"I inherited the flag pole from my father – it is about 100 years old," he said. "I usually fly the New Zealand flag, but my dad used to fly the Jolly Roger when the kids returned home.
"My daughter returned home from university recently, so I thought I'd follow in the family tradition."
A jovial Nash played down the notion he was planning an attack of his own.
"It has nothing to do with the America's Cup, nothing to do with any dark, deep conspiracies and I'm not planning any pirate-like coups," he joked.
"It is just a bit of fun," he said.
"I've also got an 8-year-old son and we've been reading a lot of pirate stories recently. It mentions the Jolly Roger and I promised to put it up when his sister came home."