power module, additional assumptions must be made. For the purposes of 

 this study, the load module is assumed to have the same volume as but less 

 weight than the power module. It was also assumed that the load module 

 was contained in a single cylindrical or spherical pressure hull. If the load 

 was inhabited, personnel shielding and personnel transfer chambers, which 

 add weight and volume to the load module, would have to be considered. 



Several arrangements were considered for the power and load module 

 configurations. The conceptual arrangements included power plant and load 

 modules side by side, load module mounted atop the power plant (piggy 

 back), load module remotely located from power module, and load module 

 and power module in a common pressure hull. Figure 4 illustrates some of 

 the conceptual arrangements considered in this study. 



The in-situ plant configuration would be selected on the basis of 

 power level, load module dimensions, load module weight, and load module 

 mission. The power level effect is determined by the requirement for vertical 

 cylinder or horizontal cylinder pressure hulls. A limitation on the selection 

 of a configuration can be made by considering the weight of the load module. 

 To avoid requirements for trimming, the load module could be situated side- 

 by-side with the power module if the weights are identical. If the weights 

 are not equal, then the load module (assumed the lightest) could be mounted 

 atop the power module. The arrangement selected must maintain the overall 

 center of gravity within limits governing hydrodynamic stability and must 

 resist overturning moments. The mission of the load module and the orienta- 

 tion of the load module relative to the ocean bottom have a definite effect 

 on the selection of the in-situ plant configuration. 



Buoyancy Variations. Variations of buoyancy with depth must be 

 evaluated before a final in-situ plant configuration is selected. These changes 

 in buoyancy are dependent on the physical environment in which the plant 

 operates and the characteristics of the pressure hull and its materials. Since 



it follows that 



B = dV 



AB = dAV + VAd + Ad AV 



where B = buoyancy 



d = density, Ib/ft^ 



V = volume, in.'^ 



A = a discrete change to the particular factor 



24 



