Panamax

Overall (including protrusions): 950 ft (289.56 m). Exceptions:

• Container ship and passenger ship: 965 ft (294.13 m)
• Tug-barge combination, rigidly connected: 900 ft (274.32 m) overall
• Other non-self-propelled vessels-tug combination: 850 ft (259.08 m) overall;

New Panamax increases allowable length to 366 m (1,201 ft).[2]

Width over outer surface of the shell plating: 106 ft (32.31 m). General exception: 107 ft (32.61 m), when draft is less than 37 ft (11.3 m) in tropical fresh water.

New Panamax increases allowable width to 49 m (161 ft).[2] Recently expanded to 51.25 m (168.14 ft)

The maximum allowable draft is 39.5 ft (12.04 m) in Tropical Fresh Water (TFW). The name and definition of TFW is created by ACP using the freshwater Lake Gatún as a reference, since this is the determination of the maximum draft. The salinity and temperature of water affect its density, and hence how deep a ship will float in the water. Tropical Fresh Water (TFW) is fresh water of Lake Gatún, with density 0.9954 g/cm³, at 29.1 °C (84 °F).[3] The physical limit is set by the lower (seaside) entrance of the Pedro Miguel locks. When the water level in Lake Gatún is low during an exceptionally dry season the maximum permitted draft may be reduced. Such a restriction is published three weeks in advance, so ship loading plans can take appropriate measures.

New Panamax increases allowable draft to 15.2 m (49.9 ft),[2] however due to low rainfall, the canal authority limited draft to 43 feet when the new locks opened in June 2016, increasing it to 44 feet (13.41 meters), in August "based on the current level of Gatun Lake and the weather forecast for the following weeks."[4]

Vessel height is limited to 190 ft (57.91 m) measured from the waterline to the vessel's highest point; the limit also pertains to New Panamax in order to pass under the Bridge of the Americas at Balboa harbor.[5] Exception: 205 ft (62.5 m) when passage at low water (MLWS) at Balboa is possible.

A Panamax cargo ship would typically have a DWT of 65,000–80,000 tonnes, but its maximum cargo would be about 52,500 tonnes during a transit due to draft limitations in the canal.[6] New Panamax ships can carry 120,000 DWT.[7] Panamax container ships can carry 5,000 twenty-foot equivalent units (TEU); with 13,000 TEU for New Panamax vessels.

The longest ship ever to transit the original locks was San Juan Prospector, now Marcona Prospector, an ore-bulk-oil carrier that is 973 ft (296.57 m) long, with a beam of 106 ft (32.31 m).[8] The widest ships to transit are the four battleships of both the South Dakota class and Iowa class battleships, which have a maximum beam of 108' 2" (32.96 m), leaving less than 6 in (15 cm) margin of error between the ships and the walls of the locks.[9]

The plans to build another set of larger locks led to the creation of the Neopanamax or New Panamax ship classification, based on the new locks' dimensions of 427 m (1,401 ft) in length, 55 m (180 ft) in beam, and 18.3 m (60.0 ft) in depth.[2] Naval architects and civil engineers began taking into account these dimensions for container ships.[11] With the new locks, the Panama Canal is able to handle vessels with overall length of 366 m (1201 feet), 49 meters beam (increased by the Canal Authority effective 1 June 2018 to 51.25 meters, to accommodate ships with 20 rows of containers) and 15.2 meters draft,[2] and cargo capacity up to 14,000 twenty-foot equivalent units (TEU);[12] previously, it could only handle vessels up to about 5,000 TEU.[13] The Neopanamax standard accommodates ships up to 120,000 DWT.[7]

Navigational clearance under the Bayonne Bridge in New York harbor was increased to accommodate New Panamax ships by building a new, higher roadway inside the arch and then removing the lower roadway.

Bayonne Bridge with old roadway removed over the water.

Several ports, including the ports of New York and New Jersey, Norfolk, and Baltimore, all on the East Coast of the United States, have already increased their depth to at least 50 feet (15 m) to accommodate New Panamax ships; in 2015 the Port of Miami achieved the same in a project known as the "Deep Dredge"[14] and is the closest deep-water port to the Panama Canal in the US. Liverpool built a new container terminal, Liverpool2, where ships berth in the tidal river rather than in the enclosed docks, coinciding with the opening of the widened Panama Canal locks. In Halifax a major expansion of the South End Container Terminal was completed in 2012, extending the pier and increasing the berth depth from 14.5 to 16 metres (48 to 52 ft).[15] In 2017, the Port Authority of New York and New Jersey raised the clearance of the Bayonne Bridge to 215 feet (66 m), at a cost of $1.7 billion, to allow New Panamax ships to reach container port facilities at Port Newark–Elizabeth Marine Terminal.[16] Previously, only GCT Bayonne, Global Container, could handle the New Panamax ships.

As of April 2012, a controversy between Savannah, Georgia, and Charleston, South Carolina, over limited federal funding for dredging/deepening projects—including both state and federal lawsuits filed by environmental groups in both states opposing the techniques planned to be used in dredging the Savannah River—also revolves around attracting the business of carriers whose fleets include New Panamax vessels. Jacksonville, Florida, is pursuing its "Mile Point" project with the prospect of deepening the St. John's River in anticipation of Post-Panamax traffic; Mobile, Alabama, has completed the deepening of its harbor to 45 feet (14 m) for the same reason; and other ports seem likely to follow suit.

A New-Panamax ship, the CMA CGM Theodore Roosevelt, about to transit New York Harbor via the heightened Bayonne Bridge

Due to the expansion, demand for 'Old Panamax' ships has plummeted, resulting in ships being traded at scrap value. Some ships only seven years old have been sold for scrap.[17][18]