approximately 0.4 percent of the cargo deadweight. In addition, consider- 

 able amounts of oil may remain in cargo tanks after cargo pumping 

 operations as a result of plugged limber holes and the resulting poor 

 drainage past structural members [31]. 



The recent "load on top" technique reduces the amount of oil 

 discharge to within the permissible limits of the present law. This 

 technique consists of pumping the oil residue from the tank cleaning 

 operation into an empty cargo tank. This mixture is then allowed to 

 separate by gravity (the oil normally is on top since its density is 

 usually less). Water is pumped overboard until the interface approaches 

 the suction line. The remaining fluid is a mixture of about 75 percent 

 oil, 25 percent water. This is transferred to a cargo tank in which new 

 oil is loaded on top. In the event that the new oil is of a different 

 type, then additional measures must be taken such as pumping the fluid 

 ashore or using it as fuel in the vessel's propulsion system after 

 further separation. 



The problems associated with this system relate more to practical 

 application than to theory. Analysis of this technique indicated that 

 effective oil/water separation may be adversely influenced by the follow- 

 ing [31]: (1) severe sea state conditions; (2) insufficient separation 

 periods due to short voyage (one tanker operator recommends 10 to 12 

 hours); (3) agitation due to the pumping operation itself; (4) cargo oil 

 having a specific gravity close to sea water; (5) inaccurate overboard 

 discharge measuring devices; and (6) human error. 



Community 



Moorings are located offshore and require limited onshore coastal, 

 facilities, making small increases in demand on public facilities. In" 

 the United States, SPM's are anticipated in locations where onshore 

 facilities, including tank farms, pipelines, and refineries are already 

 in place. SPM's merely offer a less expensive way to transfer crude. 



Employment : During construction, an average total work force of 

 less than 1,000 will be employed at each of the two proposed offshore 

 terminals (LOOP and Seadock), peaking at approximately 1,500. A majority 

 of the labor force will be employed in fabricating and installing offshore 

 facilities, and will not affect local communities. A smaller work 

 force, up to 380 workers, will construct the onshore facilities, including 

 docks, warehouse and terminal facilities. Established contractors and a 

 local labor force should conduct a majority of this onshore work. 



Employment upon completion is estimated at 300 workers to maintain, 

 operate and monitor the facilities [29, 30]. 



Induced Effects : Demand for services at the facility and by new 

 residents will strain a local economy in a rural region. In addition, 



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