THE French doctor and biologist Alain Bombard achieved worldwide fame in 1952 with a scientific experiment of foolhardy audacity. He set himself to sail alone across the Atlantic in a 15ft Zodiac dinghy in order to show that a human being can survive for weeks if not months by drinking seawater and juice pressed from the flesh of fish.

On December 23, 1952, 65 days after leaving the Canary Islands, he landed his minuscule craft, appropriately named L'Hérétique (Heretic), on a beach in Barbados. He was emaciated and anaemic but still able to walk the two miles to the nearest police station. He had endured terror, solitude, despair, storms and shark attacks. His belief that humans can survive drinking small quantities of seawater was forcefully vindicated. But even more important than water or food, he said, was mental attitude: “The survivor of a shipwreck, deprived of everything, must never lose hope.”

Bombard had been inspired to his research by an experience he had as a junior doctor at the hospital in Boulogne in 1951. A trawler sank in bad weather outside the harbour, and 43 bodies were brought to the hospital. “In spite of all our efforts we failed to revive a single one,” he wrote. “At that moment the full measure of the tragedy conjured up by the word ‘shipwreck’ was brought home to me.”

Bombard moved to the Oceanographic Institute, Mon- aco, to research the nutritional properties of marine creatures and the feasibility of drinking seawater — a practice invar- iably and rapidly fatal, according to conventional wisdom. Although Bombard’s findings were sufficient to persuade fellow scientists that a well-hydrated individual could drink a pint or so of seawater a day without ill effects, seamen at large remained to be persuaded.

Amid scepticism and opposition from every quarter, the voyage of L'Hérétique began to take shape, starting in the summer of 1952 with a series of trials in the Mediterranean. On an 18-day expedition from Monaco to the Balearic Islands Bombard and his colleague, an English drifter called Jack Palmer, had a visitation from an albino whale 80-100ft long.

As the summer progressed Bombard made his way to northern Morocco, and it was from there, in August, that he set off alone in L’Heretique for Casablanca and finally the Canaries, where his great transatlantic voyage began on October 19, 1952. His triumph that December did wonders for the sales of the Zodiac dinghy which became a popular recreational craft.

Alain Bombard was born in 1924 into a medical family in Paris where he was educated and attended medical school. After his epic voyage, which he described in his book Naufragé volontaire (1953, translated into English as The Bombard Story), he devoted much of his time to writing and to irritating officialdom with his unconventional ideas about survival.

In 1958 he attracted unfavourable publicity when an expedition to cross a dangerous sandbar near Lorient in a lifeboat came to grief, with all his eight companions being drowned when it overturned.

Towards the end of the decade Bombard set up a floating marine laboratory, called Coryphène, but ran into financial difficulties. He was bailed out by Paul Ricard, the pastis magnate, who appointed him to direct his new Oceanographic Institute in 1966.

In 1974 he joined both the Socialist Party and an environmental pressure group set up by the Polar explorer Paul-Emile Victor, along with his friends Jacques-Yves Cousteau and the vulcanologist Haroun Tazieff. He served in local government for some years before, in May 1981, being appointed Minister of the Environment. He lasted little more than a month in office, his uncompromising pronouncements on hunting having alienated many in high places.

In the same year he was elected to the European Parliament. There, until 1994, he was a formidable agitator on environmental issues, ranging from nuclear power to the culling of baby seals. His outspoken opposition to force-feeding geese for pâté de foie gras earned him and his family death threats.

Bombard wrote a series of books, including La dernière exploration (1974), Les grands navigateurs (1976), Au-delà de l’horizon (1978), La mer et l’homme (1980) and Aventurier de la mer (1998).

He was appointed an Officer of the Légion d’Honneur in 2000, and was invited to act as honorary president of the international film festival of Dijon in 2002, the 50th anniversary of his voyage in L’Hérétique. The occasion prompted a flurry of media attention, some of it, as always in Bombard’s case, sceptical. One interviewer asked what motivated his conversion to environmentalism. “I had fought on behalf of man against the sea, ” Bombad replied, “but I realised that it had become more urgent to fight on behalf of the sea against men.”

Bombard is survived by his wife, Ginette, whom he married in 1952, and by three sons and two daughters.

Alain Bombard, doctor, politician and adventurer, was born on October 27, 1924. He died on July 19, 2005, aged 80.