The owner of a boat that sparked South Australia’s largest search operation has explained what led to him and a friend going missing for four days in the Southern Ocean.

Tony Higgins, 57, and Derek Robinson, 48, were found by police yesterday off the state’s south coast after being reported missing on Sunday.

They left Coffin Bay, on the Eyre Peninsula, last Thursday, on their way to their hometown of Goolwa, on the Murray Mouth.

They were sailing a 10-metre wooden-hulled fishing boat called Margrel, which Mr Higgins bought as a restoration project.

On Monday, police said they had “grave fears” for the men’s safety and described the Margrel as a “somewhat dated” riverboat that would struggle on the rough ocean between the Yorke Peninsula and Kangaroo Island.

Police found the vessel on Thursday morning and towed the men back to Victor Harbor, but Mr Higgins has stayed on the boat, moored off the Granite Island causeway, to make sure it does not sink.

Tony Higgins on board his boat Margrel at Granite Island. Photo: ABC

Mr Higgins said he had travelled to Coffin Bay to check out the boat, and then decided to buy it.

He said he knew “a thing or two about wooden boats” – Goolwa is home to a wooden boat festival – and planned to restore it.

“It’s a very seaworthy boat – a very seaworthy vessel – so we dragged it out of the water, straightened its bum and cleaned all the muck off it, went over it, put a bit of caulk here and there where it needed it and loaded it with stores and then off we waddled,” Mr Higgins told ABC Radio Adelaide.

About 120 kilometres into their journey, near Port Lincoln, the boat hit either a turtle or a submerged log and one of the propeller’s three blades broke off.

They then slowed down from about 7 knots (13 kilometres per hour) to between 2 and 3 knots, extending their planned journey from four days to eight.

“We just tinkled along and made do,” Mr Higgins said.

The Investigator II police boat finds the Margrel on Thursday. Photo: ABC News

Swell ‘nothing like a cyclone’

They never noticed the aeroplanes searching for them from Sunday to Wednesday, and only encountered one other boat, in the Investigator Strait.

Mr Higgins, who once worked as a fisherman in the Gulf of Carpentaria, said the waves and wind was “nothing like a cyclone” he had been through up north.

“It was rather large swell but I felt safe,” he said.

“My deckie [Mr Robinson] hadn’t been doing this sort of stuff before, but after a while he saw how the boat was travelling and felt all right about it.

“He got a bit seasick, which wouldn’t surprise anybody, but I never felt unsafe at all.”

Derek Robinson hugs his grandson after being rescued. Photo: ABC News/Claire Campbell

No alert because they were ‘not lost’

The search covered more than 120,000 square kilometres, with help from the Australian Maritime Safety Authority, the Royal Australian Air Force and Kangaroo Island and Volunteer Marine Rescue, as well as police.

The Margrel did not fire off any flares or activate its Emergency Position Indicating Radio Beacon (EPIRB), leading police to suspect it did not have the emergency gear on board.

But Mr Higgins said that was because they did not consider themselves lost and had “back-up plan on back-up plan on back-up plan”.

He was fined $1,000 for having an out-of-date EPIRB and for only having expired flares on board.

The search area for the missing men off SA’s southern coast. Photo: ABC/SA Police

SA Police also discovered he did not hold an appropriate recreational boat licence.

Mr Higgins thanked everyone for trying to find him and his friend.

He said they only realised people were worried about them when their phones “went into meltdown” as they returned to mobile coverage off Encounter Bay.

“Sorry Australia!” Mr Higgins said.

–ABC