The U.S. Navy has long been willing to donate old ships to groups that were willing to maintain the retired vessels as museum ships. But the navy attaches some very expensive strings. That is, the navy expects the ship to be kept in decent shape. This is a problem with many old metal ships, as they rust. And eventually they rust so much that the hull is breached, and ultimately will collapse. For example, one museum ship, the World War II era, Essex class carrier USS Intrepid, in New York City, recently returned to its display berth after a two year refurbishment, costing $120 million. The entire hull was examined, in dry dock, for decay, and over a hundred square meters of hull had to be replaced. A sister ship of the Intrepid, the Yorktown, requires a similar refurbishment. Since 1975, the Yorktown has been on display in Charleston, South Carolina, with several other museum ships. The Yorktown, which entered service four months before the Intrepid, needs the same kind of work. The navy is insisting on it, with the alternatives being sending the ship to the breakers (to be broken up for scrap) or a lawsuit. The naval museum in South Carolina is in a bad situation, as $120 million is hard to find, even when the economy (and wealthy donors) are doing well. The big donors are much harder to find these days.
But even sending the ship to the scrap yard is not a viable alternative. For a long time, unneeded ships were "sent to the breakers" (a shipyard that broke the ship up for scrap and reusable parts). However, this is now considered environmentally harmful if done the old fashioned way (as it is still done in countries like India), and too expensive if it is done in an environmentally (and politically) acceptable way. In other words, it could cost more scrap the Yorktown than to repair her.
So what's to be done? A popular option these days is to use old ships for target practice. For example, of 31 recently decommissioned Spruance class destroyers, 22 were used for target practice. Some old warships are sunk closer to the shore, to provide reefs for fish and scuba divers.
But the museum would rather not lose the Yorktown, to the breakers, scuba divers or friendly fire. But unless the money can be found, the Yorktown will go down.