Sirena just introduced its first 58 designed for the U.S. market at the recent Fort Lauderdale International Boat Show, a German Frers-designed semi-displacement cruiser built for performance and easy living. The interior, by Tommaso Spadolini, is filled with natural light from large windows; the main deck is on one level to make moving around easy. Explaining the appeal of the Turkish-built yacht, Constantinos Constantinou, the head of Sirena’s North American operations, said, “We’ve seen that the  priorities of U.S. yacht owners have changed in recent years. Build quality is considered a given, but yacht owners are now putting much more…