rock properties are not nearly as significant in comparing anchor types 

 as are the mechanims for engaging the rock surface and the techniques 

 for installing the anchor system. Seafloor rock, category E of Table 1, 

 will be filled in as the data need develops. 



For each of the site categories, the performance of the various 

 anchor types was determined. Thereby, those anchor types best suited 

 for a given environment (and loading situation) were identified. 



Loading 



Horizontal . Given input information from some of the OTEC power 

 plant proponents/concepts, CEL established upper limits to the range of 

 horizontal load magnitudes to be considered in its anchor study. Because 

 the present designs are all preliminary and because this study is to 

 encompass all possible candidate power plant systems, the upper bouna to 

 required horizontal holding capacity was set at about twice the capacities 

 required for present plant concepts. For the deep ocean site, static 

 drag forces of 6 MN (1.27 x 10 lbs)and 9 MN (2 x lt}6 lbs) were estimated for 

 two concepts: for such a site, tne upper bound of the horizontal load 

 capacity range for this study was set at 18 MN frxlO lbsl For the Gulf 

 Stream environment, the^horizontal loading at the anchor was estimated 

 at 67 MN to 71 MN (15xl(T) and (1 5.9x10 lbs) for two concepts:' for the Gulf 

 Stream site, the upper bound of the horizontal load capacity range has 

 been set at 180 MN (40x10 lbs). Note that these load magnitudes are steady 

 state due to wind and current drag forces. The load component at the 

 anchor due to wave action on the floating structure is assumed to be 

 completely damped out by the mooring line system. 



Vertical . At the beginning of the CEL OTEC anchor effort a wide 

 spectrum of mooring line angles and vertical mooring line force compo- 

 nents was considered (Figure 2). Two loading envelopes were assumed. 

 The first, representing the deep ocean, "benign" environment, assumed a 

 maximum mooring line angle with the horizontal, 3, of 1.40 rad (80 degL 

 with a corresponding maximum vertical load component of 100 MN (22.7x10 lbs). 

 The high line angle of 1.40 rad was selected to include a proposed buoyant 

 line design in which the deep section of the mooring line was to be highly 

 positively buoyant rising at a steep angle from the anchor. The second 

 loading envelope, representing the Gulf Stream environment assumed a maxi- 

 mum mooring line angle of 0.79 rad (45 deg) with a corresponding maximum 

 vertical load component of 180 MN (40x10^ lbs). Reference to these 

 loading envelopes will be made throughout this report. 



The authors do make note here that, at the time of writing, the high 

 mooring line angles and the corresponding high vertical mooring line force 

 components at the anchor do not appear practical. Perhaps the most signif- 

 icant drawback to the high line angles in a conventional mooring would be 

 the increased stiffness of the moor and the resulting high dynamic load 

 carried in the mooring line and transmitted to the anchor and supporting 

 soil. Such high dynamic load acting on the predominantly calcareous oozes 



