British tourist Lynette Hartman, 55, has spoken about how she survived the boating accident in Cape Town's Hout Bay, in which two people died and 24 were hospitalised.
Mrs Hartman was trapped inside the hull of the 36ft whale-watching boat The Miroshga, for three-and-a-half hours before she was rescued.
She shared the space with two other female tourists and British RAF veteran Peter Hyett, who died before they were rescued.
The Daily Mail reports that Mrs Hartman and two other South African women, Bronwen Armstrong and Anna-Marie Wever, survived only because they found an air pocket in the hull of the catamaran.
Mrs Hartman was on holiday with her husband, Colin, and their son Matthew, 27. They were also on the boat but were rescued. Mrs Hartman was treated for hypothermia and temporary blindness caused by diesel fumes.
According to the Daily Mail, last week she told her mother Joan that she had lost hope of being rescued. She said: "I thought I might not make it, and that help would never come. I just had to keep kicking to stay above the water and pray someone would come. At last they did."
She said: "There was a small space, like a cupboard, where lifejackets were kept, and there was an air pocket. The water was so cold, I knew I must pull myself up into that space."
She added: "The British lady was curled up in a ball, with her feet in the water. She was very panicky. She was holding her knees by her chest and crying.
"She was wearing shorts and she just kept saying that she was so, so cold.
"She screamed out for help. In fact, she was screaming so much I had to tell her to stop because otherwise she'd use up all our air. We held each other's hands the whole time. I held the British lady's hands so hard that she said I was hurting her."
The three women banged on the inside of the boat's hull with an old aerosol can, and eventually gained the rescuers attention. Rescuers then had to persuade Lynette and Anna-Marie to remove their lifejackets so that they could swim down and clear of the hull.
Bronwen Armstrong and her fiance, Caspar Kruger, explained that the accident happened when one of the boat's engine's failed. The boat then turned around to face shore, so that one of the crew could go to the back of the boat to fix it. That's when a huge wave landed on the back. The second engine then failed and a second wave hit. The Miroshga then started to sink.
Bronwen said: "The water was coming in very, very fast and people were screaming, shouting, 'We're going to sink! We're going to sink!' A bigger boat came and some people jumped off. As they did, another big wave came and the Miroshga flipped over. There was panic."
iol news reports that the wife and daughter of Welsh tourist Peter Hyett, who died in the accident, have written to thank the City of Cape Town for its help after the accident.
In a letter Suzanne and Linda Hyett, who were both safely rescued, wrote: "We will always remember the relief we felt as you swam towards us and took control of the situation, thank you thank you. We would also like to thank the South African disaster team who have supported us throughout and still support us until we can return home."
British woman survives in air pocket for two hours
Man dies and two missing after yacht capsizes in Spain