384 



Figure 2 shows plan views of the complete group of ships studied along with 

 principal dimensions, ballast location and quantity. It gives an indication of 

 the relative ship sizes and arrangements considered. 



A. Ships Configurations — 1. 250 Scries. — This series is comprised of a family of 

 eight ships develoi>ed in sufficient detail to establish construction cost. An addi- 

 tional version was developed only to the extent that its lack of feasibility could 

 be established. With the exception of depth all ships had identical dimensions, 

 displacement, hull form, accommodations and machinery but different tank con- 

 figurations and deadweights. In all design types the total segregated ballast 

 capacities include ballast carried in the forei>eak. the wing tanks, and other 

 miscellaneous tankage. The base ship, (a), is similar to an existing vessel. 



(a) 250-iA: This design is a single skin conventional ship of about 250.000 

 L.T. deadweight. It is tyi>ical of a large crude tanker now in operation. 



(b) 2r)0-A IMCO: This design represents one method of adjusting the de.sign 

 of 2riO-A to meet the IINICO oil outflow limitation of 30,000 cubic meters. This 

 design constitutes the correct base for comparison of the remaining variations 

 since all subsequent designs also meet the IMCO oil outflow limits. 



(c) 250-Bl : This design incorporates a B/15 double bottom depth with suflB- 

 cient depth increase to maintain required cubic. 



(d) 250-B2 : This design includes a double bottom of sufficient depth to provide 

 a total ship segregated ballast displacement of 45% of full load displacement. 



(e) 250^C : This design includes a double bottom wath a depth of B/15 plus 

 a double side skin of sufficient width to provied segregated ballast capacity 

 necessary for a segregated ballast displacement of 60% of full load di-splacement. 



(f) 250-D : This design includes double sides of sufficient width to yield a 

 segregated ballast displacement of 60% of full load displacement without a 

 double bottom. 



(g) 250-El : This de.sign represents a single .skin conventional tanker with 

 requisite depth increase needed to provide a segregated ballast displacement of 

 45% of full load displacement. The segregated ballast is carrietl in alternate 

 wing tanks. 



( h ) 250-E2 : This design has the same features as 250HE1, but provides sufficient 

 ballast to enable a segregated ballast displacement. 



(i) 250-F: An end point design not shown in Fig. 2 was considered wherein 

 both double bottoms and double skins were provided which met the IMCO dam- 

 age a.ssumptions, i.e. B/15 for bottom penetration and B/5 for side. 



2. 120 Series. — Two ships form this series. With the exception of depth, both 

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

 machinery but with different tank configurations and deadweights. The base 

 ship (a) is similar to an existing vessel now under construction. 



(a) 120-A : This design is a single .skin conventional tanker of about 120 000 

 L.T. deadweight. It provides a base price for evaluating the effect of changes. 



(b) 120-C : This design includes a double side and double bottom with a 

 depth of B/15. As on 250-C the segregated ballast displacement was maintained 

 at 60% of full load. 



