A man has had a lucky escape after his small metal dinghy capsized off Western Australia's coast, in a 'thousand-to-one' chance of a rescue boat being in the same area at the same time.

The Geraldton Volunteer Marine Rescue were escorting a group of four long-distance rowers out of a shipping channel in Geraldton, 415km from Perth, when they spotted a flare.

A minute later they had pulled up next to a man named Murray who was clinging to his upside-down dinghy, waving a smoking orange flare.

Volunteer rescuer Jamie Jones spotted Murray and the crew immediately went to help him.

"Once we have seen the flare we were there within the minute," he said.

"We shot across and got him out of the water within five minutes, and then spent another hour trying to get his boat towards shore for him."

Murray was shivering when he was brought on board, but otherwise in good condition.

He had been in the water for more than an hour and Mr Jones said it could have ended badly for the fisherman.

"He definitely needs to buy a lotto ticket," he said.

"For us to be out there at the end of the channel and just happen to be panning around to turn home and he let a flare off at that instant — there was a thousand-to-one chance we would actually see that flare and we did."

Murray is a lucky man, after he was found clinging to his small metal dinghy in Geraldton's shipping channel. ( ABC Midwest and Wheatbelt: Laura Meachim )

Perfect luck

If a boat had not been in the near vicinity, Mr Jones said it would be unlikely Murray would have been seen from the shore.

"Today you would struggle to see the flares from the land," he said.

"Just because of the haze on the water, it was just lucky he let a night-time flare off that we happened to see it."

Rescuers spent an hour trying to retrieve Murray's boat before bringing it into shore. ( ABC Midwest and Wheatbelt: Laura Meachim )

Murray said he was grateful to his rescuers.

"Great job, much appreciated," he said.

"I knew someone was coming eventually but it was getting a bit cold."

While it was a choppy day on the water, the crew successfully managed to turn Murray's boat over and bring it back to shore where his worried wife was waiting.