According to a report in the Times, the "water-based data centres" would use wave energy to power and cool their computers, reducing Google's costs.
Their offshore status would also mean the company would no longer have to pay property taxes on its data centres, which are sited across the world, including in Britain.
In the patent application observed by The Times, Google writes, "Computing centres are located on a ship or ships, anchored in a water body from which energy from natural motion of the water may be captured, and turned into electricity and/or pumping power for cooling pumps to carry heat away."
The increasing number of data centres necessary to cope with the massive information flows generated on popular websites has prompted companies to look at radical ideas to reduce their running costs.
The supercomputers housed in the data centres, which can be the size of football pitches, use massive amounts of electricity to ensure they do not overheat.
As a result, the internet is not very green.
Data centres consumed 1 per cent of the world's electricity in 2005. By 2020, the carbon footprint of the computers that run the internet will be larger than that of air travel, a recent study by McKinsey, a consultancy firm, and the Uptime Institute, a think tank, predicted.
In an attempt to address the problem, Microsoft has investigated building a data centre in the cold climes of Siberia, while in Japan the technology firm Sun Microsystems plans to send its computers down an abandoned coal mine, using water from the ground as a coolant.
Sun said it could save 9 million dollars of electricity costs a year and use half the power the data centre would have required if it was at ground level.
According to technology experts, Google's "computer navy" was an unexpected but clever solution.
"It's really innovative, outside-the-box thinking," said Rich Miller, the author of the datacentreknowledge.com blog.