There was the Super Nova 60, the world’s first carbon neutral megayacht. Then there was the 72-foot Emax Excalibur, which represented the first step in the maritime industry towards the production of post-carbon yachts. But forget about those – the folks at Sauter Carbon Offset Design and their building partners Ned Ship Group say the latest in their series of green yacht concepts is “the fastest and greenest superyacht in the world.”