The Google founder Sergey Brin has spent the past few years building up his "Fly Fleet," including the 40-meter Butterfly.

Insider; Marianne Ayala/Insider

In a quiet harbor in California's Redwood City, 30 miles south of San Francisco, there often sits a gleaming 40-meter yacht flying the flag of the Marshall Islands.

The sleek, silver-and-white vessel sits among a smattering of other high-end cruisers, but this boat is a bit different: Butterfly, as the yacht is known, is owned by the world's...

Continue Reading Inside the 'Fly Fleet': billionaire Google founder Sergey Brin's growing flotilla of megayachts, boats, and jet skis