The 190-foot Royal Huisman Ethereal is one of the most environmentally friendly sailing superyachts to launch in the last few years. It boasts the first true hybrid engine on a sailing ship, a power source that uses motion generated under sail to recharge the yacht’s lithium-polymer batteries and run all functions on battery power for an extended length of time. Royal Huisman installed LED lighting and the latest in flooring and insulation to make the superyacht energy-efficient. Beyond the environmental technologies on board, naval architect Ron Holland engineered Ethereal’s hull and rigging specifically for performance. The boat’s sleek lines look classy with the ketch rigging, but, in fact, its wing keels and long hull have been tank-tested like America’s Cup racing boats to ensure optimum efficiency under sail.