JUST ABOUT EVERY ANNOUNCEMENT from top yachtbuilders in Europe these days is heralding something that’s never been done or built or tried. ¶ At Amels in the Netherlands, Aurora Borealis, the yard’s first 220, has completed a technical launch and is on track for delivery this summer. The Tim Heywood design evolved from the Amels 212, with a swim platform and beach club that, at more than 7,000 combined square feet, aim to leave all others on the superyacht scene appearing to be, somehow, small. ¶ Meanwhile, also in the Netherlands, Heesen Yachts is on schedule for a January 2021 delivery of the first newly designed hull in its 5000 aluminum class. Project Aquamarine promises an effciency gain of 12 percent with MTU’s 16V 4000 M65L “green” engines, which Heesen…