The company already has a patent for a such a design
Google seems to be building a massive floating data center close to San Francisco. The construction, sitting on a giant barge, is four stories high and is made up of shipping containers.The building is still underway, but Cnet has gathered some evidence that Google is behind all of it and that it may be a data center. There's been no official confirmation and there's plenty of secrecy about the project.
Still, people working in the area largely believe it is a Google project. The only companies that are officially linked to the project also seem to have a connection with Google.
A few years ago, Google also filed for a patent on a floating data center. The advantages of such a project would be the cheap and efficient cooling, using seawater. The cooling is one of the biggest expenses of a datacenter.
At the same time, the sea would provide a cheap and green energy source from the wave motion.
Google is well known for its data centers, even as it tries to be very secretive about them. It's been talking about the more ambitious projects, the water-cooled ones, the green energy it uses, and so on.
However, it keeps everything else very close to its vest when it comes to what's actually happening inside.