(b) Construction in the basin, of bottom slabs and caisson 

 walls high enough to permit flotation. 



(c) Establishment of an outfitting site for completing 

 units before tow to final breakwater site. 



(d) Flooding of basin and towing of units to outfitting 

 site. 



(e) Completion of upper parts of units, ballasting, and 

 outfitting with handling gear. 



(f) Necessary bottom preparation at breakwater site. 



(g) Towing, locating, and sinking units at breakwater 

 site. 



(h) Completion of ballasting, interlocking keys, and 

 other onsite construction. 



Individual operations making up the program are discussed in the 

 following paragraphs. The complete operation is described in Section 

 111, 3; further description is included under Section IV which forms 

 the basis for the cost estimate. A general pictorial view of the onshore 

 construction areas is shown in Figure 5. 



3. Detailed Operations . 



a. Fabrication of Concrete Breakwater Units . The most economical 

 way to fabricate the precast concrete breakwater units is to first cast 

 a lower section with sufficient height to provide flotation, then tow 

 this section to a protected outfitting site in deeper water and construct 

 the remainder of the unit while floating. Casting the lower section can 

 be done in one of two ways. One way is to cast the lower section in a 

 drydock; however, few drydocks are capable of accommodating more than 

 two units at one time and the cost of a drydock specifically built for 

 this operation would be prohibitive. Another way is to excavate a large 

 basin in a protected cove along the shore to the required depth (as deep 

 as possible as governed by existing access channels). On the seaward 

 side, the basin would be enclosed by a dike as shown in Figure 16, Such 

 a basin would provide an area in which six units could be cast at one 

 time to a height of 50 feet. The minimum draft of each partially com- 

 pleted unit would be about 25 feet. After the six units are built to 

 this level, the basin would be flooded to float the units, and an opening 

 cut through the enclosing dike. At high tide the units would be towed 

 out, one at a time, and brought to an outfitting site where the units 

 can be completed. The dike opening is again closed, the water within 

 the basin pumped out, and construction started on six more units. 



Careful monitoring of adjacent shores during casting operations 

 must be maintained to determine the effect of such construction on the 



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