What began as a jovial fishing trip for Kim Thomsen and two other men turned into a living nightmare after a rogue wave capsized their vessel off the west coast of Australia.

The 49 year-old Dane, who has lived in Australia since emigrating there with his parents in the 1980s, was spotted by a 7news station helicopter reporting on the rescue search 20 hours after being washed overboard off the coast of Leeman, about 270 kilometres north of Perth.

An exhausted Thomsen was found floating on his back, stark naked, frantically waving to the news helicopter while a large Hammerhead shark circled only 20 metres away. But there was nothing the news chopper could do except hover close to Thomsen in order to keep the curious sharks at bay.

Fortunately for Thomsen, a rescue boat soon pulled up next to him and although initially he was too tired to even notice it, he was finally yanked aboard before collapsing in a heap while being seen to by rescue workers.

“He's just happy to be with us and with his family,” inspector Peter Foley of the Mid West-Gascoyne District Office told The West Australian newspaper.

Thomsen’s two fishing compatriots have not been as fortunate. His 23 year-old nephew, Sean Coffey, is still missing while Coffey’s friend Bryce Weppner, also 23, has died in a hospital after being found floating unconscious in the ocean.

Chances of finding Coffey alive are rapidly decreasing and rough weather has forced rescue workers to suspend the search for now, but authorities are still holding out hope.

"Naturally, a person in the water this length of time is gonna have a massive impact on his conditioning, but we are hopeful that someone is out there," Foley said.