Casper, on the other hand, enjoyed the adrenaline of sailing out on the water.
Like his sister, he has a competitive streak.
"I like being busy in the natural environment, and particularly planing - it's exhilarating and it gives you a kick. When you get a really good start at the pin end, it's the thrill of being ahead of the fleet."
Their competitiveness extends to each other and can quickly lead to arguments. In fact, when asked about their arguments, they begin arguing over their response.
"If I've done something good," Astrid says, "then Casper will try and say he's done something better.
"Our grandmother finds it difficult when we're having dinner."
"We might argue but in fact we do actually help each other more than normal."
Sailing at events such as the Optiworlds together - they agree - gives them a healthy dose of "competitive motivation" and a good understanding of each others strengths and weaknesses.
In the clearest indicator yet of common ground, they also wholeheartedly agree they want to see more of the New Zealand outdoors before they leave.
Astrid explains that although they are twins, she was a year behind in school so they see themselves more as siblings with an age gap. "To other people we're twins, but we feel more like brother and sister."
There is no protest from Casper sitting to her right, so I assume he agrees.
