Over six decades, there were more than 50 prisoners desperate enough to try to escape but, despite several super-human efforts, their attempts proved futile.

A few tried to swim. They were doomed to failure due to the vagaries of the tides, offshore winds and choppy seas. And, of course, there were the ever-present man-eating sharks. Some took to crudely-made rafts of driftwood and logs. One man lashed a door to two pine stools. Even a bath tub was tried. One pair planned to swim two horses across the bay with themselves as passengers. They were foiled by an alert warder.

Then there were those who took to boats. One commandeered a whaleboat after slinging the guard into the water. Others discovered boats which had broken loose from moorings on the mainland and had drifted unseen cross the bay into the mangroves at St Helena. Still others tried to break into the prison boathouse.

Some prisoners perished in their attempt. The aborigine, Burketown Peter, clinging desperately to a wooden target-frame used by the warders during rifle practice, vanished beneath the waters of Moreton Bay as his makeshift raft headed out to sea on an outgoing tide.

One of the island prison's most publicised episodes took place in November 1911, when prisoners Henry Craig and David Mclntyre vanished for nearly two weeks. Most people believed they had escaped to the mainland and, as a result, South East Queensland was turned upside down in the search for the pair. Warders turned out each day to search St Helena from end to end. Police and blacktrackers patrolled hundreds of kilometres of mainland coastline, and residents of Brisbane and nearby settlements thought they saw the two fugitives behind every bush and tree.

On the twelfth day the prisoners reappeared. They had been hiding above the ceiling of the tailors' workshop on St Helena, where they had been aided by a prisoner accomplice who supplied them daily with food and water. After the news of their surrender reached Brisbane, the press had a field day. Commented one newspaper:

'The public gripped both its sides with laughter last Thursday morning. It was the anti-climax to the deuce of a hullabaloo and a sensational hue and cry after the two convicts, Craig and Mclntyre, were reported to have escaped from the penal establishment in Moreton Bay to the mainland. For ten whole days the press wove fairy tales and flimsy romances describing in as many different ways how the two desperate fellows had reached the mainland and liberty.

Then came the news that the lost prisoners had never so much as put a foot outside the island since the day they were sent there. It may be unkind to laugh, but it is impossible to repress a smile.'

Most escapees, however, rarely got any further than the island mangroves and scrub where they were captured by searching warders, supplemented, if necessary, by police from Brisbane, or driven out by hunger, or by intolerable hordes of mosquitoes.

In fact, only one man was not recaptured after escaping from the island prison. Notorious gunman Charles Leslie was whisked from the island early one morning in 1924 by criminal accomplices who were waiting offshore in a motor boat.