As early as the 1930s, new locks were proposed for the Panama Canal to ease congestion and to allow larger ships to pass. The project was abandoned in 1942.
On October 22, 2006, the Panama Canal Authority (with the support of the Electoral Tribunal) held a referendum for Panamanian citizens to vote on the Panama Canal expansion project. The expansion was approved by a wide margin, with support from about 78% of the electorate. It is estimated that the project will be completed by 2014 and will cost $5.3 billion; this sum is expected to be recovered within 11 years.
The plans to build bigger locks have led to the creation of "New Panamax", based on new lock dimensions of 1,400 ft (427 m), beam 180 ft (55 m) and depth 60 ft (18.3 m). Naval architects and civil engineers are already taking into account these dimensions for container ships. The world's largest cruise ship, the Oasis of the Seas, has almost New Panamax dimensions but her height may prevent her passing under the Bridge of the Americas even at low tide.
After this expansion, the Panama Canal will be able to handle vessels of cargo capacity up to 13,000 twenty-foot equivalent units (TEU); currently, it can only handle vessels up to about 5,000 TEU. A third set of locks—1,400 ft (426.72 m) long, 180 ft (54.86 m) wide, with a draft of 60 ft (18.29 m)—will supplement the two existing sets.
However, even before the revised dimensions were announced, the Maersk E-class—like the Emma Maersk, the future Maersk Triple E Class, as well as many large tankers (ULCCs) and some bulk carriers (VLOCs)—will not be able to pass through even the new, much larger locks. The Maersk E and Triple E Class are too wide for even the new locks.
Several ports, including the ports of New York, Norfolk, and Baltimore, all in the northeastern US, have already increased their depth to at least 50 feet (15 m) to accommodate these changes, and the Port of Miami has recently approved doing the same in a project known as the "Deep Dredge" and will be the closest deep water port to the Panama Canal in the US. The Port Authority of New York and New Jersey is planning to raise the clearance of the Bayonne Bridge to 215 feet (66 m), at a cost of $1 billion, to allow New Panamax ships to reach container port facilities in New Jersey.