coastwise shipping

Technically, coastal shipping is conducted within 32 km (within 20 min) of the shoreline, but in practice ship lanes often extend beyond that distance, for reasons of economy and safety of operation. In the U.S., coastal shipping is conducted along the Pacific, Atlantic, and Gulf coasts. Under the restriction known as cabotage, the U.S. and many other nations permit only vessels registered under the national flag to engage in coastal trade. Among many small European countries cabotage does not apply, and short international voyages are common. A special feature of coastal shipping in the U.S. is the trade between the Pacific coast and the Atlantic and Gulf coasts. Vessels engaged in this trade traverse the open sea and utilize the Panama Canal; however, they are covered by cabotage laws. In coastal and short-distance shipping, special-purpose ships are often employed, such as car ferries and train ferries.