themselves endlessly against the hull.

The ones coming over the bow and sweeping the pilothouse, or the quartering waves that smashed across our stern, these weren't too bad. They, at least, were regular. You could brace against them. It was the ones that hit us broadside on, like a couple of tons of wet concrete, with no warning, that got our attention. One rolled us over on our beam ends, and sounded like the crack of doom. In that kind of weather - and we had it from then for the next 36 hours or so - you want to run off, let the schedule go to hell, and just wait for it to blow out. Unfortunately, we had a schedule we couldn't blow off, things to deliver to Tristan da Cunha, so that wasn't an option.

We were also unlucky in that, to avoid falling into either of two nasty weather systems, Steve had been stealth-sailing, slipping neatly between the worst of the winds, holding our boat speed back so that the notorious Tristan swell would have faded when we got there. Put it all together and you get the kind of experience we had all anticipated when we signed up for this; when it came, believe me, there wasn't a soul on the boat who was happy about it. And yet, everyone stayed cool, everyone did what was needed. And we were brilliantly led.

This morning, when we came up on Tristan da Cunha in bright sunlight, we all felt it a landfall well deserved. There is something primeval about weathering a storm, something so near to the heart of the human experience, that the metaphor never tires, is found in all cultures and in all times. So, too, with the qualities needed in an ocean-going sailor: discipline, fortitude, patience and the will to prevail. I never met a sailor who didn't take care not to anger the wind gods, never encountered a more sober or more superstitious profession. Some curious prayers were said in the past 48 hours, be sure of it.

So, calm after storm, Tristan in the light of dawn, a great volcanic mountain with a cluster of bright-painted houses at the water's edge. And, because the architect of things has a sense of humour, a great rainbow arching over all. Just like the one we sailed through rounding the Horn, so long ago now.

We have few illusions about this southern ocean at this stage, though. It looks calm and beautiful today, paradisal, but out there ahead of us is another blow, the electronic soothsayer says so. We'll not be lulled into inattention. So, clean ship, ashore for a few hours, gather our breath and out into the last leg of the journey.

Nothing this ocean might do would surprise us now. A brisk northwesterly all the way into Cape Town, a fast run in a good boat, that would be nice, but it isn't up to us. We've taken a tough one, we'd rather not take another but if that's the way it has to be, we'll do our best to be ready. We're homeward bound: you can sniff it in the air, sense it in the way people withdraw into a staring silence. We're in no mood to be deflected. Homeward bound and not inclined to mess around.