Police have called off the search for missing sailor Tony Higgins in waters south of Adelaide.

It concludes the third day of efforts by air, on the water and on land to find the 57-year-old boatie.

He and his friend Derek Robinson had been found after the state’s biggest maritime search two weeks ago.

But Mr Higgins went missing at sea on the same boat for a second time, putting out a distress call near Victor Harbor early on Tuesday morning.

Part of the back deck of his boat, the Margrel, equipment from it and a wallet containing Mr Higgins’s identification were found washed up near the Murray Mouth on Wednesday.

SA Police said in a statement this evening that the search has been been called off pending any “further sightings or information”.

The latest search covered about 500 square kilometres of ocean off Victor Harbor, Goolwa and the Coorong.

The police helicopter searches along the Coorong for debris from Tony Higgins’s boat the Margrel. Photo: ABC News

Sea Rescue volunteers, police patrols, water operations officers, the police helicopter and fixed-wing aircraft were all involved in the search.

But the plane and the helicopter could not be used today because of poor weather conditions.

Items police believe are from Tony Higgins’s missing boat the Margrel, found on a beach near the Murray Mouth and taken to the Goolwa police station. Photo: Supplied/SA Police

Earlier on Thursday, SA Police Inspector Gus Sickerdick conceded the length of time Mr Higgins had been missing reduced the chances of him being found alive.

“Obviously, as it goes on, the chances of doing that [surviving] are diminishing,” he said.

“We’ve got to bear in mind the nature of the surf and if he is in the ocean how it is affecting him, if he has got anything to protect himself.”

This evening, police thanked other emergency services for their assistance “in trying conditions”.

They urged anyone who finds any more debris along the coastline to call the Police Assistance Line on 131 444.

–ABC