Dennis Conner's Sail America challenge from the San Diego Yacht Club was hanging by its syndicated thumbs until a little more than a year ago, when it hired an expert to organize a marketing campaign complete with video presentations. By appealing to corporate patriotism and, ironically, by bearing down hard on the theme of Conner as a winner, the syndicate has signed up seven major sponsors, each of which has contributed between $500,000 and $2 million. The toughest to land was Anheuser-Busch, brewer of Budweiser berr, which allowed itself to be wooed for 10 months before relenting in May. Sail America's marketing director, Charles Ward, claims to be within $3.5 million of his syndicate's $15 million budget, which is fortunate because Conner has ordered up four 12-meters, all christened Stars & Strips, in his search for the perfect boat for Fremantle.