385 



3. 500 Scries. — Two ships form this series. With the exception of depth, both 

 ships possess identical dimensions, displacement, liull form, accommodations and 

 machinery but differing tank configurations and deadweights. The base ship 

 (a), is similar to a design presently under construction. 



(a) 500-A: This design represents a nominal 500,000 DWT tanker. A 477,000 

 DWT ship was selected as a basis and modified to meet IMCO oil outflow require- 

 ments by increasing the subdivision and including a double bottom in the num- 

 ber 2 centerline tank. 



(b) 500-El : This design is similar to 500-A with the exception of a segregated 

 ballast capacity sufiicient to provide a ballasted displacement of 45% of full 

 load. The ballast is located in wing tanks placed intermittently along the ship 

 side. 



Stronger legislation could also incorporate more stringent constraints on 

 tank size and tank arrangement. As shown in table 4, a decrease in the value of 

 the hypothetical oil outflow from the values assigned in the bill cause a sub- 

 stantial increase in RFR. Decreasing the values of Oc and Os beyond the 20,000 

 cubic meter value causes RFR to increase at a rate greater than it does going 

 from 30,000 to 20,000 cubic meters. This is shown in figure 3. 



Stronger legislation could include a re-definition of oil as it is defined in the 

 Federal Water Pollution Control Act (FWPCA). as amended. Under the Oil Pollu- 

 tion Act of 1961, oil is defined to mean crude oil. fuel oil, heavy diesel oil and 

 lubricating oil. Under the FWPCA, oil is defined to mean oil of any kind or in any 

 form, including, but not limited to, petroleum, fuel oil, sludge, oil refuse, 

 and oil mixed with wastes other than dredged spoil. This broader definition 

 would make the Section of this bill implementing the Amendment to the Con- 

 vention dealing with tank size and arrangement applicable to vessels that carry 

 all petroleum based products and all animal and vegetable oils, not only to those 

 vessels carrying oil. as defined presently under the 1961 Act. 



Though keeping the definition of oil under the 1961 Act consistent with the def- 

 inition under the FWPCA, the U.S. would be taking action that no other nation 

 .signatory to the Convention is taking at this time. This unilateral action on the 

 part of the U.S. would impo.se requirements upon U.S. vesi^els which would place 

 them in a less favorable po.sition, vis-a-vis internati(mal trade. Furthermore, as 

 the bill is written in its present form, unless foreign flag vessels were constructed 

 to meet our requirements under the expanded definition of oil, they would be 

 prohibited from entering U.S. ports. Without a sufiicient number of U.S. vessels 

 available to carry the cargo no longer being carried by foreign flag vessels, the 

 U.S. would find itself in a position of having to back down on this definition of oil 

 under this Act. 



By implementing the 1969 and 1971 amendments to the Convention, this bill 

 provides the most effective means of working toward the goal of no harmful dis- 

 cbarges of oil into the oceans by 1980, while keeping the U.S. in step with the 

 muHilatcral action that IMCO proposes to meet the 1980 goal. 



