Imagination can be a terrible liability in a difficult situation. Think the worst and it could very well happen - which is why it is often said that risk-takers have little or no imagination at all.

Take Tony Bullimore, the Southend-born sailor who spent five days last January in an upturned yacht in the Southern Ocean. The amazing response by the Australian navy and marine emergency services will probably go down as one of this century's greatest rescues. Yet his own description of the first few terrifying hours spent in his heaving tomb is almost shockingly bland.

There he was, over a thousand miles from inhabited land and the nearest shipping lanes in the most hostile waters. "At the arse-end of the world," he wrote. The boat might not sink, but he had lost his keel, which meant the craft had no hope of righting itself. Panic? Distress? Uncontrollable tears? No, the solo skipper just rolled a cigarette, nibbled a biscuit and thought "bloody hell - what a mess". Shades of the advertisement for Hamlet cigars . . .

The 56-year-old had already been at sea for two months, as a competitor in the arduous Vendee Globe single-handed round-the-world race. It is acknowledged to be the longest and most challenging yacht race ever conceived, and Bullimore had had his share of bad luck by then. There was a problem with a fuel line which poured half of his diesel supply into the engine room. Then the instruments feeding information to the automatic pilots came apart, which meant that he had to return to the race start at Les Sables d'Olonne on the French west coast for repairs and fuel.

The setbacks put his 60-foot ketch some 1,000 miles behind the main fleet on the 25,000-mile course. Yet he also knew that in the previous race, four years before, the sailor who came third had been forced to turn back early on with keel problems, and had also lost a mast about 1,500 miles from the finish. All Bullimore really wanted to do, he says, was to complete the course: anything could happen en route.

When it did, he was listening to Bob Marley on cassette. He had been trying to slow his boat down, as he was surfing along in a storm at ridiculous speeds. Designed to race, his craft, Exide Challenger, was not built to sustain hurricanes and continuous heavy weather. The hull was vibrating badly when he heard the crack, which sounded like someone snapping a fence-paling across their knee.

Back at the Maritime Rescue Co-ordination Centre (MRCCC) in Canberra, Australia, his was one of two boats which reported serious difficulties by satellite emergency beacon: the Frenchman, Thierry Dubois on Pour Amnesty International was also in trouble. Less than a week later, both competitors became public property as news of their dramatic rescue became the real "circumnavigation".

A "washing machine from hell" is one of Bullimore's more refreshing descriptions in this account of the nightmare - a nightmare of hypothermia, dehydration, frostbite and the loss of a fingertip. Technical detail is simplified where possible for non-sailors, but the reader's confidence is shaken early on in the text with an erroneous reference to megahertz, rather than wattage, as a measurement of radio power.

The hell experienced by his wife, Lalel, back home in Bristol, is well articulated, but the yachtsman's telepathic conversations with her become a little irritating. The real story may have been better told by the skipper of the Australian navy ship who steamed his vessel further south than it had ever been before, without knowing whether he would find bodies or survivors. Tony Bullimore's incredible resilience did allow the world to smile and step a little lighter. But without the heroic efforts of the Royal Australian Air Force pilots, the naval ship, HMAS Adelaide, and the MRCC in Canberra, it might all have been in vain.

Lorna Siggins is Marine Correspondent of The Irish Times