Merchant Marine Vessel Capacity

Merchant Marine Vessel Capacity

The average capacity of all vessels calling at U.S. ports grew 9 percent between 1998 and 2003 to 49,557 deadweight tons (dwt)1 per call, while the number of all vessel calls increased by only 1 percent [3]. The value of U.S. merchandise trade by maritime vessels grew from $614 billion to $811 billion during the same period [2].

The average capacity of containerships calling at U.S. ports increased 19 percent to 43,168 dwt per call between 19982 and 2003 (figure 13-5). Some of the largest containerships in the world are capable of carrying over 6,600 containers and have overall lengths of 1,138 feet [1].

The average capacity of gas carriers, such as liquid natural gas and liquid petroleum gas vessels, increased faster (by 26 percent from 30,000 to 38,000 dwts per call) between 1998 and 2003 than any other type of vessel calling at U.S. ports. The average capacity of combination vessels grew the least (1.4 percent) during this period. Tankers, which represent the largest average capacity vessel (72,387 dwt per call), grew 5.4 percent between 1998 and 2003.


1. Maersk-Sealand, Vessels web page, available at, as of June 2005.

2. U.S. Department of Commerce, U.S. Census Bureau, Foreign Trade Division, U.S. Exports of Merchandise and U.S. Imports of Merchandise, December (annual CDs).

3. U.S. Department of Transportation, Maritime Administration, Office of Statistical and Economic Analysis, Vessel Calls at U.S. Ports 2002-2003 (Washington, DC: 2004).

1 Deadweight tons refers to the lifting capacity of a vessel expressed in long tons (2,240 lbs), including cargo, commodities, and crew.

2 1998 is the first year for which data are available.