Figure 1. Fabrication of spheres. 



of each hemisphere was epoxy-bonded into place. ■ Conventional 1/2-inch-diameter steel reinforcing 



The exterior surfaces of the hemispheres were lightly bars were embedded in the concrete of two spheres, 



sand blasted and a two-part phenolic compound Arrangement of the steel bars is shown in Figure 2. 



(Phenoline No. 300) was applied.'^ Finally, to fabri- Alternate longitudinal bars had a nominal concrete 



cate a sphere two hemispheres were bonded together, cover of 1 or 2.5 inches; however, in certain locations 



with an epoxy adhesive (Furane Epocast 8288). near the apex the minimum cover was as low as 0.5 



Figure 1 shows several of these operations. inch. 



All of the spheres had the same dimensions and Clocks were placed in Spheres 1 through 6 to 



variations in out-of-roundness. Extensive measure- record the day of implosion, if the sphere should fail, 



ments [8] were taken on one hemisphere, and Table The clock records days on a counter and has a 



2 summarizes the dimensions. In summary, the mean projected life of 3 years.^ Figure 3 shows the clock 



outside diameter was 65.886 inches and the mean and its pressure housing which was a 4-inch-OD pipe 



wall thickness was 4.124 inches. section. The pipe was attached to the top penetrator 



of the sphere 



Pinholes existed in the final waterproof coating at a rate of approximately 1 per 2 sq in. 

 For zero time in the ocean, the clocks read 41 days for Spheres 1-3, and 38 days for Spheres 4-6. 

 ■' Upon retrieval, safety precautions should be followed in handling the pressure housing because 

 water at high pressure could be inside. Prior to opening, drill a 1/8-inch-diameter hole through 

 the steel wall to relieve any internal pressure. 



