While Alexandra and Molly joined forces in the 49erFX only this year, their families have long been close friends.
"They're from Tauranga, so when they came up to Murrays Bay for regattas they would always stay with us, and when we went down there we would stay with them. So I've known Molly for a long time and it really helps with our relationship on the boat," said Alexandra.
Their strong understanding was evident with the pair enjoying immediate success in the 49erFX, picking up bronze in the European Championships in Denmark in July, before making history as the first world champions in the class with a gold at the world championships in Marseille.
While their sisters have teamed up in the 49erFX, Andy and Sam are in the more complex position of being friends, training partners and rivals.
As the country's No 1 and No 2 ranked Laser sailors respectively, the pair will be vying alongside Thomas Saunders for one spot to represent New Zealand at the Rio Olympics. Andy was 11th at this year's world championships, while Sam was 13th in the highly competitive class.
Andy said it is sometimes difficult being both teammates and competitors, but the group all understand the benefits of training together.
"One of the best things about the Laser class is that we're a tight group. It is really competitive when we're out on the water, but we also realise to get better than everyone else we need to work together," he said.
Most of the NZL sailing team will be in action on home waters early next year in the Sail Auckland regatta at the Royal Akarana Yacht Club.