How do Polynesians rate on spatial intelligence tests? They were eyeballing star patterns instead of using navigational tools like the Europeans, right? So they were doing the math in their heads.
I don't think it has anything to do with racial differences in specific kinds of intelligence. I really just think it's a matter of practice makes perfect. If your entire culture is based around seafaring then you've created the perfect environment to foster a tradition and cadre of good navigators, and that's what they got.
I didn't see anything in the article or other things on polynesian navigation that indicated they used mathematics. To determine longitude by the sun and stars, an accurate chronometer was still necessary.
Your comment is a little ambiguous--- we've built modern-day catamarans that can definitely sail upwind. I think you're saying that the catamarans that Polynesians have built were never able to go up wind.
The small catamaran I sailed as a teenager had no problem tacking upwind. I don't believe they're inherently any worse at this than a single-hulled craft?