According to this article, the US Navy is going to focus on using Open Source software for several reasons; mainly cost and control of software.
Probably the best quote from the article comes from Vice Adm. Mark Edwards himself, “The days of proprietary technology must come to an end,” he said. “We will no longer accept systems that couple hardware, software and data.”
No one should have to be tied so close to their systems that they have to pay large amounts of money just to get the software they need. It looks like the Navy took this idea to heart!