Analytical Approach to Cable Dynamics: Theory and User Manual

摘要

In order to transport a huge amount of liquid cargo, some 2,500 large tankers areused. One third of these tankers are foreign flagged. Because of the limiting water depth of California ports, tankers are often too large to enter the ports, which results in using a large number of smaller tankers to unload the oil from the large tankers and then bring the oil into the ports. This operation is called lightering. By 1990, the volume of oil handled by lightering was 1.75 million barrels per day, which was more than twice the volume four years ago. The use of a number of smaller tankers increases the possibility of collisions, grounding, operational casualties, fire/explosion, and overflows in the relatively shallow, narrow, congested and environmentally sensitive waterways. Oil spills are the direct result of these accidents. A report from the US Coast Guard Deepwater Ports Study (1993) indicates that lightering at sea and discharging in port. This is because lightering possesses all the possible conditions to generate the above mentioned accidents. A Single Point Mooring System (SPMS) is an alternative way to lighter. A SPMS generally consists of a buoy, a mooring system, and a riser. It is usually located in water deep enough for Very Large Crude Carriers (VLCC) and Ultra Large Crude Carriers (ULCC). Lightering is no longer necessary with using the SPMS. Thus, SPMS reduces the number of smaller tankers used. Also, the location of the SPMS is some distance from the coast, which provides some degrees of environmental protection through the space between coast and the SPMS.