Microsoft project "Natick": an underwater datacenter
Main target: cost-efficient cooling.
The pilot consists of giant steel tubes linked by fibre optic cables placed on the seafloor.
A Microsoft research project to manufacture and operate an underwater datacenter. The initial experimental prototype vessel, christened the Leona Philpot after a popular Xbox game character, was operated on the seafloor approximately one kilometer off the Pacific coast of the United States from August to November of 2015. Project Natick reflects Microsoft’s ongoing quest for cloud datacenter solutions that offer rapid provisioning, lower costs, high responsiveness, and are more environmentally sustainable.
▻http://news.microsoft.com/natick
▻http://www.projectnatick.com
▻https://www.youtube.com/watch?v=L2oJw1a_qEM
http://news.microsoft.com/natick/assets/photos/natick_2_web.jpg 
http://news.microsoft.com/natick/assets/photos/natick_7_web.jpg Article in New York Times:
►http://www.nytimes.com/2016/02/01/technology/microsoft-plumbs-oceans-depths-to-test-underwater-data-center.html
Even if putting a big computing tube underwater seems far-fetched, the project could lead to other innovations, he said. For example, the new undersea capsules are designed to be left in place without maintenance for as long as five years. That means the servers inside it have to be hardy enough to last that long without needing repairs.
Note: in 2013 Google already came in the news with its plans to build a datacenter on a ship
▻https://www.youtube.com/watch?v=ZYNwIfCb440
▻http://www.cnet.com/news/is-google-building-a-hulking-floating-data-center-in-sf-bay
So far, the only official link between Google and the sea, it the 2011 seawater-cooled datacentre of Hamina in Finland.
▻http://www.datacenterknowledge.com/archives/2010/09/15/google-using-sea-water-to-cool-finland-project
▻https://www.google.com/about/datacenters/inside/locations/hamina