Panamax
From Freepedia
Ships classified as Panamax are of the maximum dimensions that will fit through the locks of the Panama Canal. This size is determined by the dimensions of the lock chambers, and the depth of the water in the canal. Panamax is a significant factor in the design of cargo ships, with many ships being built to exactly the maximum allowable size.
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Dimensions
Panamax is determined principally by the dimensions of the canal's lock chambers, each of which is 33.53 meters (110 ft) wide by 320.0 meters (1050 ft) long, and 25.9 metres (85 ft) deep. The usable length of each lock chamber is 304.8 metres (1000 ft). The height of the Bridge of the Americas at Balboa is the limiting factor on a vessel's overall height.
The maximum dimensions allowed for a ship transiting the canal are [1]:
- Length: 294.1 meters (965 ft)
- Beam (width): 32.3 meters (106 ft)
- Draft: 12.0 meters (39.5 ft) in tropical fresh water (the salinity and temperature of water affect its density, and hence how deeply a ship will sit in the water)
- Height: 57.91 metres (190 feet) measured from the waterline to the vessel's highest point
Exceptions
Vessels up to 62.5 metres (205 feet) in height may pass by prior approval, co-ordinated with low tide at the Bridge of the Americas.
On an exceptional basis, vessels up to 32.61 metres (107 feet) in beam may be permitted to transit, subject to additional draft constraints.
Vessels with structures extending beyond the maximum length and/or beam above the level of the lock walls may be permitted transit subject to inspection and approval.
During an exceptionally dry season, when the water level in Lake Gatún is low, the maximum permitted draft may be reduced.
The longest ship ever to transit was the San Juan Prospector, now Marcona Prospector, an ore-bulk-oil carrier that is 296.57 metres (973 ft) long, with a beam of 32.3 meters (106 ft). The widest ships to transit are the U.S.S. New Jersey and her sister ships, which have beams of 32.92 metres (108 ft).
Impact on Shipping
Panamax continues to be a noteworthy factor in ship design, with an increasing number of ships being built precisely to the Panamax limit, in order to transport the maximum amount of cargo in a single vessel.
The increasing prevalence of vessels of the maximum size is a problem for the canal. A Panamax ship is a tight fit that requires precise control of the vessel in the locks, possibly resulting in longer lock time, and requiring that these ships be transited in daylight. Since the largest ships cannot pass safely within the Culebra Cut, the canal effectively operates an alternating one-way system for these ships.
Many modern ships, known as post-Panamax ships, are far larger than this (and hence cannot use the canal). This is the case for many modern container ships, although bulk merchandise such as grain products is moved primarily on Panamax (or sub-Panamax) ships.
U.S. Navy supercarriers are one type of vessel which are unable to fit through the canal locks.
Expansion
As early as the 1940's, new locks were proposed for the Panama Canal to ease congestion and to allow larger ships to pass. These plans remain speculative, hampered by considerations of cost and water supply (see Panama Canal).
