You'd expect sailing to be an emissions-free sport, but what about the chase boats? This year, each of the America's Cup support vessels were powered by several big petrol-guzzling outboards, generating about 1000 horsepower per boat just to keep up with the space-age foiling yachts. But next time around, Team New Zealand wants them to be powered by green hydrogen. It's working with a Christchurch company AFCryo to develop the emissions-free technology. Max Towle asks Team New Zealand's chief executive Grant Dalton about the push for change.