But as Ms Brewster stepped on to land, exhausted by the 247-day marathon, and joined the growing list of champions of endurance, a question loomed. What madness is it that drives so many modern Britons into the eye of the storm?
Ms Brewster said yesterday from the Heath Insured, which would normally carry a crew of 14: "I'm more mad than I thought. It was so hard to keep going, not having anyone else out there. Although I did get a lot of advice from the team on the shore, you're completely on your own out there. So many times I thought: why am I doing this?"
The challenge was put to her at the wedding of Chay Blyth, the sailor who defied sceptics in 1971 by being the first to complete that trip alone.
Ms Brewster said: "Everyone had had too much champagne, and I thought it would be forgotten about once everybody had sobered up."
Instead, last October, she began her odyssey from Southampton accompanied only by her mascot, Gutsy the toy gorilla.
Her cargo included 500 long-life dried meals, tins of spinach, 36 boxes of porridge, six jars of honey, 1.5kg of jelly babies and a bottle of rum.
In the course of her journey, Ms Brewster faced some of the greatest physical challenges.
She almost gave up when the mainsail was damaged as she approached Australia; it took her more than 48 hours to repair the sail, which weighs around a quarter of a ton.
Ms Brewster has followed an arguably glorious but mad British tradition.
As a maritime people, Britons have always been forced on to the waters by their island status and driven to the forefront of naval endeavour and exploration. As knowledge grew and the world became smaller, sailors took up more personal challenges and moved into yachting in record numbers.
In 1898, Captain Joshua Slocum, a Canadian, was the first man to sail solo round the world; then, in 1969, a Briton, Robin Knox-Johnston, circumnavigated it non-stop for the first time alone. In 1973, Clare Francis made a single- handed transatlantic crossing; and Mike Golding set the record last year as the fastest man to sail the wrong way round the world in just 161 days.
Ms Brewster said: "When I felt like giving up, it was my family and friends who saw me through. My brother sent me a letter saying he'd gone through life doing all the normal things and he was so proud his sister had set out to do something like this and could achieve it. That was very special."
According to psychologists, her personality fits exactly the profile of the peculiarly British breed of solo sailors. Ms Brewster, a farmer's daughter, is fiercely self-reliant, and, on her own admission, is intolerant of other people's weaknesses.
Dr George Sik, a psychologist who has worked with yacht crews, said: "Compared to other people, they can be intensely assertive and impulsive, certainly eccentric, though not entirely barking mad. The most surprising thing with Chay Blyth was his lack of organisation and impulsiveness." He added: "There was this sense of 'just get the money together, go off and have a go', which, by any rational standards, is an unusually impulsive way of going about things. That is certainly what separates these explorers from other people."
This impulsiveness is shared by other modern-day adventurers, including the explorer Sir Ranulph Fiennes. He has described how he often forgets to take the right equipment on treks and tends to improvise as he goes along, making things fit his needs along the way.
Ms Francis, now better known as a best-selling crime writer, is reluctant to remember her sailing days. She believes that there is a degree of madness involved in taken on the seas alone.
"It wasn't a sporting thing for me," she said. "It was more of an odyssey and I could never have carried on. For me, the sea is incredibly boring after a while. It just goes on and on. It was a spiritual thing, but it was a very short period of my life."
The tradition of lone voyages has become so established among British sailors that round-the-world trips are relatively commonplace.
Only the speed in which they are completed, or the handicaps that are overcome, make them extraordinary.
Leslie Powles, 70, dubbed the Ancient Mariner, returned from his third round-the-world voyage on Sunday. The four-month trip nearly cost him his life. He went off-air, and friends feared he had been lost at sea.
Despite being knocked unconscious, and running short of food and water he survived aboard his 34-ft sloop, Solitaire. He rationed himself to a quarter of a tin of corned beef and two spoonfuls of rice a day and finally sailed into Lymington in Hampshire at the weekend.
Mr Powles said: "There was water coming in the boat all the time, but I could not move for 24 hours. I just sat there and watched it ...
"I am not going to go round the world again. I think three times is enough and you start to get giddy if you go round more than three times."
However, the courageous folly of Britain's solo voyagers was defended yesterday by John Reed, secretary of the World Sailing Speed Record Council, the official body set up to monitor the challenges to existing records for completing voyages.
Mr Reed said: "People have started to look at it as a challenge to break time records, which is becoming more and more difficult as they get faster and faster. It's a natural part of human endeavour. They're certainly not mad."
He added: "They're extremely keen yachtsmen who are very self-reliant, and wish to prove their abilities, which are considerable. People who are mad in yachts jump overboard or drown."Reuse content