The world's first hydrogen gas fuel-cell superyacht, long rumored to have been commissioned by billionaire Microsoft founder Bill Gates, is now officially for sale. Dubbed Project 821, the 390-foot (119-meter) superyacht is designed to run on 'green' hydrogen, which is produced by by splitting water into hydrogen and oxygen using renewable electricity. The luxurious vessel features two bedrooms, a gym, offices and numerous bathrooms for a home away from home feel - the makers designed to mimic an upscale apartment. Dutch shipbuilder Feadship said the launch of this approximately $646 million vessel on May 4th at ... (full story)