1950s S.S. United States

(12:45 p.m. EDT) -- S.S. United States' questionable future as a modern cruise ship no longer includes Crystal Cruises.

The line has axed plans to restore the historic liner, six months after signing a purchase option to turn it into an 800-passenger luxury liner with 400 suites. It has declined the purchase.

Following a technical feasibility study led by retired U.S. Coast Guard Rear Admiral Tim Sullivan and a team of experts, Crystal determined that although the ship was structurally sound, it presented technical and commercial challenges that posed a significant risk to the success of the project. To date, the project has cost Crystal more than $1 million.

In a statement, the line said "modifying the ship for today's standards for oceangoing service (SOLAS) would require significant changes to the hull that would pose stability challenges. Additionally, the installation of a modern, state-of-the-art diesel electric propulsion plant would have necessitated altering of the existing shaft lines and rebuilding about 25 percent of the hull to reconfigure the ship to a twin shaft-twin rudder arrangement."

The ship will remain docked on the Delaware River in Philadelphia, while the S.S. United States Conservancy continues its search for qualified developers and investors.

Crystal plans to donate $350,000 toward the Conservancy, whose mission is to preserve the vessel and educate the public on its history and legacy.

"We firmly believe the S.S. United States is an American treasure and deserves to be preserved and redeveloped as a stationary destination for future generations to experience and enjoy," said Crystal President and CEO Edie Rodriguez.

--By Gina Kramer, Associate Editor