Vixen… ''coquette, flirt, temptress,'' my thesaurus says, ''siren, tease, vamp, seducer.'' And so she is: Vixen II, the most sensuous racing yacht in the Med. The sight of her under full sail causes lovers to swoon and hardened yachtsmen to go weak in the knees. The 78-foot Edwardian schooner was once the darling of Newport's sailing society, playing host to Kennedy’s, Morgan’s and other American royalty. One off the famous owners was moviestar “Warren Beatty”. All mahogany and teak, with gleaming brass and crystal accents, Vixen II is appointed with nautical textiles, fine stemware, silver service and Royal Doulton china. Yet she's anything but frilly, exuding a masculine energy worthy of her treelike 78-foot mainmast. But insiders say that when she opened for charter last summer for the first time in more than 20 years, she is the most romantic ship in the east Mediterranean sea.