Paloma Werner has a whale of a tale to tell after the mast and rigging of her sailboat were smashed to smithereens by a breaching southern right whale.

Werner and Ralph Mothes were sailing off of Cape Town, South Africa, last weekend when they spotted a playful whale breaching the surface of the ocean.

They were about 200 metres from the mammal, and decided to keep their distance and watch the "spectacular" show, she told CTV News Channel on Thursday, from Cape Town.

"The next time he came up again he was half the distance, about 100 metres from us, and Ralph said to me 'surely he's not on a collision course with us,'" Werner said.

They had heard of instances where whales come close to a sailboat, then dive underneath at the last minute, so she got into position to capture a photo of the whale as it passed underneath the far side of the boat.

Mothes was steering the sailboat, which was running on wind power with no engines.

"I just heard him say 'oh shoot,' and I look around and see this massive whale coming out of the water, and banging against the mast, and slipping back into the water. And it was like slow motion, the mast with the rigging, with the sail, everything coming towards us," she said.

"Ralph stuck behind the wheel and I stuck behind the doghouse and that's how we were lucky we were not hurt."

Mothes said the moment was caught on camera by a tourist in another boat.

According to some reports the sailors were aggravating the whale by getting too close, and the collision may have been an angry retaliation by the mammal.

Werner flatly denied the allegation, saying it was nothing more than an accident.

"It was a complete fluke," she said. "The whale did not hear us. It was a young southern right whale and they have not very good eyesight and they lead themselves by sound. We were sailing and it didn't hear us, it was just having a nice time breaching on a Sunday and happened to hit us."

She added: "The whale was actually coming towards us. We were sailing away from it and it was coming towards us."

The collision caused extensive damage to the sailboat, which is currently undergoing repairs in Cape Town. Werner said they hope to have the yacht back in the water in about a week.