The 250 ^oot, high-strength alloy Chain Leader resists abrasion 

 by topographic features such as coral heads, boulders, cliffs, 

 etc. , while transmitting the tension in the array to the anchor. 

 Its length in conjunction with the lift from the 4 foot diameter buoy 

 (O. R. E. SS-48) above Station 1 provides clearance for the taut array 

 cable. The 1804 feet of wire rope between the buoy and Station 1 

 also serves to support the anchor during deployment and retrieval. 

 The Bridle straps are one foot long and the tension in the wire rope 

 at the attachment to the Bridle is 1050 lbs. Thus the upper straps 

 of the Bridle provide 18 foot-pounds of restraining torque per de- 

 gree of cable rotation. The lower straps provide additional restraint 

 of nearly the same stiffness. Knowledge of cable torque indicates that 

 no more than 10 degrees of cable rotation will occur. 



3.1.3 Outei- Mooring Assemblies 



The Outer Mooring Assemblies are designed to anchor the seaward 

 end of the taut array and, in conjunction with the Head Frame, to 

 prevent rotation at the seaward end. Figure 1-1 and the schematic 

 drawing given in Figure 3-3 illustrate the layout and function of these 

 moorings. Tables 3-4 and 3-5 provide summaries of the calculated 

 loads on the outer moorings and the clearances provided to the wire 

 rope by the Chain Leaders at critical currents. We see that the outer 

 moorings must resist dragging loads up to 7300 lbs. and lifting loads 

 of nearly 1800 lbs. The same factors mentioned above with respect 

 to the inner mooring apply here. We have selected 1900 lbs. (wet) 

 of heavy chain to isolate the Coral Hook from lifting loads. In order 

 to remain within safe cable loads during deployment the Coral Hook 

 is limited to 700 lbs. (wet). Clearly, we are depending upon an effec- 

 tive friction coefficient of 10 if the Coral Hooks are not to drag in 

 the 1.5 knot current. This does not seem unreasonable, especially 

 since some dragging of the outer anchors would bb tolerable. The 

 inner mooring coral hook must not drag, however, or tensioning of 

 the bottom cable would result. Note that the inner mooring coral 

 hook requires only an effective friction coefficient of 2. Each outer 

 mooring also has a 60H Hi-Strength Danforth anchor. The Coral 

 Hooks are fabricated of scrap I-beams. One is shown in Figure 3-9. 

 The roll bar prevents the structure from laying on its side. Again, 

 as in the case of the inner mooring coral hook, the width and height 

 of the structure is minimized to lessen drag and virtual mass forces 

 during lowering. Since the static load during lowering is about one 

 third of the cable's breaking strength, we were more concerned that 



204 



