Britain's two new aircraft carriers, which were designed by a French firm, are accused of secretly having their design modified so the ships could move under the Forth Rail Bridge that crosses the Forth estuary in Scotland. The Rosyth shipyard, where the two carriers will be built, cannot build ships talker than 150 feet (from the waterline) as the only access to the sea is under the Forth bridge. At high tide, the bridge is 150 feet above the water. The two carriers, which will be called HMS Queen Elizabeth and HMS Prince Charles, will displace 60,000 tons and will be built in four "blocks" in other locations. The blocks will be floated to the Rosyth yards, assembled and the ships finished and ready for service (sometime in 2015). Over $160 million has already been spent on designing the ships. American Nimitz class carriers, which displace 90,000 tons, are about 206 feet tall, measured from the waterline to the topmost mast. There are even some sailing ships that have are taller than 150 feet. The carrier designers say the design of the ships took the bridge height limitations into account from the beginning, and the design did not have to be later modified for that. Such modifications are not unknown, as the Forth Rail Bridge situation is not unique. In such situations, the tallest masts are built so they can be lowered temporarily. Cynical pundits and reporters are not so sure the French ship designers were so well informed about the Forth Bridge.