general rule-handymax ca 35000-50000 tons, Supramax 50-60k tons and Panamax 60-80 k tons but cant carry full load thru the canal due to 39.5 ft (12.04 m) in Tropical Fresh Water draft-but we dont have to worry about that
Panamax
Panamax and New Panamax are terms for the size limits for ships traveling through the Panama Canal . Formally, the limits and requirements are published by the Panama Canal Authority (ACP) titled "Vessel Requirements". [ 1 ] These requirements also describe topics like exceptional dry seasonal limits, propulsion, communications and detailed ships design.
The allowable size is limited by the width and length of the available lock chambers, by the depth of the water in the canal and by the height of the Bridge of the Americas since that bridge's construction. These dimensions give clear parameters for ships destined to traverse the Panama Canal, and have influenced the design of cargo ships, naval vessels, and passenger ships.
"Panamax" has been in effect since the opening of the canal in 1914. Ships that do not fall within the Panamax-sizes are called Post Panamax . In 2009 the Canal management published the "New Panamax", [ 2 ] that will be in effect when the third lane of locks , larger than the current two, becomes operational in 2015.
The increasing prevalence of vessels of the maximum size is a problem for the canal as 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 transit in daylight. Because the largest ships traveling in opposite directions cannot pass safely within the Culebra Cut , the canal effectively operates an alternating one-way system for these ships.
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Panamax dimensions
Panamax is determined principally by the dimensions of the canal's lock chambers , each of which is 110 ft (33.53 m) wide by 1,050 ft (320.04 m) long, and 41.2 ft (12.56 m) deep. The usable length of each lock chamber is 1,000 ft (304.8 m). The available water depth in the lock chambers varies, but the shallowest depth is at the south sill of the Pedro Miguel Locks and is 41.2 ft (12.56 m) at a Miraflores Lake level of 54 ft 6 in (16.61 m). The height of the Bridge of the Americas at Balboa is the limiting factor on a vessel's overall height; the exact figure depends on the water level.
The maximum dimensions allowed for a ship transiting the canal are: [ 1 ]
Length
Over all (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) over all
- Other non-self-propelled vessels-tug combination: 850 ft (259.08 m) over all
Width (beam)
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.
Draft
39.5 ft (12.04 m) in Tropical Fresh Water (TFW). The name and definition of TFW is created by ACP using the freshwater Gatun Lake 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 Gatun Lake, with density 0.9954 gms/cc [0.9954 g/cm 3 ], 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.
Air draft
190 ft (57.91 m) measured from the waterline to the vessel's highest point; limit also pertains to Balboa harbor. Exception: 205 ft (62.5 m) with passage at low water (MLWS) at Balboa is possible.
All exceptions are typically allowed only after specific request, an investigation and on a one- or two-time only basis.
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. [ 4 ]
