Australian sailor Deirdre Sibly found dead on yacht off South Africa amid fears of pirate attack

An experienced Port Lincoln sailor and her companion have been found dead on their yacht near Madagascar, sparking fears of a pirate attack.

Deirdre Sibly was found dead off South African coast. Pic: Sarah Mack - Facebook.

A Port Lincoln woman has been found dead on her yacht off the coast of South Africa.

Deirdre ‘Cookie’ Sibly was sailing with a travel companion, Pascal, near Madagascar, when they issued a distress signal on Thursday.

Local authorities and nearby ships came to their aid but the pair were found dead on board – and her family fears that they may have fallen victim to a pirate attack.

Ms Sibly’s sister Sue Good said she knew the risks, with the South African seas among the world’s most dangerous.

“It isn’t a very safe place in the world to be sailing. She knew that,” Ms Good told 7NEWS.

The Department of Foreign Affairs has not yet linked their deaths to pirates and authorities are still investigating the circumstances.

Ms Good told The Advertiser that DFAT has not released any other information and the family will wait in Australia for authorities to complete their investigation.

Deirdre Sibly was found dead off the coast of South Africa. Picture: Sarah Mack/Facebook.

Ms Sibly’s yacht. Picture: 7NEWS

An experienced sailor, Ms Sibly had been travelling across the Indian Ocean since June, sailing in the waters off Reunion Island to Tanzania and towards Durban, South Africa.

Close friend Sarah Mack paid tribute to Ms Sibly, remembering her as the “ultimate adventurer”.

“‘Cook’ never let the grass grow under her feet. She took all life had to offer and ran toward every opportunity with unbridled energy, joy and enthusiasm to explore, to learn and most importantly, to have fun,” she wrote on social meida.

“The most excellent bonus mum, passionate teacher, ocean advocate and seasoned sailor. I loved every second I spent with her.”

Ms Good said her sister was “full of life”.

“She was a very special person... everyone loved her,” she told 7NEWS.

Originally published as Australian sailor Deirdre Sibly found dead on yacht off South Africa amid fears of pirate attack