UPDATE 7/30/14 Maui News offered the answer (and a better picture) today. It is the Hamilton A. a private yacht owned by Russian Billionaire Andrey Melnichenco
Spotted this afternoon in Maalaea Bay,(7/30/14) outside the small boat harbor was this white vessel at anchor, seeming a bit too large to enter. The KCA camera was overwhelmed with the distance from North Kihei Shoreline, in spite of the immensity of the yacht. Can you I. D. it?