Pretty much everything has had a crack at killing bankrupt multimillionaire turned desert island castaway David Glasheen. It goes with the territory, living solo on far north Queensland’s Restoration Island for 22 years.

There’s hulking saltwater croc Boxhead, who’ll take a chunk out of any unsuspecting idiot. There’s sharks everywhere. And venomous taipan snakes that claimed his first island dog.

Cyclone Ingrid, which bore down on Resto mercilessly in 2005, had a crack. It nearly drowned Glasheen as he struggled to tie up his vital tinny and almost whipped apart his shack.

But the biggest danger isn’t anything as dramatic. It’s the coconuts.

“They’re by far the most dangerous,” the castaway insists when we meet at a cafe on a rainy Melbourne day that to Mr Glasheen feels every one of its 3500-odd kilometres from Resto, off the coast of Cape York not too far from Papua New Guinea.

“They are high up and very heavy and they’ll brain you if they fall on your head.”

The heads up about coconuts is just one snippet to emerge in Mr Glasheen’s eccentric memoir The Millionaire Castaway.

Often he’s naked at home on the island but today the 75-year-old is in chinos and navy blazer that hint at his former life.

Once the director of a gold mining company prospecting in Papua New Guinea and with a waterfront home in Sydney’s Palm Beach, Mr Glasheen didn’t plan to leave it all behind. But the stockmarket crash of 1987 wiped out his $13 million fortune overnight, as shares nose-dived from $1.40 to $0.02. His house was repossessed, and his wife left soon after.

Trying to claw his way back, nothing worked. The only release he could find was in the surf.

“There’s nothing better than rough water to clear your head up,” Mr Glasheen says.

“It’s the adrenaline that gets you on your game again, so moving to the island came naturally.”

Initially floating the idea of turning Resto into a luxury resort, he and some friends took on a 50-year crown lease that expires in 2039. But the island got under his skin and he shook off development plans like his corporate clothes.

Now there’s no way Mr Glasheen would move back to the rat race.

“To me, a city is like an unfenced prison,” he says.

“The closer I am to nature, the more I can think. And the clearer you think, you start to see the things you never saw before.”

Mr Glasheen lives off the island’s bounty and fishing. Maintaining a modest bank account to receive his pension, he makes an annual trip to Cairns, and stocks up on staples via monthly trips to Aboriginal community Lockhart River 40 kilometres away, via dinghy then car.

He barters with passing fishermen and cooks on an open fire or a gas-run camp stove. There’s electricity for night lights and a beer fridge, run though solar power with a back-up generator.

“The satellite phone’s pretty sketchy after lightning took down the Telecom tower in Lockhart River 18 months ago,” he says, but loneliness isn’t a problem with whip-smart dingo Zeddi by his side.

“On the island, you’ve got nature for company. I never get sick of watching the water, the birds or the fish, because it’s alive,” Mr Glasheen says.

“You can be really lonely in a city full of people because you’re not connected to them. They’re like robots.”

Visitors are rare. The most memorable was Gladiator star Russell Crowe in 2003, who dropped in while passing by on a chartered yacht on  honeymoon with then-wife Danielle Spencer.

Mr Glasheen didn’t recognise Crowe at first: “He was really down to earth, but I thought he might have been a tennis player.”

They talked about movies, family and Indigenous rights, getting drunk on multiple bottles of Bowen Estate Cabernet Sauvignon.

Mr Glasheen is a dedicated reader after long days working the island. The most important task is ensuring the boat’s secure.

“Without that, I’m in a pickle,” he says. “There’s nothing better than going to sleep to the sound of the ocean and the wind whistling through the sheoaks.”

The Millionaire Castaway by David Glasheen with Neil Bramwell, is out now, published by Affirm Press.