Surfing became Ms Vujcich's lifeline after the former criminal lawyer suffered burnout and was diagnosed with chronic fatigue syndrome 10 years ago.
"There's something about the water, it fills me with joy," she said.
Chronic fatigue syndrome is a debilitating condition characterised by severe fatigue, usually impacting on all areas of a person's life.
"When I can get out of bed, I love surfing. It's keeping me alive."
Ms Vujcich looked at entering the weekend's competition but was dismayed there was no seniors' category for women, as there are in other countries.
Then she consulted the International Surfing Association rules, which said she could in fact compete with the men. So she signed up.
"It's been a tough, tough battle. When the news came back from International Surfing Association, honestly, I was over the moon."
Ms Vujcich said the lack of a senior women's category had put other women off contests.
"No older woman wants to compete against young surfers," she said.
"I think because no women have been allowed, they've been oppressed, they've given up."
The women's open longboard category is open to girls and women of any age.
"It's just so significant. It's the surfing competition where the women have been able to take part with the men."
Ms Vujcich said she was not worried if she won: "It's not for the money, it's for the love of surfing."
Ms Vujcich said as she paddled out, some of the men did not realise she was competing with them and told her to surf elsewhere because there was a competition on.
Surfing New Zealand contest director Ben Kennings said Ms Vujcich's request to compete in a seniors' category was the only one they had received.
"There's not really the demand," Mr Kennings said.
"We can barely get enough in the open women's, let alone over-50s. Generally they [women] like to surf but not to compete."
Categories of the 2016 Coast Papamoa NZ Longboard and SUP Open were men's open longboard, women's open longboard, over-40 men's longboard, over-50 men's longboard, logger division, starboard men's SUP, starboard women's SUP and starboard King of the Waves.