Police have called off the search for two brothers-in-law who went missing while fishing off Cape Jervis, south of Adelaide, on Sunday.
A helicopter carried out a final grid search of the area on Wednesday morning, but did not locate the men or their 4.6-metre half cabin boat.
Police believe the boat has sunk.
Olive oil producer Vince Scarfo, 44, and grape grower Luigi Palombo, 48, were reported missing on Sunday night, after failing to return from a fishing trip that morning.
A life jacket, torch, bucket and foam were found on Tuesday, while an esky and fuel tank were found on Monday about 6.5 nautical miles northwest of Cape Jervis.
Police say a thorough search of the area was made by helicopter, fixed-wing aircraft and boats.
Inspector Gus Sickerdick later said it was a tough decision to call off the search, but it was made after speaking with experts and the families of the men.
"While the sea and rescue search is over, the police investigation is not and I would urge any boaters in the area who find anything on the water or shoreline which may be related to this incident to call police," he said.
Insp Sickerdick praised the efforts of the families of the men, and the strength and support they had given to others in this difficult time.
He also thanked the volunteers involved in the search which, on a rough calculation, covered more than 2500 square nautical miles.
